The next big earthquake at SFO (coming soon) Tom Brocher USGS, Coordinator, NC Earthquake Hazard...

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big earthquake at SFO (coming soon) Tom Brocher USGS, Coordinator, NC Earthquake Hazard Investigations http:// earthquake.usgs.gov/ M7 1868 Hayward quake

Transcript of The next big earthquake at SFO (coming soon) Tom Brocher USGS, Coordinator, NC Earthquake Hazard...

The next big earthquake at SFO (coming

soon)

Tom BrocherUSGS, Coordinator,

NC Earthquake Hazard Investigations

http://earthquake.usgs.gov/

M7 1868 Hayward quake

Example from M5.4 Alum Rock earthquake on the Calaveras

Fault

Recent M5.6 earthquake on the Calaveras Fault- this was only a moderate size quake - it wasn’t the Big One!

~64,000 responses to Did You Feel It?

45 seconds of strong shaking

The really big one (M7.8)!

Almost none of the San Francisco Peninsula was developed in 1906

San Mateo

Millbrae

S. San Francisco

Daly City

S. F.

Palo Alto

Redwood CityHalf Moon Bay

Belmont

Pacifica

27%

21%

10%

11%

4%

3%

3%

In the next 30 years there is a 62%, nearly 2 in 3 chance, of a magnitude 6.7 or greater earthquake in the greater Bay Area. Hazard is highest in the East Bay due to the larger number of faults there, and due to the Hayward Fault, which has a high hazard.

SEVEN DEADLY FAULTS

Ground shaking levels from the 1906 quake

USGS, 2005

1989 Loma Prieta

1906 quake

Loma Prieta was NOT the big one for Millbrae!30 Loma Prieta Earthquakes = 1906 Earthquake

San Mateo

Millbrae

Millbrae

1868 Hayward1868 HaywardEarthquakeEarthquake

““the great San the great San Francisco Francisco

earthquake”earthquake”

Shaking intensities Shaking intensities were strong from were strong from San Leandro south San Leandro south through Hayward through Hayward towards Alvaradotowards Alvarado

They were weaker They were weaker in Oakland andin Oakland andMission San JoseMission San Jose

SFO

M6.7 to M7 1868 Hayward earthquake

• 30 fatalities, 5 in San Francisco (12th most deadly US earthquake)

• $350,000 in damage in San Francisco alone

• Extensive damage in San Leandro, Hayward, and Fremont

Bancroft Library

HaywardsHotel

Edmunson Warehouse

Hayward was heavily damaged by the 1868 earthquake. “Practically not a house was left on its foundations…” “Many buildings were much damaged.” (Lawson Report, 1908).

Bancroft Library

Reinstein Clothing Factory, 314 California St.

Settlement

Will Cause the Most Damage

Apartments over a garage: Soft-story, corner building collapse (Marina)

House over a garage: Soft-story collapse Santa Cruz Mountains

1989

Communications will be lost

KGO Radio Towers

M6.9 1989 Loma Prieta

quake

Cellphones won’t work (didn’t work last month)

Built 1937

The local geology makes a huge difference in how the ground shakes. Loma Prieta recordings from 1989.

Water and gas mains broken

1906 quake

USGS OFR 2006-1037

SFO

Port of SF

I-280

I-280

101

101

92

San Andreas Fault

A recent USGS map

? ?

?

?

?SAF

HF

1989 Favorable Fire Conditions

Marina fire

Part of San Francisco burned in 1906

Lifelines/Infrastructure

Putting Down Roots in

Earthquake Country

Secure your family and your residence.

A guide for preparing for the next big quake.

ShakeMap

Was available 15 minutes after the earthquake.

Useful for recovery assessment.

Example from M5.4 Alum Rock earthquake on the Calaveras

Fault

Recent M5.6 earthquake on the Calaveras Fault- this was only a moderate size quake - it wasn’t the Big One!

~64,000 responses to Did You Feel It?

http://1868alliance.org/

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