Earthquake early warning:Adding societal value to regional

networks and station clusters

Richard Allen, UC BerkeleySeismological Laboratory

rallen@berkeley.edu

Sustaining funding for regional seismic networks is hard

– exciting scientific questions can motivate a new network

Earthquake early warning is one such capability/product

– long-term sustained funding requires broader societal buy-in

capabilities/products that are valued by society

capabilities/products that are updated/available regularly

Key points

Recent scientific advances and technological developments now makeearthquake early warning possible

Early warning systems are being developed and implemented around theworld

Active systems: Japan, Taiwan, Turkey, Mexico, Romania

Test system in CA accurately predicted the ground shaking in San Franciscobefore it was felt for the Alum Rock earthquake

Warning systems could provide additional societal value to any seismicnetwork in earthquake prone regions

Simple “in town” station clusters could provide a few seconds warning

Regional network systems could provide tens of seconds warning

High earthquake fatality rates occur due to poor/rudimentary construction

Many of these buildings are single story

Only takes a few seconds to get out

What is early warning?

1. Rapid detection of an earthquake in progress 2. Rapid notification of observed ground shaking 3. Prediction and notification of future ground shaking

Goal: to provide warning prior to damaging ground shaking

Current realtimeearthquake information:

Post earthquake

“ShakeMap”

Map of observed groundshaking available 7-10minutes after an event

What is early warning?

1. Rapid detection of an earthquake in progress 2. Rapid notification of observed ground shaking 3. Prediction and notification of future ground shaking

Goal: to provide warning prior to damaging ground shaking

AlertMap0 sec

AlertMap+2 sec

ShakeMap+ minutes

Continuum of earthquake information:1. Detection 2. Rapid magnitude,

ground shakingprediction

3. Post earthquakeinformation

ElarmS-RT

Real-time implementationof ElarmS in California

OperationalOctober 10th, 2007

P-wave methodology:using first arrivingenergy to maximizewarning time

ElarmS-RT

Alum Rockearthquake8:04pm Tue Oct 30th, 2007Mw 5.4

ElarmS-RT AlertMap

ElarmS AlertMap

Alum Rock earthquakeOctober 30, 2007

Mw 5.4

detection 20:04:59

ElarmS-RT AlertMap

CISN ShakeMap

Alum Rock earthquakeOctober 30, 2007

Mw 5.4

ElarmS AlertMap

detection +1 sec Mag: 5.2 ΔMMI: 0.1 ± 0.6

ElarmS-RT AlertMap

CISN ShakeMap

Alum Rock earthquakeOctober 30, 2007

Mw 5.4

ElarmS AlertMap

detection +2 sec Mag: 5.8 ΔMMI: -0.1 ± 0.5

ElarmS-RT AlertMap

CISN ShakeMap

Alum Rock earthquakeOctober 30, 2007

Mw 5.4

ElarmS AlertMap

detection +3 sec Mag: 5.9 ΔMMI: 0.1 ± 0.6

ElarmS-RT Performance – Alum Rock earthquake

origintime

San Joseshakes Oakland

shakes

0 +5 +10 +15 +20 sec

San Franciscoshakes

epicenterSan Jose

OaklandSan Francisco

ElarmS-RT Performance – Alum Rock earthquake

origintime

San Joseshakes Oakland

shakes

0 +5 +10 +15 +20 sec

San Franciscoshakes

P-wave reachesseismometers

ElarmS-RTdetection

1st AlertMap2nd 3rd

15 sec telemetry delay

ElarmS-RT Performance – Alum Rock earthquake

origintime

San Joseshakes Oakland

shakes

0 +5 +10 +15 +20 sec

San Franciscoshakes

ElarmS-RTdetection

1st AlertMap2nd 3rd

15 sec telemetry delay

+150

1st

AlertMaps2nd 3rd

+5 +10 +20 sec

10+ secwarning

ElarmS-RTdetection

Oaklandshakes

San Franciscoshakes

Potential

15 sec telemetry delay

Potential 1 sec ?

Warning timesfor San Francisco

• Existing stations

• Telemetry upgrade

• From “Alarm” time (4 sec of data at 4 stations)

Range of warningtimes: 0 to 1 min

Warning times

• 20 sec warningfor San Franciscoand Oakland

Loma Prietaearthquake

• 10 sec warningfor San Franciscoand Oakland

Alum Rockearthquake

at the Moscone Center

Range of warningtimes: 0 to 1 min

Loma Prieta

ABAG ground shaking

Oakland 66% fatalities

San Francisco 18% fatalities

Cypress viaduct collapse

Falling masonry

Apartmentbuilding collapse

84% of the fatalities were atdistances which could have

received 20 sec warning

Earthquake early warning

JapanTaiwan

Mexico

Turkey

Romania

Italy

Greece

India

UnitedStates

Operational systemsSystems under developmentaround the world

around the worldCurrent applications of early warning

Istanbul

• Electric power plant

• High rise building (bank)

Taiwan

• Rail system

• Hospital

Mexico and Oaxaca Cities users

• Private industry 28• Schools 84• Housing complex 1• TV/Radio stations 34• Government offices 94• Subway 4

Japan

• Rail/Metro systems

• Fire/rescue organizations

• In home information;door/window opening;utility shut-off

• Elevator control

• Outdoor works

• Factories

• Power plants

• Hospitals

GSHAP

S-wave

P-wave

Warning system designsLocation of seismic network: End-member 1: in the earthquake source region

fault

SeismicStations

S-wave

P-wave

Warning system designs

fault

SeismicStations

Location of seismic network: End-member 1: in the earthquake source region

S-wave

P-wave

Warning system designs

fault

SeismicStations

Warning time is proportional to thedistance from the sensor to town

50 km ~10 sec warning100 km ~30 sec warning200 km ~50 sec warning

Location of seismic network: End-member 1: in the earthquake source region

Mexico City: Seismic Alert System

• Developed in 1989 in thewake of the 1985Michoacan earthquake

• 15 stations along coast

• Station data transmittedto central processing inMexico City

• Warning issued whentwo stations indicate anevent greater thanmagnitude 5

• ~300 km allows 60+ secwarning

300 km

“Front detection”

Guerrero earthquakeSeptember 14, 1995

• magnitude 7.3

• event successfullydetected and analert issued

• 72 sec warning

• no real damage inMexico City

S-wave

P-wave

Warning system designs

SeismicStations

Location of seismic network: End-member 1: in the earthquake source region End-member 2: in town

Why 4-5 stations?

Testing in California showsthat waiting for 4-5 stationdetections prevents almostall false alarms

S-wave

P-wave

Warning system designs

SeismicStations

Location of seismic network: End-member 1: in the earthquake source region End-member 2: in town

Warning time is dependent on theP-to-S time

50 km 2-3 sec warning100 km ~8 sec warning200 km ~18 sec warning

S-wave

P-wave

Warning system designs

fault

SeismicStations

Location of seismic network: End-member 1: in the earthquake source region End-member 2: in town Hybrid: around town

S-wave

P-wave

Warning system designs

fault

SeismicStations

Location of seismic network: End-member 1: in the earthquake source region End-member 2: in town Hybrid: around town

S-wave

P-wave

Warning system designs

fault

SeismicStations

Location of seismic network: End-member 1: in the earthquake source region End-member 2: in town Hybrid: around town

S-wave

P-wave

Warning system designs

fault

SeismicStations

Location of seismic network: End-member 1: in the earthquake source region End-member 2: in town Hybrid: around town

Pakistan 2005

Islamabad

Muzaffarabad

Uri

M 7.6

80,000 fatalities– poor construction– many single story buildings

Pakistan 2005

Muzaffarabad: Regional capitol20 km from epicenter50% buildings destroyed

Warning time: P-to-S: ~3 secS-arrival: 6.5 sec best case 1-2 sec warning

Pakistan 2005

Uri: 60 km from epicenter80% of buildings destroyed

Warning time: P-to-S: 7.5 sec ~4 sec warningS-arrival: 18 sec 10+ sec warning

Pakistan 2005

Islamabad : 105 km from epicenter Warning time: P-to-S: 12 sec 8 sec warning

S-arrival: 28 sec 20+ sec warning

Bam

M 6.6

Iran 2003

Bam: 12 km from epicenter Warning time: P-to-S: 1.5 sec

S-arrival: 4 sec no warning

Peru 2007

Pisco: 68,000 people80% buildings destroyed50 km from epicenter

Warning time: P-to-S: 6 sec 3 sec warningS-arrival: 15 sec 10 sec warning

M 8.0

Pisco

Peru 2007

Ica: 120,000 people50% buildings destroyed115 km from epicenter

Warning time: P-to-S: 16 sec 10 sec warningS-arrival: 35 sec 30 sec warning

M 8.0

Ica

Warning time

• Few seconds for “in town”station clusters

• Tens of seconds for regionalnetworks

High impact

• Poor/rudimentaryconstruction results inhigh fatality rates

• Evacuation possible in afew seconds

Summary

• There is rapid development and implementationof early warning around the world

• Adding a warning capability to seismic networksadds societal value

ElarmS workshop

More information at…

UC Berkeley

May 5-16, 2008

Week 1: Lectures and exercises to familiarize participantswith the methodology and code

Week 2: Assist participants to get the code running back intheir home institutions

Participants need to be self-supporting

Contact: rallen@berkeley.edu

Different approaches for different timescalesMitigating seismic hazard

Decades: Probabilistic seismic shaking hazard

building codes and land use regulation

Few years: Hazard information and education

individual and community awareness and preparedness

Months to hours: Prediction of the time and location of an earthquake

Not possible in the foreseeable future

Seconds to minutes: Earthquake warning systems

Rapid detection of earthquake, prediction and warning of shaking

Months to hours: Prediction of the time and location of an earthquake

Not possible in the foreseeable future