Challenges and Benefitsof Standardising Early WarningSystems: A Case Studyof New Zealand’s Volcanic AlertLevel System

Sally H. Potter, Bradley J. Scott, Carina J. Fearnley ,Graham S. Leonard and Christopher E. Gregg

AbstractVolcano early warning systems are used globally to communicatevolcano-related information to diverse stakeholders ranging from specificuser groups to the general public, or both. Within the framework of avolcano early warning system, Volcano Alert Level (VAL) systems arecommonly used as a simple communication tool to inform society aboutthe status of activity at a specific volcano. Establishing a VAL system thatis effective for multiple volcanoes can be challenging, given that eachvolcano has specific behavioural characteristics. New Zealand has a widerange of volcano types and geological settings, including rhyolitic calderascapable of very large eruptions (>500 km3) and frequent unrest episodes,explosive andesitic stratovolcanoes, and effusive basaltic eruptions at bothcaldera and volcanic field settings. There is also a range in eruptionfrequency, requiring the VAL system to be used for both frequently active‘open-vent’ volcanoes, and reawakening ‘closed-vent’ volcanoes. Fur-thermore, New Zealand’s volcanoes are situated in a variety of risksettings ranging from the Auckland Volcanic Field, which lies beneath acity of 1.4 million people; to Mt. Ruapehu, the location of popular skifields that are occasionally impacted by ballistics and lahars, and producestephra that falls in distant cities. These wide-ranging characteristics andtheir impact on society provide opportunities to learn from New Zealand’s

S.H. Potter (&) � B.J. Scott � C.J. Fearnley �G.S. Leonard � C.E. GreggDepartment of Science and Technology,University College London, Gower Street,London WC1E 6BT, UKe-mail: S.Potter@gns.cri.nz

C.J. Fearnleye-mail: c.fearnley@ucl.ac.uk

S.H. Potter � G.S. LeonardGNS Science, 1 Fairway Drive, Avalon,Lower Hutt 5010, New Zealande-mail: G.Leonard@gns.cri.nz

B.J. ScottGNS Science, 114 Karetoto Road, RD4,Taupo 3384, New Zealande-mail: B.Scott@gns.cri.nz

C.E. GreggDepartment of Geosciences, East TennesseeState University, Box 70357, Johnson,TN 37614, New Zealande-mail: GREGG@mail.etsu.edu

https://doi.org/10.1007/11157_2017_18© The Author(s) 2017Published Online: 30 August 2017

Advs in Volcanology (2018) 601–620

experience with VAL systems, and the adoption of a standardised singleVAL system for all of New Zealand’s volcanoes following a review in2014. This chapter outlines the results of qualitative research conducted in2010–2014 with key stakeholders and scientists, including from thevolcano observatory at GNS Science, to ensure that the resultingstandardised VAL system is an effective communication tool. A numberof difficulties were faced in revising the VAL system so that it remainseffective for all of the volcanic settings that exist in New Zealand. Ifwarning products are standardised too much, end-user decision makingand action can be limited when unusual situations occur, e.g., there maybe loss of specific relevance in the alert message. Specificdecision-making should be based on more specific parameters than theVAL alone, however wider VAL system standardisation can increasecredibility, a known requirement for effective warning, by ensuring thatwarning sources are clear, trusted and widely understood. With a crediblesource, user groups are less likely to look for alternatives or confirmation,leading to faster action. Here we consider volcanic warnings within thewider concept of end-to-end multi-hazard early warning systems includingdetection, evaluation, notification, decision-making and action elements(based on Carsell et al. 2004).

KeywordsVolcanic Alert Level � Early warning system � Standardisation �New Zealand

1 Early Warning Systemsand Standardisation

An Early Warning System (EWS) can be definedas a system designed to provide “hazard moni-toring, forecasting and prediction, disaster riskassessment, communication and preparednessactivities, systems and processes that enablesindividuals, communities, governments, busi-nesses and others to take timely action to reducedisaster risks in advance of hazardous events”(UN 2003). They are recognized as “a means ofgetting information about an impending emer-gency, communicating that information to thosethat need it, and facilitating good decisions andtimely response by people in danger” (Mileti andSorensen 1990, p. 2–1). Essentially EWSs facil-itate the provision of timely warnings to mini-mize loss of life and to reduce economic and

social impact on vulnerable populations (Garciaand Fearnley 2012).

The operation of an EWS presents numerouschallenges due to variations in: scale (global,national, regional, local); temporality (rapidonset, slow onset, frequent, infrequent); function(safety, property, environment); and hazard (e.g.,weather, climate, geohazards). A Volcano AlertLevel (VAL) system is a communication toolwithin a volcano EWS, which simplifies thecommunication of volcanologists’ interpretationof data (Newhall 2000). The VAL system isdisseminated with supporting information thatprovides more specific details and local contextto enable responding agencies, the public, andother stakeholders to make informed decisions(Fearnley 2011; Potter et al. 2014). The levelscan be labelled using words, numbers, colours,and/or symbols, and summarise information from

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‘background’ activity (no unrest), through to thehighest level of activity (usually a large eruption)(Newhall 2000; Fearnley 2011).

Volcano observatories play a key role in themanagement and assignment of alert levels forvolcanoes. However, with over 80 volcanoobservatories around the world, it is under-standable that VAL systems operate in very dif-ferent ways. Some provide only scientific adviceon what a volcano is doing, others forecastactivity, and others provide guidance on whatvulnerable populations should do. There is agrowing discussion globally around the role ofVAL systems and whether they should be stan-dardised, either nationally and/or internationally.

In 1989, the member states of the UnitedNations declared the period from 1990 to theyear 2000 to be the International Decade forNatural Disaster Reduction (IDNDR) to focusattention on reducing loss of life, and social andeconomic disruption caused by natural disasters.Of fundamental importance was the recognitionin 1991 of early warnings as a key objective ofdisaster reduction practices (Maskrey 1997). TheUnited Nations has called for more effectiveprocedures via standardisation and the applica-tion of new technologies and enhanced scientificunderstanding (United Nations 2006) but fewhazards have an EWS operating beyond anational or regional scale. The most successfulexample is the Pacific Tsunami Warning Centre(PTWC), established in Hawaii in 1949. Untilrecently, PTWC provided Warning and Watchalert level services for numerous Pacific nationsand beyond, but currently they provide nationswith threat level information (e.g., wave ampli-tude forecasts), which the countries then usein-house to develop and disseminate specifictsunami alert levels (i.e., Warning, Watch).

The growing pressure on volcano observato-ries to standardise warnings is felt especially inrelation to provision of advice and alert levels tothe aviation sector. In 2006, the InternationalCivil Aviation Organization (ICAO) globallystandardised a considerable portion of products,including the alert levels (via the Aviation Col-our Code (ACC); Table 1), messages to airlinesthat observatories are expected to provide (via

the Volcano Observatory Notice for Aviation;VONA), and the framework for monitoring andalerting related to ash clouds (via the VolcanicAsh Advisory Centres; VAACs). While VAACsprovide the aviation community with informationregarding where ash currently is in the air, therole of the ACC is more about warning (Gardnerand Guffanti 2006). The ACC allows a recogni-tion of the level of volcano activity for the pur-pose of attention by the aviation industry, and toinform their decisions, such as regardingre-routing or extra fuel (Gardner and Guffanti2006). VONAs are standardised plain-Englishmessages aimed at dispatchers, pilots, andair-traffic controllers ‘produced by VolcanoObservatory scientists and are based on analysisof data from monitoring networks, direct obser-vations, and satellite sensors’ (as described onthe USGS website1). The international nature ofthese aviation products reflects the need for avi-ation personnel to ascertain the status of volcanicactivity across a number of countries and VALsystems (e.g., Guffanti and Miller 2013), whichis why a standardised approach is used. Whileworking fine for international air traffic, problemshave been encountered for low-level domesticand private aviation with the ACC (Fearnley2011).

Numerous volcano observatories across theworld are now implementing the ACC, and manyof these are questioning the adoption of otherVAL systems for ground-based hazards andreviewing their volcano early warning systems.This includes reviewing the effectiveness of VALissuances, as Winson et al. (2014, p. 12) invite“countries to perform their own self-evaluationand weigh the cost of a higher number of alertsagainst the benefit of a higher accuracy in VALissuances and to decide how to proceed accord-ingly with their own local populations”.

The benefits of standardisation are principally:

• simplicity through application of commonlanguage, frameworks and understanding;

• clarity for emergency responders;

1https://volcanoes.usgs.gov/vhp/notifications.html accessed11 May 2017.

Challenges and Benefits of Standardising Early … 603

• reduced workload for monitoring and emer-gency management agencies, including edu-cation and outreach;

• interoperability of equipment and systemsacross hazards, and across agencies, countriesor internationally.

Warning messages with specific language andapproaches can benefit from standardisation. Indoing so, it is advisable to publish and makeaccessible the definitions of technical volcanicterms, and of the words ‘risk’ and ‘hazard’ asused by the scientists. This is to ensure localusers understand the intention behind the scien-tist’s use of the terms. For example, calculationof ‘hazard’ can be based on previous events,deterministic and/or probabilistic approaches,and should be described. In addition, the com-munication of likelihood/probability can also bea point of confusion; ideally numeric valuesshould be mapped against qualitative descrip-tions and both presented together (e.g., Doyleand Potter 2016). Standardisation can alsoincrease credibility, a known requirement foreffective warning, by producing warnings thatare clear, and from a trusted source. With acredible source user groups are less likely to lookfor alternatives or confirmation, leading to fasteraction. However, end-user decision making andaction can be limited in terms ofcontingent-specific-needs if warning products arestandardised too much (e.g., depending on auser’s ability to read different types of maps(Haynes et al. 2007); or loss of meaning or rel-evance in the warning within a local context).

There are various elements of end-to-endwarnings that lend themselves to standardisa-tion that can aid the effectiveness of the VALsystem:

• Technical: Equipment type, deployment(distribution/location/density), telemetry (ra-dio, wire, internet etc.), visualization (soft-ware packages) and analysis all receive somelevel of standardisation through manufactur-ing standards, detection limits, and interna-tional scientific best practice.

• Analytical tools: Analysis may be furtherstructured through statistical approaches suchas expert elicitation, Bayesian event trees orBayesian belief networks.

• Warning tools: Notification may be stan-dardised through message content (e.g.,standard messages, terminology, alert levelcriteria), packaging (e.g., bulletins, alertlevels, maps) and delivery channels (e.g.,phone, internet, siren). Some standards lendinteroperability, such as a Common AlertingProtocol.

• Response: Decision-making and action by theend-user can be standardised to some extentthrough communication and educationapproaches and message content.

Clearly there are cases where standardisationprovides many advantages, but the process ofstandardisation is predominantly triggered andshaped by social, political, and economic factors,rather than in response to scientific needs specificto a region. Standardisation, by definition, tendsto exclude the importance of incorporating localfactors into a global procedure. Hence, even ifstandardisation may yield improved strategies forgathering and interpreting warning signals, it willstill favour inflexible procedures not designed toaccommodate local social and cultural con-straints. Challenges are brought about by a rangeof issues (Fearnley 2011, 2013), especially:

• the realities of varied volcanic systems, eachbeing geophysically unique when examinedin detail. The diversity and uncertain natureof numerous hazards that can occur at dif-ferent temporal and spatial scales requirespecific EWSs to be developed.

• varied end-users with different needs andperspectives for their decision-making, interms of the level of volcanic activity, andtiming thresholds for response actions.

• multiple local social and cultural contexts andconstraints, which presents challenges inrelation to the applicability and responsive-ness of EWSs to local knowledge andcontext.

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In recent decades, standardisation within VALsystems at a national level has taken place,making provision for consistency of warningsenacted by civil authorities that are required totake action and facilitate national policies foremergency management. VAL systems in anumber of countries (including Japan via theJapan Meteorological Agency (JMA), Vanuatuvia GeoHazards, the USA via the USGS, andNew Zealand via GNS Science) have beenstandardised in each country for use by all vol-canic observatories. Yet, there are variances inthe way VAL systems are being standardised. Inthe USA, for example, two standardised VALsystems are now in place: a textually based ver-sion for ground hazards (e.g., watch, warning)and the aviation colour code that uses colours aslabels. In New Zealand, the VAL systemsadopted in 1994 and reviewed in 1995 also usedtwo standardised VAL systems: one designed forhazards expected at frequently active volcanoesand the other for restless and reawakening vol-canoes (see Table 2). Both of the NewZealand VAL systems were numerically basedusing six levels ranging from 0 to 5 (Scott andTravers 2009). Another review in 2014 resultedin these two systems being combined into one(Potter et al. 2014), whilst also adopting theinternational aviation colour code (ACC). Nota-bly, both the USA and New Zealand VAL sys-tems are based upon the current activity of avolcano, and neither advocate action nor provideadvice to users involved in crisis managementand mitigation—this information is provided inother products. In sharp contrast, theJapanese VAL system addresses the measures tobe taken for specific areas of danger, indicatingextent of evacuation, and outlining the expectedvolcanic activity.2

This chapter focuses on the standardisation ofVAL systems using the case study of NewZealand in the revision of the VAL system in2014, to explore the benefits and challenges inimplementing a nationally standardised VALsystem. Reflections upon its success will help

inform others as to why the devised national alertlevel in New Zealand is best placed for theirnation, and why perhaps an international level ofstandardisation for VAL systems is still some-thing that is unadvisable, and unfeasible.

1.1 Overview of New Zealand’sVolcanic Risk Setting

New Zealand straddles the boundary between thePacific Plate and the Australian Plate. Theresulting subduction zone lies beneath a riftingarea of thin crust with magmatic upwelling,called the Taupo Volcanic Zone (TVZ; Fig. 1).The TVZ contains most of New Zealand’s activevolcanoes, and includes stratovolcanoes andcalderas.

New Zealand has a range of volcanic risksettings that creates a challenge in effectivelycommunicating scientific information to stake-holders, including the public. In terms of hazard,the volcanoes have large differences in thepotential eruption styles and magnitudes oferuptions, reflected by variations in magmachemistry. The past frequency of eruptions andthe date of the most recent eruption also varyconsiderably between them, which contributestowards a range in the likelihood element of therisk equation. The exposure and vulnerability ofcommunities to unrest and eruptions also differs,with some volcanoes (such as Ruapehu, Ngau-ruhoe, and Tongariro) situated in a largelyunpopulated National Park; and others areislands in the Pacific Ocean with few permanentresidents (such as Raoul Island in the Ker-madecs). Other volcanoes, such as AucklandVolcanic Field, Taupo Volcanic Centre, OkatainaVolcanic Centre and Rotorua Caldera volcano,are in close proximity to cities. A few of thevolcanoes receive tens of thousands of visitorseach year, and are used commercially by touristoperators (including Whakaari/White Island).Others, such as Taranaki volcano, are surroundedby fertile agricultural land and are near importantnational infrastructure. Each of these elements ofrisk (hazard characteristics, likelihood, exposureand vulnerability) influence the type of

2www.data.jma.go.jp/svd/vois/data/tokyo/STOCK/kaisetsu/English/level.html accessed on 11 May 2017.

Challenges and Benefits of Standardising Early … 605

Fig. 1 Map of New Zealand’s volcanoes, from Potter(2014), and based on Smith et al. (1993), Nairn (2002),Wilson et al. (2009), and Lindsay et al. (2010). The TaupoVolcanic Zone (TVZ; depicted as a dashed line) envelopsthe majority of the volcanoes. The calderas (polygons) are

MI Mayor Island; Ro Rotorua; OVC Okataina VolcanicCentre; Kp Kapenga; Rp Reporoa; Oh Ohakuri; MgMangakino; Wh Whakamaru; and TVC Taupo VolcanicCentre. The volcanic fields are indicated by ovals withdiagonal lines

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communication and information required, as thelocal context needs to be considered.

The Tongariro Volcanic Centre is the south-ernmost volcanic complex of the TVZ, andincludes the frequently active andesitic Ruapehuand Ngauruhoe/Tongariro stratovolcanoes.Lahars have frequently occurred, causing a haz-ard in numerous valleys on the volcanoes (e.g.,Leonard et al. 2008). Ruapehu hosts popular skiareas, and last erupted with vigour in 1995–96(Hurst and McGinty 1999). Small eruptions withshort durations also occurred in October 2006and September 2007. Volcanic unrest ison-going. Ngauruhoe is the most frequentlyactive vent of the Tongariro massif, displayingregular eruptions until 1977 (Scott 1978), butnone since. Te Maari Crater and Red Crater onnorthern Tongariro were active in the late 19thCentury, with frequent eruptions in 1896–97(Scott and Potter 2014). After less than onemonth of minor unrest, Te Maari Crater was thesource of two small, short-lived phreatic erup-tions on 6 August and 21 November 2012(Fig. 2). There were no casualties, however thetourism industry was impacted due to the closureof a popular walking track (the Tongariro AlpineCrossing) by the Department of Conservation(DoC), which manages the National Park.

There are eight areas of known caldera col-lapse in the central TVZ (Fig. 1), which itself canbe considered to be a caldera system similar toYellowstone in the USA. Although calderas areusually formed in occasional very large erup-tions, their magma system can also be the sourceof many smaller eruptions. The calderas in theTVZ have erupted almost exclusively rhyoliticmaterial in at least 25 caldera-forming eruptionsin the last 1.6 million years (Wilson et al. 1984,2009). Only <0.1% of the volume of deposits inall of the TVZ are from basaltic eruptions(Wilson et al. 1995). The caldera volcanoes havea large range in past eruption magnitudes. Forexample, the TVZ’s most-recent caldera collapsetook place at Taupo Volcanic Centre (TVC) in232 ± 5 AD, erupting 35 km3 of magma(Wilson 1993; Davy and Caldwell 1998; Self2006; Hogg et al. 2012). This devastated a sig-nificant portion of the central North Island inwidespread pyroclastic density currents (Wilsonand Walker 1985). However, 26 of the 29 erup-tions at TVC in the past 26,000 years (since thelast supervolcano eruption) have been muchsmaller than the most recent eruption (Wilsonet al. 2009). Therefore, it is unknown whetherfuture eruptions at TVC will be relativelysmall, as has been the case most frequently, or

Fig. 2 Eruption at Te MaariCrater, Tongariro, on 21November 2012, captured bythe GeoNet Te Maari Craterweb camera (GNS Science)

Challenges and Benefits of Standardising Early … 607

devastatingly large, as was the case with the mostrecent eruption. An additional challenge ismanaging caldera unrest, which can cause socialand economic impacts, without a resultingeruption (Potter et al. 2012, 2015).

The north-eastern extremity of the TVZcontains White Island (Whakaari), a privatelyowned andesitic stratovolcano located 50 kmfrom the Bay of Plenty coastline. It is currentlyNew Zealand’s most frequently active volcano,and a popular tourist destination with approxi-mately 25,000 tourists and tourist operatorsvisiting the island per year. Frequent eruptivesequences have been documented since writtenrecords began in 1826 (Nairn et al. 1991), withthe most recent eruptions occurring in 2016.New Zealand is also responsible for a numberof other island volcanoes, including MayorIsland in the Bay of Plenty, and Raoul andMacauley Calderas in the Kermadec Islandchain, 750–1000 km northeast of New Zealand.These islands have very few visitors or resi-dents. About 30 submarine volcanoes are alsoknown in the Kermadec area and some exhibiteruptive activity. Due to the lack of monitoringdata, a VAL is not allocated to them.

Taranaki Volcano is a stratovolcano located inthe west of the North Island, outside of the TVZ.It is thought to have last erupted in 1755 AD(Druce 1966), but it may have subsequentlyextruded lava, forming a dome after this date(Platz 2007). It is capable of fairly large erup-tions, and has a history of sector collapse (e.g.,Neall 2003). Taranaki Volcano is surrounded byproductive agricultural land and is in a majorhydrocarbon (gas and oil) production region.There is a regional population of just over100,000 people, most of whom live in the city ofNew Plymouth.

The intraplate Puhipuhi-Whangarei VolcanicField (PWVF), the Kaikohe-Bay of IslandsVolcanic Field (KBOIVF) and Auckland Vol-canic Field (AVF) are in northern New Zealand(Fig. 1). PWVF is thought to have been active asrecently as 0.26 Ma, while dating of theKBOIVF indicates an eruption occurred at about0.05 Ma (Smith et al. 1993), or perhaps asrecently as in 200–500 AD (Kear and Thompson

1964). AVF has had many eruptions from at least53 basaltic vents, most recently about 600 yearsago (e.g., Needham et al. 2011). Auckland cityhosts a third of New Zealand’s population with1.4 million residents, and is sited directly on topof AVF.

Eruptions from most of New Zealand’s vol-canoes are likely to impact infrastructure ofnational importance, including many StateHighways and road networks, electricity linesand power stations, train lines, water supplies,and sewage facilities (Wilson et al. 2012).Additionally, industries important to the local,regional, and national economies may be threat-ened during future eruptions, including thetourism, agricultural, forestry, and hydrocarbonindustries.

1.2 Communication of Volcano-Related Informationin New Zealand

In New Zealand, GNS Science is the agencyappointed by the Government to provide scien-tific advice to local, regional, and central gov-ernment organisations for geological hazards,as stated in the Guide to the National CivilDefence Emergency Management (CDEM)Plan (MCDEM 2015a) and a Memorandumof Understanding with the Ministry of CivilDefence and Emergency Management(MCDEM)(GNS Science, The Ministry of CivilDefence and Emergency Management 2015).The MOU outlines the obligations of GNS Sci-ence for geohazard warnings, whereas the Guideto the CDEM Plan is to assist New Zealandagencies to achieve the objectives of theNational CDEM Plan (MCDEM 2015b). NewZealand’s volcanoes are today monitored byGNS Science through the GeoNet project (Scottand Travers 2009), funded primarily by the NewZealand Earthquake Commission (EQC).

Volcano-related information is communicatedto stakeholders, including the public, in a varietyof formats before, during, and after volcaniccrises. The primary tool used is the VolcanoAlert Bulletin (VAB), supported by web page

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information on GeoNet News,3 blogs, newsitems and social media tools (Facebook, twitter).Volcano hazard and status information is alsopresented by scientists during meetings, confer-ences, workshops, and public lectures; websites;in scientific and non-scientific publications; andvia the media. Smartphone app push alerts,emails, faxes, pager alerts, and text messagesprovide one-way information to registeredend-users during crises or changes in volcanicactivity. Volcanic ash impact posters (a productof the Volcanic Impact Study Group, commis-sioned by the Auckland Lifelines Group) provideaccessible information for critical infrastructurestakeholders (Wilson et al. 2014). Social mediaand ‘ask an expert’ interactive online sessionsallow questions to be asked by the public andanswered by scientists in real-time. Informalconversations during meetings, workshops, or bytelephone provide end-users with more specificinformation from volcanologists, with theopportunity for two-way communication. Anexample of this is during Volcanic AdvisoryGroup meetings, which are attended by keystakeholders and volcanologists to discuss vol-cano- and response-related information (Doyleet al. 2011). Long-term hazard maps have beencreated for some of the more active volcanoes,based on geological evidence of past eruptions(Neall and Alloway 1996; Scott and Nairn 1998).Event-specific hazard maps are created duringunrest depending on the situation, likely ventlocation, and the style and magnitude of thepotential eruption, etc. Event-specific hazardmaps were created prior to and after the Ton-gariro eruption in 2012 (Leonard et al. 2014).

New Zealand’s VAAC, based at the Meteo-rological Service of New Zealand Ltd. (MetSer-vice) office in Wellington, is designated by theInternational Airways Volcano Watch system tocommunicate ash information for a large sectionof the southwest Pacific, including New Zeal-and’s active volcanoes (Lechner 2012). MetSer-vice issues Volcanic Ash Advisories in a text andgraphic form, and disseminates a Significant

Meteorological Information (SIGMET) message,while Airways Corporation issue Notice to Air-men (NOTAM), which draws attention to vol-canic ash hazards within the NZ VAAC area.These globally standardised messages are alsoissued when New Zealand’s VAL changes,prompting restrictions to local air space. Afterconsultation with GNS Science for NZ volca-noes, Volcanic Ash Advisories are communi-cated by the VAAC to MCDEM, in addition tobeing provided to international aviation agenciesand meteorological communities (MCDEM2015a). Volcanic Ash Advisories from MetSer-vice forecast the distribution of volcanic ash inthe atmosphere for the purpose of aviation safety,whereas GNS Science issues ashfall predictionmaps as a VAB, relating to the distribution andthickness of tephra deposits at ground level. Inaddition to these systems, GNS Science issuesVolcano Observatory Notices for Aviation(VONA) to the VAAC to report on ground-basedvolcanic activity whenever they change theAviation Colour Code (ACC; Table 1).The ACC is used by the Civil Aviation Authorityof New Zealand to alert the aviation industry tochanges in the status of volcanoes within thedesignated coverage area (Lechner 2012).

1.3 New Zealand’s Past VAL Systems

In New Zealand, scientists at GNS Science deter-mine the VAL as mandated in the Guide to theNational CDEM Plan (MCDEM 2015a), withconsideration of monitoring data and using theirexperience and knowledge. When decisions needto be made rapidly (e.g., if an eruption has takenplace), the Volcano Duty Officer can make theVAL decision alone. GNS Science, throughGeoNet, communicates this information toMCDEM using Volcanic Alert Bulletins.MCDEM forwards this information on to localauthorities and CDEM Groups through theNational Warning System. GNS Science also dis-seminates this information to other agencies, thepublic, and the media (Scott and Travers 2009).

New Zealand’s first VAL system (known asthe ‘Scientific Alert Level’ or SAL table;

3GeoNet News web page can be found at: http://info.geonet.org.nz/.

Challenges and Benefits of Standardising Early … 609

Table 2) was introduced in 1994. It was designedby local volcanologists, and included descrip-tions for different levels of activity for severaltypes of volcanoes, sometimes within a singlelevel of the table. For example, some levelsincluded descriptions for both unrest and erup-tions. Later this was to cause confusion as peoplewere not sure which description the assignedVAL referred to.

Several teething issues (including mediascrutiny) arose during volcanic unrest at Mt.Ruapehu in late 1994, in part due to theconflicting definitions causing confusion. Theoriginal SAL system was therefore reviewed, anda significantly revised and amended version wasadopted in September 1995, just one week beforethe 1995–96 Mt. Ruapehu eruption episode star-ted. The resulting system (Table 3), renamed asthe VAL system in 2008, was divided into twoseparate sections, one for frequently active vol-canoes, and the other for reawakening volcanoes.In addition to a level for ‘background activity’(VAL 0), the frequently active volcanoes systemincluded one level for unrest (VAL 1) and fourlevels of increasing magnitudes of eruption (VAL2–5), whereas the reawakening volcanoes systemincluded two levels for unrest (VAL 1 and 2) andthree eruption levels (VAL 3–5). The VAL sys-tem was used until it was again revised in 2014.

The division of the VAL system based oneruptive activity was deemed to be beneficialduring the creation of this system because theoutcome of unrest was perceived to be moreuncertain for reawakening volcanoes than fre-quently active volcanoes due to no eruptionsbeing witnessed (except for the 1886 eruption atOkataina). Similarly, calderas (which were pre-dominantly in the reawakening volcanoes group)were seen as more likely to exhibit unrest with-out resulting in an eruption than stratovolcanoes.Many scientists have the perception thatend-users, who are more familiar with strato-volcano eruptions, think unrest will predomi-nantly result in an eruption (Potter 2014). Thus,by separating reawakening volcanoes from fre-quently active volcanoes, it is implied that thevolcanoes behave differently, and that unrest atreawakening volcanoes may not result in an

eruption. An additional level of heightenedunrest was inserted into the reawakening systemto help reinforce this meaning.

2 Reviewing New Zealand’s VALSystems

While the VAL system that was developed in1995 performed well for fifteen years, it under-went an exploratory review between 2010 and2014 to ensure it was the best system possible.Potter et al. (2014) used a qualitative ethnographicmethodology consisting of interviews, observa-tions and document analysis to investigate theVAL system, with the involvement of both sci-entist and end-user groups. For further details onthe methodology and full results of this research,refer to Potter et al. (2014) and Potter (2014).Based on the results of this research, the VALsystem was revised (Fig. 3) and implemented incollaboration with MCDEM on 1 July 2014.

2.1 Standardising Multiple Systemsinto One for All Volcanoes

Many of the research participants identified thedivision between frequently active volcanoes andreawakening volcanoes in the 1995–2014 VALsystem as a concern (Potter 2014). It wasrecognised that the use of two systems:

• Complicated a system that was intended to bea simple communication tool.

• May cause confusion in the future if twovolcanoes exhibiting different levels of sur-face activity were allocated the same VALsystem.

• May cause confusion because as reawakeningvolcanoes become more active they mayswitch sides to become frequently active (andvice versa). This was the case in 2006 whenan eruption occurred at Raoul Island.

It was undefined whether the volcanoes weregrouped according to the time since the lasteruption and/or the recurrence rate of eruptions.

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Other criteria for grouping volcanoes were alsoconsidered. Options identified included groupingvolcanoes by their:

• Type (such as volcanic fields vs. calderas vs.stratovolcanoes)

• Potential size of eruption (however even themost explosive volcanoes predominantlyhave small eruption sizes)

• Tectonic setting (intraplate vs. subduction zone)• Typical risk from an eruption (e.g., Auckland

Volcanic Field vs. Raoul Island)

Table 2 Scientific Alert Level table introduced in 1994 (sourced from Annexe C from the CDEM Plan)

ScientificLevel

Phenomena Observed Scientific Interpretation

1 Abnormal seismic, hydrothermal or other signatures Initial sign of volcano reawakening.No eruption imminent.Possible minor activity

2 Increase in seismic, hydrothermal and other unrestindicators. Increase from usual background weakeruptions

Indicators of intrusion process or significantchange in on-going eruptive activity

3 Relatively high and increasing unrest shown by allindicators.Commencement of minor eruptive activity atreawakening vent(s) or increased vigour of on-goingactivity

If increasing trends continue there is a realpossibility of hazardous eruptive activity

4 Rapid acceleration of unrest indicators. Establishedmagmatic activity at reawakening vents or significantchange to on-going activity

Hazardous volcanic eruption is nowimminent

5 Hazardous volcanic eruption in progress Destruction within the Permanent DangerZone (red zone) and significant risk overwider areas

Table 1 The International Civil Aviation Organization (ICAO) Aviation Colour Code for volcanic activity (ICAO2004)

ICAO ColourCode

Status of activity of volcano

Green Volcano is in normal, non-eruptive state

Or, after a change from a higher alert level:

Volcanic activity considered to have ceased, and volcano reverted to its normal, non-eruptivestate

Yellow Volcano is experiencing signs of elevated unrest above known background levels

Or, after a change from a higher alert level:

Volcanic activity has decreased significantly but continues to be closely monitored for possiblerenewed increase

Orange Volcano is exhibiting heightened unrest with increased likelihood of eruption. Or, volcaniceruption is underway with no or minor ash emission [specify ash-plume height if possible]

Red Eruption is forecasted to be imminent with significant emission of ash into the atmosphere likely

Or, eruption is underway with significant emission of ash into the atmosphere [specify ash-plume height if possible]

Challenges and Benefits of Standardising Early … 611

• Geographical region (or existing VolcanicAdvisory Group).

One VAL system for each volcano was alsoconsidered, with the perceived benefit of beinglocally appropriate. However, this would resultin at least 15 systems in New Zealand, most ofwhich require a response by the same group ofstakeholders and scientists due to the relativelysmall population size and land area, and havingonly one volcano observatory (at GNS Sciencenear the township of Taupo). It is more likely

that having multiple systems in this situation willlead to confusion and mismanagement than in alarger country where separate groups of peopleare responding to the same, familiar volcano overtime. Many participants specifically stated thatthey would not want the over-complication ofhaving too many VAL systems.

The division of volcanoes into separate VALsystems should be considered very carefully. Theneed for the VAL system to be used as a simplecommunication tool very likely outweighs anybenefits of multiple tailored and more detailed

Table 3 New Zealand’s VALS used between 1995 and 2014. Reproduced from the MCDEM (2006) Guide to theNational CDEM Plan, prior to its 2014 revision

612 S.H. Potter et al.

VAL system. For these reasons, the revised VALsystem was designed to be used for all of NewZealand’s volcanoes, regardless of factors suchas the type, setting, frequency of eruptions, ortypical eruption style.

The foundation of the VAL system was alsoexplored in order to determine how the level ofvolcanic activity could best be communicated(Potter et al. 2014). The 1995–2014 VAL systemwas based on the severity of the volcano phe-nomena (e.g., magnitude of eruption); it rangedfrom ‘background activity’ to ‘large hazardouseruption’. The perceived benefits of this foun-dation included:

(a) Scientists were most knowledgeable and“comfortable” in determining the severity ofphenomena, as opposed to considering other

elements of risk. This would lead to lessuncertainty and shorter warning times.

(b) The severity of phenomena was seen as thefirst step in communication, and as beingmore relevant for a wider range of stake-holders. Interpretation and forecasting infor-mation can subsequently be tailored tovarious audiences, environments, and situa-tions in other communication products.

Various other foundations were considered,including: the level of hazard (taking intoaccount the geological and recent eruptive his-tory of a volcano and spatial extent of hazards,but not the exposure and vulnerability of popu-lations); volcano processes and state of theunderlying magma system (ranging from ‘nomagma’ to ‘large extrusion of magma’); the level

Fig. 3 New Zealand’srevised VAL system, whichwas implemented on 1 July2014. Source Sect. 19 of theGuide to the National CDEMPlan (MCDEM 2015a)

Challenges and Benefits of Standardising Early … 613

of risk (taking into account the severity of thehazard as well as the exposure and vulnerabilityof populations); or a combination of factors (e.g.,focussing on the phenomena during unrest andthen on the spatial extent of hazards duringeruptions). Research participants were asked fortheir preference of these options; scientists pre-ferred the phenomena-based system, whilestakeholders were more evenly spread but had aslight preference for a combined foundation.They also suggested other types of VAL systems,particularly retaining a phenomena-based systemthat also included hazard information. As statedby a stakeholder in the CDEM sector:

The phenomenon-based system helps me under-stand what is going on and the relative severity ofthe event. The hazard-based system sets out clearlywhat needs to be done as a consequence. In termsof my CDEM responsibilities, we need both—people get twitchy about instructions given with-out context and justification.

During the final feedback process, this phe-nomena foundation system accompanied byhazard information was found to be useful andacceptable for all of New Zealand’s volcanoes intheir varied risk environments.

2.1.1 Other Considerations WhenStandardising the VALSystem

Very careful consideration was given to allwords in the VAL system (Fig. 3) by its devel-opers (Potter 2014; Potter et al. 2014). Not onlydid it need to be effective during escalation,de-escalation and static levels of volcanic activ-ity, it also needed to be appropriate for the widerange of volcano types and settings in NewZealand. For example, the term ‘vent’ was usedin VAL 3 in the hazard column instead of ‘crater’because some volcanoes have very large craters(e.g., Taupo), or an eruption may occur from avent on a volcano flank. The use of ‘vent’, ‘nearvolcano’ and ‘beyond volcano’ is part of theintroduction of a dimensionless nomenclature tothe VAL system.

No eruption forecasting language was includedin the VAL system (beyond ‘potential for eruptionhazards’ in VAL 2), because the capabilities and

experience of the volcanologists in forecasting ateach of New Zealand’s volcanoes is unequal. Theuse of each phenomena-based alert level would berestricted by the associated description of theexpected future activity, which at some of NewZealand’s volcanoes, will be very uncertain. Forexample, if statements such as ‘eruption expectedwithin the next two weeks’ were included in VAL2, volcanologists would not be able to commu-nicate that a volcano was showing heightenedlevels of unrest unless they also thought that aneruption was expected within the next two weeks.Forecasting information specific to each volcanois instead included in supplementary information,particularly Volcanic Alert Bulletins (VABs).

Because the VAL system needs to be stan-dardised for use at multiple volcanoes, the word-ing needed to be very simple. Therefore, termssuch as ‘minor’, ‘moderate’ and ‘major’ volcaniceruption needed to be defined in order for scien-tists to use the system consistently between vol-canoes, between each other when voting on theVAL, and over time. A GNS Science guidelinedocument has been drafted for this purpose withexamples of typical activity shown at each VALby various volcanoes. This approach was takenrather than describing monitoring criteria thresh-olds (e.g., rate of earthquakes or rate of defor-mation), to ensure the system can be used forevery volcano regardless of its setting, and to givethe scientists more flexibility. A GNS ScienceYouTube video4 was developed to help commu-nicate the typical levels of activity for each of theVAL systems to the public and stakeholders.

3 Lessons Learnt from the NZCase Study in Relationto the Standardisationof VAL System

When considering whether to utilise a standard-ised warning approach, Potter et al. (2014)explored the purpose of the VAL system, theinformation needs of New Zealand’s

4www.youtube.com/watch?v=WeZxW2xyam0&list=UUTL_U_K1eP4T885-JL3rVgw, accessed on 11 May 2017.

614 S.H. Potter et al.

stakeholders, and the capabilities of the volcanomonitoring system. They paid particular attentionto the benefits and challenges of combiningwarning systems for all of the volcanoes intoone. This included determining the foundation ofthe VAL system, the words used in the table,whether forecasting language should be included,and how the system was going to be used con-sistently over time and at multiple volcanoes. Asidentified by the IDNDR Early Warning Pro-gramme Convenors (1997), locally appropriatecommunication methods should be establishedfor the distribution of warnings. The social sci-ence research used for this investigation was arobust process that enabled the revision of theVAL system to be based on evidence, as advo-cated by Leonard and Potter (2015). The result-ing VAL system has been used for all of NewZealand’s volcanoes since June 2014. It hasworked satisfactorily to date. For example, vol-canic unrest or eruptions with which the revisedsystem has been successfully used have included:unrest at Ngauruhoe (VAL raised to 1 and laterlowered); decrease in unrest at Te Maari (VALlowered to 0); and small eruptions at WhiteIsland (VAL raised to 3 and lowered later).Volcanologists at GNS Science have found thesimple descriptions in the revised VAL tablebeneficial for allowing flexible decision-makingwhen determining the level of activity. Havingjust one system for all NZ volcanoes has alsoimproved clarity. Regular evaluations of thiswarning tool will take place in the future,involving stakeholders, volcanologists, and thepublic. There is more monitoring data andinterpretation relevant to end-users and decisionsthan the VAL itself and in New Zealand suchinformation is included in the accompanyingVAB. Based on the recent experiences withreview and implementation of New Zealand’sVAL systems, we strongly recommend stake-holders consider exactly what parameters,impacts, uncertainties and lead-times are impor-tant to each decision that needs to be made (e.g.,evacuation) and not simply tie responses tochanges in the VAL.

The revised VAL system has been developedfor the New Zealand context, including our

volcanic settings and risk environments, the rolesand responsibilities of our agencies, and oursocial and cultural environments including thecentralised nature of our volcano monitoring andwarning system. As such, it is unlikely that it isable to be directly copied for other countries.However, the process that we followed can beused, as summarised in the next section.

4 Recommendations for Reviewingor Developing a VAL System

This chapter has focussed on aspects relating tostandardisation, when reviewing a VAL system.There are other considerations to take intoaccount as well. We describe below our recom-mended processes and considerations whenreviewing a VAL system (or developing a newone), based on our research and experience.

(1) Understand the context

It is vital to understand the physical, cultural,social, organisational and historical context of theVAL and related systems. Potter et al. (2014)found that using the qualitative methodology ofethnography allowed a deep understanding of theculture of the volcanologists to be built to addressmany of the following factors. However, werecognise that this is a time-consuming processthat is not an option for many observatorieslooking to revise their VAL systems. If this is thecase, then drawing on published material, attend-ing volcano monitoring meetings, and holdingdiscussions with those familiar with the variousenvironments should be sufficient. We recommendunderstanding as much as possible about the:

• Range of potential volcanic activity at everyvolcano that the VAL system may be usedfor, including frequency of eruptions, level ofongoing unrest or eruptions, potential mag-nitude of eruptions (and unrest phenomena),and severity of all possible hazards.

• Volcano monitoring system to understandcapabilities and factors such as timing,uncertainties and content of incoming data.

Challenges and Benefits of Standardising Early … 615

• Level of exposure and vulnerability of ele-ments at risk to volcanic hazards, includingthe built, social, economic and naturalenvironments.

• Roles and responsibilities, including legisla-tive requirements, of scientific advisors fromall institutions, and organisations with the roleof planning, education, response and recoveryfrom volcanic events (including governmen-tal and civil defence agencies, infrastructure/lifelines, emergency services, health,agricultural/horticultural and business sec-tors). For example, understand which agen-cies have the responsibility to communicatedirectly to the public.

• Influences on the VAL decision-making pro-cess. This includes understanding the culturesof people/groups determining the VAL sys-tem, and the receivers of the informationincluding decision-makers and stakeholders,and the public. For example, influences on theVAL decision-making process may includeexperience, external pressure, peer pressureand other social psychology biases, internalvoting guidelines, how individuals interpretthe content and structure of the VAL system,and the desire to maintain credibility or con-duct fieldwork (Potter 2014). Factors such asthese contributed towards the design of therevised NZ VAL system. Additionally,understanding the way stakeholders readvolcano-related information and use it in theirdecision-making contributed towards deter-mining what information was included in theNZ VAL system, how it is communicated tothem.

• Previous VAL systems, and any other exist-ing alerting systems for volcanic or otherhazards used in the country or for the volcanoin question. What were people’s experienceswith those systems? What worked well ordidn’t work well? Are there any other warn-ing systems being used on or near the vol-cano, including the international ACC?Understanding VAL systems that have beenimplemented in other parts of the world isalso useful. Being familiar with the chal-lenges and benefits of standardisation as

outlined in this chapter is relevant for thispoint.

• What other communication avenues exist forrelated information from all agencies? Forexample, Volcanic Alert Bulletins, phonecalls, meetings, websites, emails, socialmedia. These provide the context of whetherthe VAL system will need to include allimportant information as a standalone system,or if it can be supported by other channels.

(2) Understand the challenges and benefits of theexisting VAL system

It is important to know who the audience isfor the VAL system, and what they use it for. Ifthe system is targeted at stakeholders anddecision-makers, perhaps more technical andspecific information could be included than if theaudience includes the public. This informationmight also inform the position of the divisionsbetween alert levels by matching it to theirdecision-making needs. However, due to thewide range of stakeholder needs and the differingpoints at which they need to take action, coupledwith a system that communicates to multipleaudiences, it is likely that discussions will needto be held to encourage stakeholders to determinetheir own decision points, rather than themrelying on changes in alert levels. Understandtheir perception of the purpose of the VAL sys-tem, and their experiences with any existingVAL systems, through methods such as inter-views, open-ended questions in surveys, orworkshops/focus groups. Ask the volcanologists(or whomever determines the VAL) what theyfind useful or challenging, and see if their per-ceived purpose of the system matches that of thestakeholders/public. Analyse the existing systemto identify jargon, unclear meanings, and thefoundation of the system. Understand whatchannels are used to communicate it (such aswebsites, social media, Bulletins), as this maypose opportunities or limitations in designing arevised system. Ask all parties what they wouldlike to see in a revised system. Determine factors

616 S.H. Potter et al.

such as whether it should include eruption fore-casting messages, what its foundation should bebased on, and whether it is a standardised systemfor multiple volcanoes, or specific to a singlevolcano.

(3) Produce a draft version of the revised VALsystem and seek feedback

By considering the context, and collating theinformation outlined in step 2, recommendationsfor a revised system can be developed. Based onthose recommendations, a draft version (ormultiple options) can be developed. Both thesummarised findings and the draft(s) can then becirculated back to participants to ensure theirperceptions and needs have been accuratelycaptured. For the NZ revision, Potter (2014)asked participants to rank five draft versions,which helped to determine the most appropriatefoundation and structure of the revised VALsystem. Multiple iterations then occurred toproduce the final version. Do not underestimatethe amount of time needed for this process! Afinal version of the VAL system can now bedeveloped (consider utilising graphicsspecialists).

(4) Release revised system in collaboration withstakeholders

In conjunction with key stakeholders, deter-mine a date on which the new system will beused, taking into account the length of time allparties need to update documentation, websites,etc. Release communications to circulate thechange in VAL system through the media,stakeholder newsletters, meetings, etc. In NZ,GNS Science developed a media release sixweeks prior to the start date of the system, and onthe day of the changeover, with support fromMCDEM. Make a plan for if a new eruptiveepisode should start close to the changeover date(thankfully no eruptions occurred for the chan-geover date in NZ!). Write any supporting doc-umentation or procedures, such as a guideline forconsistent use by the volcanologists, or whether

the VAL system will be used exactly as writtenor more flexibly.

(5) Evaluate the revised VAL System

Conduct regular evaluations to ensure therevised (or new) VAL system is effective, andmeeting the needs of stakeholders, the public,and volcanologists. Real events and exercises canbe used.

5 Volcanic Crisis Communication

Warnings about natural hazard events are com-municated in order to minimise losses (Newhall2000). However, trust and communication net-works must already be in place prior to a crisisfor effective planning and response. This can beachieved by developing networks, ascertaininginformation needs and establishing methods ofeffective communication (Paton et al. 1998).VAL systems are just one aspect of an EWS, andby design are the simplest tool to communicatethe status of the volcano (or level of responserequired, etc.). Due to this overarching purpose,standardising VAL systems can help ensure aconsistent, simple, and understandable design.As we have outlined in this chapter however,there are issues with using a one-size-fits-allcommunication product. This was also identifiedby Thompson et al. (2015) in using probabilisticvolcanic hazard maps. We found that taking intoaccount the local context is vital, which supportsthe findings of numerous recent research in vol-canic crisis communication (Haynes et al. 2007;Fearnley et al. 2012; Potter et al. 2014). Pro-viding supporting information using other meanshelps to alleviate these issues.

Over the past two decades, social science hasincreasingly played a valuable role in mitigatingvolcanic risks by providing evidence-based linksbetween communities, stakeholders and scien-tists (Barclay et al. 2008; Leonard and Potter2015). We recommend that in the future theserobust methodologies are embraced by volcanoobservatories, such as when revising

Challenges and Benefits of Standardising Early … 617

communication strategies and products, to helpeffectively share information and reduce the riskto society.

Acknowledgements The authors would like to thank allresearch participants, supervisors and colleagues for theircontribution to this research. The research was primarilyfunded by the Government of New Zealand through theNatural Hazards Research Platform, and through theEarthquake Commission.

References

Barclay J, Haynes K, Mitchell T, Solana C, Teeuw R,Darnell A, Crosweller HS, Cole P, Pyle D, Lowe C,Fearnley C (2008) Framing volcanic risk communi-cation within disaster risk reduction: finding ways forthe social and physical sciences to work together. GeolSociety Lond Spec Publ 305(1):163–177

Carsell KM, Pingel ND, Ford DT (2004) Quantifying thebenefit of a flood warning system. Nat Hazards Rev5(3):131–140

Davy BW, Caldwell TG (1998) Gravity, magnetic andseismic surveys of the caldera complex, Lake Taupo,North Island, New Zealand. J Volcanol Geoth Res81:69–89

Doyle EEH, Potter SH (2016) Methodology for thedevelopment of a probability translation table forGeoNet. GNS Science report 2015/67. GNS Science,Lower Hutt, New Zealand, p 18

Doyle EE, Johnston DM, McClure J, Paton D (2011) Thecommunication of uncertain scientific advice duringnatural hazard events. NZ J Psychol 40(4):39–50

Druce AP (1966) Tree-ring dating of recent volcanic ashand lapilli, Mt Egmont. NZ J Bot 4(1):3–41

Fearnley CJ (2011) Standardising the USGS volcano alertlevel system: acting in the context of risk, uncertaintyand complexity. Ph.D thesis, University CollegeLondon, London, UK

Fearnley CJ (2013) Assigning a volcano alert level:negotiating uncertainty, risk, and complexity indecision-making processes. Enviro Plan A 45(8):1891–1911

Fearnley CJ, McGuire WJ, Davies G, Twigg J (2012)Standardisation of the USGS Volcano Alert LevelSystem (VALS): analysis and ramifications. Bull Volc74(9):2023–2036

Garcia C, Fearnley CJ (2012) Evaluating critical links inearly warning systems for natural hazards. EnvironHazards 11(2):123–137

Gardner CA, Guffanti MC (2006) U.S. geologicalsurvey’s alert notification system for volcanic activity.U.S. Geological Survey Fact Sheet 2006–3139. U SGeol Surv

GNS Science, The Ministry of Civil Defence andEmergency Management (2015) Memorandum ofunderstanding between the Ministry of Civil Defence

& Emergency Management (MCDEM) and Instituteof Geological and Nuclear Sciences Limited (GNSScience) for the engagement of geoscience and CivilDefence Emergency Management. pp 18

Guffanti MC, Miller TP (2013) A volcanic activityalert-level system for aviation: review of its develop-ment and application in Alaska. Nat Hazards 69:1519–1533. doi:10.1007/s11069-013-0761-4

Haynes K, Barclay J, Pidgeon N (2007) Volcanic hazardcommunication using maps: an evaluation of theireffectiveness. Bull Volc 70(2):123–138. doi:10.1007/s00445-007-0124-7

Hogg A, Lowe DJ, Palmer J, Boswijk G, Ramsey CB(2012) Revised calendar date for the Taupo eruptionderived by 14C wiggle-matching using a New Zealandkauri 14C calibration data set. Holocene 22(4):439–449

Hurst AW, McGinty PJ (1999) Earthquake swarms to thewest of Mt Ruapehu preceding its 1995 eruption.J Volcanol Geoth Res 90(1–2):19–28

ICAO (2004) Handbook on the International AirwaysVolcano Watch (IAVW). Doc 9766-AN/968: Interna-tional Civil Aviation Organization (ICAO)

IDNDR early warning programme convenors (1997)Guiding principles for effective early warning. Con-venors of the international expert groups on earlywarning. United nations international decade fornatural disaster reduction, Geneva, Switzerland

Kear D, Thompson BN (1964) Volcanic risk in North-land. NZ J Geol Geophys 7(1):87–93

Lechner P (2012) Living with volcanic ash episodes incivil aviation: the New Zealand Volcanic Ash Advi-sory System (VAAS) and the International AirwaysVolcano Watch (IAVW) Civil Aviation Authority ofNew Zealand

Leonard G, Potter S (2015) Developing effective com-munication tools for volcanic hazards in New Zealand,using social science. In: Loughlin SC, Sparks S,Brown SK, Jenkins SF, Vye-Brown C (eds) Globalvolcanic hazards and risk. Cambridge UniversityPress, Cambridge, UK, pp 305–310

Leonard GS, Johnston DM, Paton D, Christianson A,Becker J, Keys H (2008) Developing effective warn-ing systems: ongoing research at Ruapehu volcano,New Zealand. J Volcanol Geoth Res 172(3–4):199–215. doi:10.1016/j.jvolgeores.2007.12.008

Leonard GS, Stewart C, Wilson TM, Procter JN, Scott BJ,Keys HJ, Jolly GE, Wardman JB, Cronin SJ,McBride SK (2014) Integrating multidisciplinaryscience, modelling and impact data into evolving,syn-event volcanic hazard mapping and communica-tion: a case study from the 2012 Tongariro eruptioncrisis, New Zealand. J Volcanol Geoth Res 286:208–232. doi:10.1016/j.jvolgeores.2014.08.018

Lindsay J, Marzocchi W, Jolly G, Constantinescu R,Selva J, Sandri L (2010) Towards real-time eruptionforecasting in the Auckland Volcanic Field: applica-tion of BET_EF during the New Zealand nationaldisaster exercise ‘Ruaumoko’. Bull Volc 72(2):185–204. doi:10.1007/s00445-009-0311-9

618 S.H. Potter et al.

Maskrey MA (1997) IDNDR Secretariat, Geneva, Oct1997

MCDEM (2015a) The guide to the National CivilDefence Emergency Management Plan 2015. Ministryof Civil Defence & Emergency Management,Wellington. Retrieved from http://www.civildefence.govt.nz/assets/guide-to-the-national-cdem-plan/Guide-to-the-National-CDEM-Plan-2015.pdf

MCDEM (2015b) National Civil Defence EmergencyManagement plan order 2015. (2015/140) Ministry ofCivil Defence and Emergency Management,NewZealand. Retrieved from http://www.legislation.govt.nz/regulation/public/2015/0140/latest/DLM6486453.html?src=qs%20

Mileti DS, Sorensen JH (1990) Communication ofemergency public warnings—a social science per-spective and state-of-the-art assessment. Laboratory,Oak Ridge National, p 166

Nairn IA (2002) Geology of the Okataina VolcanicCentre. Geological map 25, scale 1:50 000, 1sheet + 156p. Institute of Geological & NuclearSciences Limited, Lower Hutt

Nairn IA, Houghton BF, Cole JW (1991) Volcanichazards at White Island. Volcanic hazards informationseries, vol 3. Ministry of Civil Defence

Neall VE (2003) The volcanic history of Taranaki.Massey University, Palmerston North, New Zealand,Institute of Natural Resources

Neall VE, Alloway BV (1996) Volcanic hazards atEgmont Volcano; volcanic hazard map of westernTaranaki. Volcanic hazards information series, vol 12.Occasional Report. Massey University, New Zealand

Needham AJ, Lindsay JM, Smith IEM, Augustinus P,Shane PA (2011) Sequential eruption of alkaline andsub-alkaline magmas from a small monogeneticvolcano in the Auckland Volcanic Field, NewZealand. J Volcanol Geoth Res 201(1–4):126–142.doi:10.1016/j.jvolgeores.2010.07.017

Newhall CG (2000) Volcano warnings. In: Sigurdsson H,Houghton BF, McNutt SR, Rymer H, Stix J(eds) Encyclopedia of Volcanoes. Academic Press,San Diego, CA, pp 1185–1197

Paton D, Johnston DM, Houghton B (1998) Organisa-tional response to a volcanic eruption. Disaster PrevManage 7(1):5–13

Platz T (2007) Aspects of dome-forming eruptions fromandesitic volcanoes through the Maero EruptivePeriod (1000 yrs B.P. to present): activity at Mt.Taranaki, New Zealand. Ph.D thesis, Massey Univer-sity, Palmerston North, New Zealand

Potter SH (2014) Communicating the status of volcanicactivity in New Zealand, with specific application tocaldera unrest. Ph.D thesis, Massey University,Wellington, New Zealand. Retrieved from http://mro.massey.ac.nz/handle/10179/5654

Potter SH, Scott BJ, Jolly GE (2012) Caldera unrestmanagement sourcebook. GNS Science Report2012/12. GNS Science, Lower Hutt, New Zealand,p 73

Potter SH, Jolly GE, Neall VE, Johnston DM, Scott BJ(2014) Communicating the status of volcanic activity:revising New Zealand’s volcanic alert level system.J Appl Volcanol 3(13)

Potter SH, Scott BJ, Jolly GE, Johnston DM, Neall VE(2015) A catalogue of caldera unrest at TaupoVolcanic Centre, New Zealand, using the VolcanicUnrest Index (VUI). Bull Volc 77:78. doi:10.1007/s00445-015-0956-5

Scott BJ (1978) Volcano and geothermal observations1977: observed activity at Ngauruhoe. New ZealandVolcanological Record (pp 44–45): NZ Geol Surv,DSIR

Scott BJ, Nairn IA (1998) Volcanic hazards: Okatainavolcanic centre. Scale 1:100,000: Bay of PlentyRegional Council. Resource planningpublication/Bay of Plenty Regional Council, NewZealand 97/4

Scott BJ, Potter SH (2014) Aspects of historical eruptiveactivity and volcanic unrest at Mt. Tongariro, NewZealand: 1846–2013. J Volcanol Geoth Res 286(Special issue: Tongariro Eruption 2012):263–276

Scott BJ, Travers J (2009) Volcano monitoring in NZ andlinks to SW Pacific via the Wellington VAAC. NatHazards 51(2):263–273. doi:10.1007/s11069-009-9354-7

Self S (2006) The effects and consequences of very largeexplosive volcanic eruptions. Philos Trans R Soc AMath Phys Eng Sci 364(1845):2073–2097. doi:10.1098/rsta.2006.1814

Smith IEM, Okada T, Itaya T, Black PM (1993) Agerelationships and tectonic implications of late Ceno-zoic basaltic volcanism in Northland, New Zealand.NZ J Geol Geophys 36(3):385–393

Thompson MA, Lindsay JM, Gaillard JC (2015) Theinfluence of probabilistic volcanic hazard map prop-erties on hazard communication. J Appl Volcanol4(1):1–24

UN ISDR (2003) Terminology: basic terms of disasterrisk reduction retrieved 25/08/2009, from http://www.unisdr.org/eng/library/lib-terminology-eng%20home.htm

United Nations (2006) Global survey of early warningsystems. Final Version. 46 p. http://www.unisdr.org/2006/ppew/info-resources/ewc3/Global-Survey-of-Early-Warning-Systems.pdf (accessed 20 March2010)

Wilson CJN (1993) Stratigraphy, chronology, styles anddynamics of late quaternary eruptions from Taupovolcano, New Zealand. Philos Trans Phys Sci Eng 343(1668):205–306

Wilson CJN, Walker GPL (1985) The Taupo eruption,New Zealand I. General aspects. Philosophical Trans-actions of the Royal Society of London. Ser A MathPhys Sci 314(1529):199–228

Wilson CJN, Rogan AM, Smith IEM, Northey DJ,Nairn IA, Houghton BF (1984) Caldera volcanoes ofthe Taupo Volcanic Zone. J Geophys Res 89(B10):8463–8484

Challenges and Benefits of Standardising Early … 619

Wilson CJN, Houghton BF, McWilliams MO, Lan-phere MA, Weaver SD, Briggs RM (1995) Volcanicand structural evolution of Taupo Volcanic Zone, NewZealand—a review. J Volcanol Geoth Res 68(1–3):1–28

Wilson CJN, Gravley DM, Leonard GS, Rowland JV(2009) Volcanism in the central Taupo Volcanic Zone,New Zealand: tempo, styles and controls. Studies inVolcanology: the legacy of george walker. Spec publIAVCEI 2:225–247

Wilson T, Stewart C, Sword-Daniels V, Leonard GS,Johnston DM, Cole JW, Wardman J, Wilson GJ,

Barnard ST (2012) Volcanic ash impacts on criticalinfrastructure. Phys Chem Earth Parts A/B/C 45–46:5–23

Wilson T, Stewart C, Wardman JB, Wilson G, John-ston DM, Hill D, Hampton SJ, Villemure M,McBride S, Leonard G (2014) Volcanic ashfallpreparedness poster series: a collaborative processfor reducing the vulnerability of critical infrastructure.J Appl Volcanol 3(1):1–25

Winson AE, Costa F, Newhall CG, Woo G (2014) Ananalysis of the issuance of volcanic alert levels duringvolcanic crises. J Appl Volcanol 3(1):14

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