Causes of Explosive Basaltic

Volcanism in the 2001

Eruption of Mount Etna,

Sicily

Student No. 339860

2

Student No. 339860

Contents

1.0 Abstract ................................................................................................................................ 2

2.0 Introduction .......................................................................................................................... 3

3.0 Background .......................................................................................................................... 7

3.1 Structural Setting ............................................................................................................. 7

3.2 Local Setting .................................................................................................................... 8

3.3 Volcanic Evolution ........................................................................................................ 10

4.0 Overview of the 2001 Eruption.......................................................................................... 12

4.1 Geochemical Results for Erupted Products ................................................................... 14

5.0 Discussion .......................................................................................................................... 15

5.1.First Stage (19-24 July) .............................................................................................. 15

5.2 Second Stage (24-25 July) ......................................................................................... 16

5.3 Third Stage (25th

July – 1st August) ........................................................................... 17

5.4 Fourth Stage (1st-6

th August) ...................................................................................... 17

6.0 Conclusions ........................................................................................................................ 19

References ................................................................................................................................ 19

1.0 Abstract

This paper attempts to better understand the chronology, processes and products involved in

the explosive ash-forming events of the July-August 2001 eccentric eruption at Mount Etna,

Sicily. A literature review, coupled with analysis of geochemical results published in recent

journal articles, has been combined to answer these questions. The findings are therefore used

to elucidate the stance on the events involved, with four stages defined to represent the

aforementioned objectives. Stage 1 is considered to involve phreatomagmatic activity; Stage

2 represents a transitional stage towards Strombolian events; Stage 3 wholly involves

Strombolian activity; whilst Stage 4 is considered indicative of Vulcanian activity.

3

Student No. 339860

2.0 Introduction

Situated on the eastern coast of Sicily (Fig. 1), Mount Etna is a stratovolcano, rising to a

height of some 3330m a.s.l and dominating the lives of more than 2 million people (Kilburn

& McGuire, 2001, p. 115), including Catania, Sicily’s second largest city (Fig. 2).

Etna’s activity has long been thought of as mild, typified by lava flows, fire fountaining and

mild Strombolian activity from both summit craters and parasitic vents. Chester et al. (1985,

p. 17) noted that in historical times (up to 1985) violent activity had been rare, with the

exception of the 1979 eruption, which generated enough ash to disrupt population centres to

the east and southeast, including Catania’s Fontanarossa airport.

The 2001 eruption (Fig. 3) represents one of the most explosive events in living memory,

which included the release of juvenile ash, predominantly of 0.4 to 1mm in diameter, with a

plume height of 5km a.s.l. (Taddeucci, Pompilio, & Scarlato, 2004, p. 33). Accompanying

ash falls trended in an E and SE direction (Figure 9) and were recorded as far away as

Cefalonia, Greece, 500km from the eruption site, reaching the island just 24 hours after the

eruption (Dellino & Kyriakopoulos, 2003, p. 341). Involving both lateral and eccentric

eruptions simultaneously (Andronico, Cristaldi, Del Carlo, & Taddeucci, 2009; Behncke &

Neri, 2003; Coltelli, Miraglia, & Scollo, 2008; Corsaro, Miraglia, & Pompilio, 2007; Dellino

& Kyriakopoulos, 2003; Lanzafame, Neri, Acocella, Billi, Funiciello, & Giordano, 2003;

Metrich, Allard, Spilliaert, Andronico, & Burton, 2004; Neri, Acocella, Behncke, Maiolino,

Ursino, & Velardita, 2005; Scollo, Del Carlo, & Coltelli, 2007; Taddeucci, Pompilio, &

Scarlato, 2004; Viccaro, Ferlito, Cortesogno, Cristofolini, & Gaggero, 2006) it may be

considered that this could pave the way for future violent eruptions such as that of 2002-03.

Much has been written and documented specifically on both the surface and subsurface

processes and the eruptive products of the July 2001 event. However, it is not considered that

a great degree of agreement has been forthcoming between authors on the processes involved

in the eccentric eruption, with different hypotheses on the processes involved in the

production of tephra during this eruption type. This could represent a number of serious flaws

in the accuracy of the overall understanding of the hazards represented by this eruption,

potentially leading to incorrect analysis of any similar future eruptions (such as 2002-03), and

the hazards posed to the Mount Etna region. It is therefore the aim of this report to: (1)

outline the timescale of violent basaltic events of the 2001 Etnean eruption, as considered by

4

Student No. 339860

Behncke and Neri (2003); (2) identify the products involved; and (3) discuss the processes

involved in the formation of these products, by means of a literature review.

Figure 1: Location of Mount Etna in relation to other volcanic centres in Italy. Inset: location of the

main population centres on Etna’s flanks. Modified from Chester, Duncan, & Dibben (2008, p. 218).

5

Student No. 339860

Figure 2: Populations of the main towns and cities of the Etna region in 1985. (After Chester et al

1985, p.60).

6

Student No. 339860

Figure 3: Map of the eruptive fissures and lava flows during the 2001 July-August eruption of Etna.

(Scollo, Del Carlo, & Coltelli, 2007, p. 148)

7

Student No. 339860

3.0 Background

3.1 Structural Setting

The tectonic history of Eastern Sicily is greatly complex (Figure 4), chiefly governed by the

collision of the Eurasian and African plates, comprising the opening and closing of the Ionian

Sea, and the subduction, bending and possible compression of the Aeolian-Calabrian arc

(Scarth & Tanguy, 2001, p. 55; Patane, Agostino, La Delfa, & Leonardi, 2009, p. 307). As

subduction neared an end, thrusting of the Eurasian plate over the African plate occurred,

forming the Appeninic-Maghrebian mountain chain situated to the west of the volcano

(Barberi, Civetta, Gasparini, Innocenti, Scandone, & Villari, 1974, p. 123; Catalano, Torrisi,

& Ferlito, 2004, p. 315). As a result of this, the Tyrrehnian part of Sicily is under contraction,

whilst the Ionian side is under extension (Lanzafame, Neri, Acocella, Billi, Funiciello, &

Giordano, 2003).

Figure 4: The main regional tectonic features of Mount Etna identifying the compressive domain to

the west, considered to be a result of Africa-Europe plate collision, and the tensional domain of the

Calabrian Arc Appeninic to the east (Barberi, Cocina, Neri, Privitera, & Spampinato, 2000, p. 319).

8

Student No. 339860

3.2 Local Setting

The collision of the African and Eurasian plates, as well as more complex regionalised

structural patterns, has resulted in distinct rift zones (Figure 4) which has allowed magma to

move laterally and radially away from the volcano’s more centrally-located vertical to sub-

vertical network of dikes (Rust, Behncke, Neri, & Ciocanel, 2005, p. 141), producing flank

eruptions at distances greater than 10km from the central craters.

Several hypotheses have been put forward for Etna’s volcanic formation. Tanguy,

Condomines, & Kieffer (1997, p. 239) have proposed a hot-spot theory, which has been

backed up by the 3He/

4He ratio of olivine phenocrysts in lavas having remained steady

throughout the volcano’s history, and suggests the sub-continental lithosphere as the single

source feeding Etnean magmas (Clocchiatti, Schiano, Ottolini, & Bottazzi, 1998, p. 399).

This theory involves the presence of a mantle diapir resulting from a localised high strain in

the lithosphere, which acts as a heat flow channel (Tanguy, Condomines, & Kieffer, 1997, p.

239).

A ‘slab-window’ theory has been suggested by (Doglioni, Innocenti, & Mariotti, 2001, p. 25).

This considers a vertical slab window, causeed by the rollback of the Ionian lithosphere,

which allowed for alkali magmatism beneath Etna. The area of rollback is thought to occur

along the Malta escarpment, between Sicily and the Ionian Sea (Patane, La Delfa, & Tanguy,

2006, p. 832), with this feavily faulted zone of the volcano allowing the percolation of

magma through the host rock, to the surface.

9

Student No. 339860

Figure 4: Map identifying the main North and South - and, to a lesser extent – West rift zones of the

volcano. The main eruptive fractures and parasitic cones are also denoted (after- Crisci, Iovine, Di

Gregorio, & Lupiano, 2008). Key: 1. Eruptive fracture; 2. Parasitic cone; 3. Volcanics; 4.

Sedimentary basement.

10

Student No. 339860

Figure 5: A simplified cartoon of the tectonic evolution of the eastern Sicily-Ionian Sea transition,

and related emplacement of Mount Etna along theactive right-lateral transtensional fault, resulting

from the theory of differential rollback in the footwall of teh accretionary wedge. Modified from

Doglioni, Innocenti, & Mariotti, (2001).

3.3 Volcanic Evolution

Reasonably accurate documentation over the last 400 years of Etna’s eruptive activity has

been used to better understand the pattern of volcanic behaviour from historic eruptions

(Tanguy, Kieffer, & Patane, 1996, p. 259). Indications from this data are that effusive activity

is dominant, with lava flows and Strombolian activity from active centres. However, more

recent eruptions – particularly in 2001 – indicates a further stage of evolution with more

explosive eruptions and the emission of, at times, two compositionally distinct magmas (Neri,

Acocella, Behncke, Maiolino, Ursino, & Velardita, 2005, p. 253), and voluminous ash

emissions. Consequently, Tanguy, Condomines & Kieffer (1997, p. 247) indicate the activity

of eruptions previous to 1997 were a result of “subtle interactions” between mantle diapirism,

the development of a permanent deep magma reservoir at a depth of 20-30km, and temporary

shallow chambers allowing crystal fractination (Figure 6).

11

Student No. 339860

Figure 6: A schematic representation of the magmatic and structural evolution of Mount Etna,

modified from Tanguy, Condomines, & Kieffer (1997, p. 245). Arrows inducate the movement in the

mantle and resulting tensional stresses in the crust. Note the change in scale from early magma

evolution in the asthenosphere, to present day. Porphyritic trachybasalts have formed where magma

ponding occurs at shallower depths, whilst aphyric trachybasalts are erupted directly from a deep

chamber.

12

Student No. 339860

4.0 Overview of the 2001 Eruption

The eruption was characterised by an initial paroxysmal fire fountaining event located at the

Southeast Crater on the 13th

July 2001 (Viccaro, Ferlito, Cortesogno, Cristofolini, &

Gaggero, 2006, p. 141), followed, days later, by seven separate lava flows – two originating

from vents on the Southeast Crater, and five erupting from vents on five separate newly-

formed fissure systems on the southern flank (Behncke & Neri, 2003, p. 465). Whilst lava

flows were ongoing explosive activity in the form of two end-member, predominantly ash-

forming events, and a transitional Strombolian and fire fountaining (Metrich, Allard,

Spilliaert, Andronico, & Burton, 2004, p. 3) phase took place. These explosive products were

almost exclusively formed at one fissure system locted at an elevation of 2570m in an area

known as the “Piano del Lago” (Behncke & Neri, 2003, p. 466; Corsaro, Miraglia, &

Pompilio, 2007, p. 402; Viccaro, Ferlito, Cortesogno, Cristofolini, & Gaggero, 2006, p. 141).

Lava flows ceased on the 9th

August 2001 (Behncke & Neri, 2003, p. 466), marking the end

of the eruption.

A brief chronology of the explosive eruptive activity and products produced from the Piano

del Lago fissure system is outlined in Table 1, with an isopach map of the first ash event in

Figure 7. The geochemical composition of lavas and ash are defined in Table 2 and Figure 8.

Stage Start Date End Date Products Notes

1 19/07/20011 24/07/2001

1 Ash & Lapilli

1

200-300m high pyroclastic

column1,4

2 24/07/20011 25/07/2001

1

Lava fountaining2,3,4

Ash,

Lapilli & Scoria

Up to 500m high4

3 25/07/20011 01/08/2001

1

Lava fountaining3,4

and

Scoria2,3

100-120m high scoria cone

formed1,3,4

Lava flowed

from vent at base of cone

from 26th to 1st August1,3

4 01/08/20011,3

06/08/20013

Ash & dense non-vesicular

blocks3

Pulsing ash explosions up to

5km high1,3

Progressively

diminishing until 6th

August1

Table 1: An overview of the explosive activity observed at the Piano del Lago fissure system during

the 2001 eruption, compiled from data available from 1: Behncke & Neri (2003); 2: Metrich et al

(2004); 3: Taddeucci, Pompilio & Scaroato (2004); 4: Viccaro et al (2006).

13

Student No. 339860

Figure 7: Isomass map of the tephra deposits formed between 21-24 July 2001. Curves are given in

kg m-2

, with coordinates in UTM-Datum ED50. From Scollo, Del Carlo, & Coltelli (2007, p. 152).

14

Student No. 339860

4.1 Geochemical Results for Erupted Products

Eruption

Type

Plagioclase

(%) Clinopyroxene (%) P.I Index (%)

Lateral 16-23% 10-19% 33-40%

Eccentric 5-7% 8-13% 18-22%

Table 2: Comparison of plagioclase, clinopyroxene and Porphyricity Index (P.I.) of Lateral and

Eccentric lavas from the 2001 eruption using data gathered by Corsaro, Miraglia, & Pompilio (2007,

p. 403).

Figure 8: Daily componentry of the airborne ash collected during the 2001 eruption, modified from

Taddeucci, Pompilio, & Scarlato (2004, p. 40). The numbers to the right indicate 1: Ash and lapilli

stage; 2: Lava fountaining and scoria stage; 3: Ash and block stage.

15

Student No. 339860

5.0 Discussion

For the purpose of this section each of the four events, as described in Table 1, will be

considered separately.

5.1 First Stage (19-24 July)

As mentioned in Table 1 the explosive products of this phase were predominantly ash and

Lapilli, as attested by the proximal section in Fig. 7. Taddeucci et al (2004, p. 40) indicated

that these ash particles were sideromelane rich, although it should also be noted that a large

proportion of lithics were incorporated during this stage relative to the other stages (Fig. 8).

The same authors also suggest that, throughout the whole period of the eruptive events

(Stages 1-4) emission rates were at an intermediate level during this stage.

It is considered by Behncke and Neri (2003, p. 465) that visual evidence of continuous

“uprush” and “tephra-finger” activity of the pyroclastic column points to phreatomagmatic

activity. This is backed up by evidence of a high lithic content during this stage (Table 1),

which is considered to represent a high energy event, such as phreatomagmatic activity

(Houghton & Smith, 1993, p. 414).

It was previously considered by Chester et al. (1985, p. 139) that such activity was unlikely at

Mount Etna, and that any activity would be “limited”. However, evidence of previous

phreatomagmatic eruptive activity at Etna is considered in the 18.7 ka flank eruption at Etna

(Andronico, Branca, & Del Carlo, 2001, p. 235). Whilst this historic eruption was at an

elevation of 800m a.s.l. where impermeable Pleistocene clays are located (Andronico et al.

2001, p. 235), no such deposits are considered to exist at the level of the 2001 eruption

(2570m). In this instance, where only volcanic products exist, the presence of a shallow

impermeable ash layer (of unknown depth) beneath the Piano Del Lago, inferred by Behncke

and Neri (2003, p. 472) seems the most plausible location for groundwater to pond, especially

as the same authors consider meltwater to collect at this location following each winter.

It is widely accepted by authors (Andronico, Cristaldi, Del Carlo, & Taddeucci, 2009;

Behncke & Neri, 2003; Corsaro, Miraglia, & Pompilio, 2007; Dellino & Kyriakopoulos,

2003; Guest, Cole, Duncan, & Chester, 2003, p. 199; Lanzafame, Neri, Acocella, Billi,

Funiciello, & Giordano, 2003; Metrich, Allard, Spilliaert, Andronico, & Burton, 2004; Neri,

Acocella, Behncke, Maiolino, Ursino, & Velardita, 2005; Patane, La Delfa, & Tanguy, 2006;

Taddeucci, Pompilio, & Scarlato, 2004; Viccaro, Ferlito, Cortesogno, Cristofolini, &

16

Student No. 339860

Gaggero, 2006.) that an eccentric dike cut through this shallow aquifer, allowing magma-

water interaction. This has also occurred at a number of other basaltic volcanoes, most

notably Surtsey, but also including (but not limited to) Taupo Volcanic Centre (Wilson &

Smith, 1985, p. 329), Crater Hill, New Zealand (Houghton, Wilson, & Smith, 1999, p. 119),

Croscat, Garrotxa Volcanic Field (Di Traglia, Cimarelli, de Rita, & Gimeno Torrente, 2009,

p. 89), Fontana, Nicaragua (Costantini, Houghton, & Bonadonna, In Press) the Canary

Islands (Clarke, Troll, & Carracedo, 2009, p. 226) and the Prebble and Mawson Formations,

Antarctica (Elliot & Hanson, 2001, p. 183). In such magma-water interactions, it is not

considered that the chemistry of the magma is an important factor in the explosivity of the

eruption compared other variables such as the depth of the interaction and the amount of

water made available.

5.2 Second Stage (24-25 July)

Characterised by a mixture of ash, lapilli, fire fountaining and scoria production (Table 1) this

activity was marked by decreasing lithic ejecta and increasing Sideromelane (Figure 8). It is

considered that this stage is characteristic of an transitional phase between the first

(phreatomagmatic stage) and the third stage, indicated by the waning of phreatomagmatic

activity (Behncke & Neri, 2003, p. 472) and a change to gradually increasing lava

fountaining and scoria production (Taddeucci, Pompilio, & Scarlato, 2004, p. 35; Viccaro,

Ferlito, Cortesogno, Cristofolini, & Gaggero, 2006, p. 142).

In order for a change in events it is considered that magma-water interaction must have been

reduced in one of three ways: 1) All of the groundwater was consumed; 2) the fragmentation

level of the magma rose above the watertable (Behncke & Neri, 2003, p. 472); 3) An increase

in emission rates of the magma allowed the conduit to seal itself, preventing water interaction

(Taddeucci, Pompilio, & Scarlato, 2004, p. 52).

Behncke & Neri (2003, p. 473) consider the first point to be unlikely, because of their

hypothesis that phreatomagmatic activity occurred at Stage 4, and therefore consider the

second option. They noted that when ejection angles were low (with magma high in conduit)

activity moved from phreatomagatic to Strombolian and vica verca. However, more recent

evidence suggests that the underlying eccentrically located magma was volatile rich and

microlite (crystal) poor ((Table 2) (Clocchiatti, Condomines, Guenot, & Tanguy, 2004, p.

397; Taddeucci, Pompilio, & Scarlato, 2004, p. 37)). This increase in volatiles, whilst being

17

Student No. 339860

microlite poor and therefore of a lower viscosity, would suggest a more rapid ascent,

contributable to the theory of an increased emission rate. It can be hypothesised that whilst

this magma was more volatile rich, the low crystal content of the magma allowed a

significant portion of the volatiles to readily exsolve from the magma, resulting in

Strombolian activity.

5.3 Third Stage (25th

July – 1st August)

It is considered that the third stage is marked by the complete transition of activity to dry

magmatic eruptions, with a reduction of lithic fragments within ash samples and an increase

in sideromelane content (Fig. 8), leading to predominantly lava fountaining and scoria cone

production over ash-forming events (Behncke & Neri, 2003, p. 465). Over the coming days it

is noted that a more tachylite-rich ash with a greater crystal content was erupted on the 30th

July to the 1st August, at the end of this third stage (Fig. 8).

The trend towards more tachylite-rich erupted products suggests the presence of magma

mixing at depth (Taddeucci, Pompilio, & Scarlato, 2004, p. 52). A greater crystal content of

the magma suggests that it had a residence time greater than the previously erupted magma,

allowing crystallisation and loss of volatiles either through this process, or by slower

migration due to the higher viscosity attributable to crystallisation. This hypothesis agrees

with that of Clocchiatti et al. (2004, p. 411), Taddeucci, Pompili & Scarlato (2004, p. 53) and

Viccaro et. al (2006, p. 156).

5.4 Fourth Stage (1st-6

th August)

This stage was marked by the eruption of block and ash deposits (Table 1) and coincides with

the almost complete replacement of sideromelane ash with tachylite ash (Figure 8). It has

been considered by Behncke & Neri (2003, p.466) that this activity marks a final

phreatomagmatic phase. However, this stage was marked by a much higher eruption column

of 5km a.s.l. (Taddeucci, Pompilio, & Scarlato, 2004, p. 33), with Dellino and Kyriakopoulos

(2003, p. 341) noting that ash falls occurred as far away (500km) as Cefalonia, Greece. These

observations suggest that different mechanisms may have been involved.

Combined with evidence from the ash componentry (deficient in lithics), it is not considered

that this phase involved water-magma interaction, or that, at the very least this was not the

main cause of the eruption style. However, Dellino and Kyriakopoulos (2003 p. 342), in

assessing ash fall at large distances, identified stepped features, considered to relate to melt-

18

Student No. 339860

fragmentation in a brittle mode, known to occur during magma-water interaction. The same

authors noted that the glass particles showed blocky textures with few isolated vesicles of

spherical form (2003, p. 342), suggesting that exsolution and expansion did not play a major

role in the eruptive dynamics.

It is hypothesised that the final stage, dominated by ash pulsations (Taddeucci, Pompilio, &

Scarlato, 2004, p. 33), is related to the ingress of this new tachylite- and crystal-rich magma

into the conduit system, which, owing to its higher viscosity, is assumed to have ascended at

a slower rate relative to the previous magma. Slow ascent would allow the magma to degas,

reducing the fragmentation potential. This contradicts the hypothesis posed by Clocchiatti et.

al. (2004, p. 411) who consider the high explosivity to be a result of this magma moving from

a minimum depth of 30km below the volcano to mix with the eccentrically erupting magma

within the space of a few months, as inferred from 210

Pb-226

Ra disequilibria, and hence a high

emission rate. However, a high emission rate was not observed during this final stage

according to Taddeucci, Pompilio & Scarlato, 2004, p.52).

It is considered that a combination of these aforementioned events led to the voluminous ash

production event. With low effusion rates of this final phase magma it is considered that

voluminous and pulsating ash production could not have occurred. Instead, it is proposed that

a deep magma ascended relatively rapidly, possibly through a network of dikes, to mix with

the eccentrically erupting magma. Ascent was slowed at depth where mixing of the two

magmas occurred due to the presence of the original, now more viscous (higher microlite

content) magma, resulting in degassing of this new magma body. It is then considered that

the hypothesis of Taddeucci, Pompilio & Scarlato (2004, p. 53) fits well, whereby a plug of

this combined, microlite-rich magma – with a high yield strength and high liquid and bulk

viscosities – prevents the upward migration of magma. Ash pulsations are therefore produced

when the build up of volatiles from the degassing magma, collecting beneath this plug,

exceed the plug’s strength, causing Vulcanian behaviour.

This is not considered to represent the first time an Etnean ash-forming event has occurred in

this way, with the Plinian eruption of 122BC thought to have involved increased viscosity

caused by microlites (Sable, Houghton, Del Carlo, & Coltelli, 2006, p. 351). Other basaltic

volcanoes, such as Fontana, Nicaragua (Costantini, Houghton, & Bonadonna, In Press) and

Tarawera in 1886 (Houghton, Wilson, Del Carlo, Coltelli, Sable, & Carey, 2004, p. 12) have

acted similarly in the past.

19

Student No. 339860

6.0 Conclusions

The 2001 eccentric explosive basaltic eruption is considered to be representative of the

following stages:

1) Initial phreatomagmatic activity (19th

-24th

July, 2001), caused by the intrusion of

magma into a shallow aquifer, creating a 200-300m high eruption column which

dispersed predominantly ash and Lapilli with a high lithic content.

2) Transition from phreatomagmatic to Strombolian activity (24th

-25th

July, 2001),

resulting from an increase in the emissivity of a volatile- and sideromelane-rich, but

microlite poor magma.

3) Strombolian activity (25th

July to 1st August, 2001) through the continued ascent of

the magma involved in stage 2.

4) Vulcanian activity (1st-6

th August, 2001) resulting in a 5km a.s.l. tephra column,

forming block and ash deposits. It is considered that this activity was caused by a

more tachylite- and mircrolite-rich magma essentially plugging the conduit. Pulsing

ash and block events are therefore produced when the strength of the magma plug is

exceeded by the strength of degassing volatiles from the underlying magma.

References

Andronico, D., Branca, S., & Del Carlo, P. (2001). The 18.7 ka phreatomagmatic flank

eruption on Etna (Italy): relationship between eruptive activity and sedimentary basement

setting. Terra Nova , 13, 235-240.

Andronico, D., Cristaldi, A., Del Carlo, P., & Taddeucci, J. (2009). Shifting styles of basaltic

explosive activity during the 2002-03 eruption of Mt. Etna, Italy. Journal of Volcanology and

Geothermal Research , 180, 110-122.

Barberi, F., Civetta, L., Gasparini, P., Innocenti, F., Scandone, R., & Villari, L. (1974).

Evolution of a section of the Africa/Europe plate boundary: paleomagnetic and

volcanological evidence from Sicily. Earth and Planetary Science Letters , 22, 123-132.

Barberi, G., Cocina, O., Neri, G., Privitera, E., & Spampinato, S. (2000). Volcanological

inferences from seismic-strain tensor computations at Mt. Etna Volcano, Sicily. Bulletin of

Volcanology , 62, 318-330.

Behncke, B., & Neri, M. (2003). The July-August 2001 eruption of Mt. Etna (Sicily). Bulletin

of Volcanology , 65, 461-476.

Catalano, S., Torrisi, S., & Ferlito, C. (2004). The relationship between Late Quaternary

deformation and volcanism of Mt. Etna (eastern Sicily): new evidence from the sedimentary

20

Student No. 339860

substratum in the Catania region. Journal of Volcanology and Geothermal Research , 132,

311-334.

Chester, D., Duncan, A., & Dibben, C. (2008). The importance of religion in shaping

volcanic risk perception in Italy, with special reference to Vesuvius and Etna. Journal of

Volcanology and Geothermal Research , 172, 216-228.

Chester, D., Duncan, A., Guest, J., & Kilburn, C. (1985). Mount Etna, The Anatomy of a

Volcano. London: Chapman and Hall Ltd.

Clarke, H., Troll, V., & Carracedo, J.-C. (2009). Phreatomagmatic to Strombolian eruptive

activity of basaltic cinder cones: Montana Los Erales, Tenerife, Canary Islands. Journal of

Volcanology and Geothermal Research , 180, 225-245.

Clocchiatti, R., Condomines, M., Guenot, N., & Tanguy, J.-C. (2004). Magma changes at

Mount Etna: the 2001 and 2002-2003 eruptions. Earth and Planetary Science Letters , 226,

397-414.

Clocchiatti, R., Schiano, P., Ottolini, L., & Bottazzi, P. (1998). Earlier alkaline and

transitional magmatic pulsation of Mt. etna volcano. Earth and Planetary Science Letters ,

163, 399-407.

Coltelli, M., Miraglia, L., & Scollo, S. (2008). Characterization of shape and terminal

velocity of tephra particles erupted during the 2002 eruption of Etna volcano, Italy. Bulletin

of Volcanology , 70, 1103-1102.

Corsaro, R., Miraglia, L., & Pompilio, M. (2007). Petrologic evidence of a complex plumbing

system feeding the July-August 2001 eruption of Mt. Etna, Sicily, Italy. Bulletin of

Volcanology , 69, 401-421.

Costantini, L., Houghton, B., & Bonadonna, C. (In Press). Constraints on eruption dynamics

of basaltic explosive activity derived from chemical and microtextural study: The example of

teh Fontana Lapilli Plinian eruption, Nicaragua. Journal of Volcanology and Geothermal

research .

Crisci, G., Iovine, G., Di Gregorio, S., & Lupiano, V. (2008). Lava-flow hazard on the SE

flank of Mt. Etna. Journal of Volcanology and Geothermal Research , 177, 778-796.

Dellino, P., & Kyriakopoulos, K. (2003). Phreatomagmatic ash from the ongoing eruption of

Etna reaching the Greek island of Cefalonia. Journal of Volcanology and Geothermal

Research , 126, 341-345.

Di Traglia, F., Cimarelli, C., de Rita, D., & Gimeno Torrente, D. (2009). Changing eruptive

styles in basaltic explosive volcanism: Examples from Croscat complex scoria cone, Garrotxa

Volcanic Field (NE Iberian Peninsula). Journal of volcanology and Geothermal Research ,

180, 89-109.

Doglioni, C., Innocenti, F., & Mariotti, G. (2001). Why Mt Etna? Terra Nova , 13, 25-31.

21

Student No. 339860

Elliot, D., & Hanson, R. (2001). Origin of widespread, exceptionally thick basaltic

phreatomagmatic tuff breccia in the Middle Jurassic Prebble and Mawson Formations,

Antarctica. Journal of Volcanology and Geothermal Research , 111, 183-201.

Guest, J., Cole, P., Duncan, A., & Chester, D. (2003). Volcanoes of Southern Italy. Bath: The

Geological society.

Houghton, B., & Smith, R. (1993). Recycling of magmatic clasts during explosive eruptions:

estimating the true juvenile content of phreatomagmatic volcanic deposits. Bulletin of

Volcanology , 55, 414-420.

Houghton, B., Wilson, C., & Smith, I. (1999). Shallow-seated controls on styles of explosive

basaltic volcanism: a case study from New zealand. Journal of Volcanology and Geothermal

Research , 91, 97-120.

Houghton, B., Wilson, C., Del Carlo, P., Coltelli, M., Sable, J., & Carey, R. (2004). The

influence of conduit processes on changes in style of basaltic Plinian eruptions: Tarawera

1886 and Etna 122BC. Journal of Volcanology and Geothermal Research , 137, 1-14.

Kilburn, C., & McGuire, W. (2001). Italian Volcanoes. Harpenden: Terra Publishing.

Lanzafame, G., Neri, M., Acocella, V., Billi, A., Funiciello, R., & Giordano, G. (2003).

Structural features of the July-August 2001 Mount Etna eruption: evidence for a complex

magma supply system. Journal of the Geological Society , 160, 531-544.

Metrich, N., Allard, P., Spilliaert, N., Andronico, D., & Burton, M. (2004). 2001 flank

eruption of the alkali- and volatile-rich primitive basalt responsible for Mount Etna's

evolution in the last three decades. Earth and Planetary Science Letters , 228, 1-17.

Neri, M., Acocella, V., Behncke, B., Maiolino, V., Ursino, A., & Velardita, R. (2005).

Contrasting triggering mechanisms of the 2001 and 2002-2003 eruptions of Mount Etna

(Italy). Journal of Volcanology and Geothermal Research , 144, 235-255.

Patane, G., Agostino, I., La Delfa, S., & Leonardi, R. (2009). Evolution of volcanism around

the eastern sector of Mt. Etna, inland and offshore, in the structural framework of eastern

Sicily. Physics of the Earth and Planetary Interiors , 173, 306-316.

Patane, G., La Delfa, S., & Tanguy, J.-C. (2006). Volcanism and Mantle-crust Evolution: The

Etna case. Earth and Planetary Science Letters , 241, 831-843.

Rust, D., Behncke, B., Neri, M., & Ciocanel, A. (2005). Nested zones of instability in the

Mount Etna volcanic edifice, Italy. Journal of Volcanology and Geothermal Research , 144,

137-153.

Sable, J., Houghton, B., Del Carlo, P., & Coltelli, M. (2006). Changing conditions of magma

ascent and fragmentation during the Etna 122 BC basaltic Plinian eruption: Evidence from

clast microtextures. Journal of Volcanology and Geothermal Research , 158, 333-354.

22

Student No. 339860

Scarth, A., & Tanguy, J.-C. (2001). Volcanoes of Europe. Harpenden, England: Terra

Publishing.

Scollo, S., Del Carlo, P., & Coltelli, M. (2007). Tephra Fallout of the 2001 Etna flank

eruption: Analysis of the deposit and plume dispersal. Journal of Volcanology and

Geothermal Research , 160, 147-164.

Taddeucci, J., Pompilio, M., & Scarlato, P. (2004). Conduit processes during the July-August

2001 explosive activity of Mt. Etna (Italy): inferences from glass chemistry and crystal size

distribution of ash particles. Journal of Volcanology and Geothermal Research , 137, 33-54.

Tanguy, J.-C., Condomines, M., & Kieffer, G. (1997). Evoulution of the Mount Etna magma:

Constraints on the present feeding system and eruptive mechanism. Journal of Volcanology

and Geothermal Research , 75, 221-251.

Tanguy, J.-C., Kieffer, G., & Patane, G. (1996). Dynamics, lava volume and effusion rate

during the 1991-1993 eruption of Mount Etna. Journal of Volcanology and Geothermal

Research , 71, 259-265.

Viccaro, M., Ferlito, C., Cortesogno, L., Cristofolini, R., & Gaggero, L. (2006). Magma

mixing during the 2001 event at Mount Etna (Italy): Effects on the eruptive dynamics.

Journal of Volcanology and Geothermal Research , 149, 139-159.

Wilson, C., & Smith, I. (1985). A basaltic phreatomagmatic eruptive centre at Acacia Bay,

Taupo Volcanic Centre. Journal of the Royal Society of New Zealand , 15, 329-337.