geologic hazards and space geodesy

part 4: integrating GPS into warning and response

Can we design a better tsunami alert system?

Reduce false alarms don’t cause panic; educate people on how to react

Warn everybody - needs to be in the right language Broadcast

Radio TV Satellite telecommunication Cell phone GPS

Sirens or Loudspeakers? One can trigger the next so as to propagate the alarm rapidly (not backwards, don’t want to jam comm’s with a back-propagating notification)

Buoy system can directly notify and propagate alert signal through satellite and all other telecomm links immediately

Airplane, blimp or helicopter with loudspeakers or sign towed behind it?

Can we design a better tsunami evacuation, safety and survival system? (some of the solutions need to work even for

very low-lying islands and other coastal plain areas)

Underground bunker (waterproof hatches like a submarine) Strong tall buildings with extra capacity stairwells for people to

run up very quickly to higher levels where it’s safe, and lots of emergency supplies, water and food stored up high Could have a big red flashing light and siren on top

Boats with large capacity that can launch quickly and get out into deep water very fast

Airplanes with large capacity that can get airborne quickly Helicopters with tremendous lifting capacity so that they can

sling-load many people to safe high ground, load after load Special roads heading straight to high ground, which could have

special high-capacity cars to move quickly and make many trips back and forth to shuttle many people

Basic warning elements

• Know an event happened as fast as possible

• Know the location of an event

• Know the size of an event

• Know the probability that an event produced a tsunami

Pre-earthquake:

Reference static displacementReference static rotationMean and variance of dynamic characteristics

During earthquake:

Changes in dynamic characteristicsHysteretic behaviorDamage initiation

Post-earthquake:

Permanent static displacementPermanent static rotationMean and variance of dynamic characteristics

Multiple sensor package:• Acceleration / Velocity• Displacement (GPS)• Rotation (tilt-meter)

AUTOMATED TAGGING AND REAL-TIME DAMAGE DISTRIBUTION MAPS

LinearNonlinear

Permanentdisplacement

FRC.

DISP.

Automated Tagging and Real-Time Damage Distribution Maps

GPS real-time displacement

1-Hz data

Caltech Tectonic Observatory GPS Array

GPS buoy systems

• NOAA DART buoys are expensive and high maintenance

• GPS can be used for large numbers of low-cost buoys to complement existing system

• NavCom-AXYS contract for US Navy (NAVOCEANO); 2 cm inshore, 10 cm offshore

• NOAA-USGS testing program for warning application

• Tie in with existing earthquake and weather monitoring and alerts

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Other data sets

Basic response elements

• Know the location of damage

• Know the extent of damage

• Know the type of damage and therefore the response required

GPS results

• GPS surveys before and after the earthquake are differenced to obtain 3D vectors of permanent deformation (courtesy of CESS, SEIRES)

• Deformation data are modeled to obtain slip on the fault plane, especially in areas complementary to seismology

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Bilham et al., in press SRL

Remote sensing

• (a) Pre-earthquake and (b) post-earthquake Advanced Space-borne Thermal Emission and Reflection Radiometer (ASTER) images of North Sentinel Island, showing emergence of the coral reef surrounding the island. (c) Pre-earthquake and (d) post-earthquake ASTER images of a small island off the northwest coast of Rutland Island, 38 km east of North Sentinel Island, showing submergence of the coral reef surrounding the island. The “pivot line” must run between North Sentinel and Rutland islands. Note that the scale for the North Sentinel Island images differs from that for the Rutland Island images. Scale bars as follows: left (a-b) 0-6 km; right (c-d) 0-1 km. (ASTER images courtesy of NASA/JPL from Meltzner et al., 2006).

What do GPS and Before & After images tell us?

• Derive damage assessment maps:– Indicate areas most severely affected by shaking & inundation

– Provide rapid and comprehensive information needed in support of decisions on prioritization for resource deployment

– Help with vital logistical aspects of relief efforts (e.g., Can ports be used for shipping? Are bridges knocked out? Where are survivors?)

• Validate & verify rapidly estimated finite-fault slip models (e.g., predicted vs. observed coastal uplift & submergence)

– provide important input data to refine fault source models

• Tsunami inundation map data as input to tsunami propagation models• Flood data to assess saline infiltration and damage to irrigable lands and water

supplies; is flooding permanent or transient?• Commercial and other imagery and analysis tools have reached a new level of

utility with recent disaster responses– still require calibration, ground-truthing, validation, and algorithm & software

development

– promising for future rapid assessment & quantification

Prototype GPS fault slip sensor; up to 10 Hz

Spans the San Andreas fault near Gorman, California

California

San Andreas - instrument majorlifeline infrastructure crossings

Cajon Pass I-15 Fault Crossing

California