The next big earthquake at SFO (coming soon) Tom Brocher USGS, Coordinator, NC Earthquake Hazard...
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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?
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
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
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).
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.
Putting Down Roots in
Earthquake Country
Secure your family and your residence.
A guide for preparing for the next big 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?