Ch 3: Characterization of the SFBR Earthquake

SourcesWorking Group on California

Earthquake Probabilities, 2002

Overview

Fault SegmentationRupture Sources &

ScenariosGeologic Slip RatesPrevious EarthquakesFault Area

Area covered by report

Fault Segments

the shortest section considered capable of repeatedly rupturing to produce large earthquakes

criteria: kinematic & dynamickinematic: geometry, structuredynamic: rupture length, displacement

of previous eqs, timing, changes in slip/creep rates, microearthquakes

Ruptures

rupture source: single or combination of adjacent fault segments; floating eq

rupture scenario: combination of rupture sources that describe mode of failure of the entire fault during one eq cycle

rupture model: weighted combinations of the fault-rupture scenarios

Hayward-Rogers Creek Segments

140 km long 3 segments: 9±2

RC: 8.4±2, 235-387 HN: 10±1, 270-710 HS: 7-10, 150-250 N,

130±40 S Tule Pond creep 4-6

change in timing constraint from previous reports

Rupture Model Construction

San Andreas Segments

~260

~300

~150

San Gregorio Segments

Calaveras Fault Segments

Green Valley & Concord Faults

Greenville Fault Segments

Segment Dimensions

Follow-up Papers Segall, P., and Lisowski, M., 1990, Surface displacements in the 1906 San

Francisco and 1989 Loma Prieta earthquakes: Science, v. 250, no. 4985, p. 1241-1244.

Schwartz, D.P., Pantosti, D., Okumura, K., Powers, T., and Hamilton, J., 1998, Paleoseismic investigations in the Santa Cruz Mountains: Implications for the recurrence of large magnitude earthquakes on the San Andreas Fault: Journal of Geophysical Research, v. 103, p. 17,985-18,001.

Thatcher, W., Marshall, G., and Lisowski, M., 1997, Resolution of fault slip along the 470-km- long rupture of the great 1906 San Francisco earthquake: Journal of Geophysical Research, v. 102, no. B3, p. 5353-5367.

Lettis, W., 2001, Late Holocene behavior and seismogenic potential of the Hayward-Rodgers- Creek fault system in the San Francisco Bay area, California: Calif. Geol. Surv. Bulletin, v. 210, p. 167-178.

C. Goldfinger et al., Rupture lengths and temporal history of significant earthquakes on the offshore and north coast segments of the Northern San Andreas Fault based on turbidite stratigraphy, Earth Planet. Sci. Lett. (2006).