Mr. Leonardo Seeber
Earth Institute Contact: Mr. Leonardo Seeber
Locations: United States of America
The main purpose of this research is to further test our preliminary observation that the temporal decay of earthquakes triggered by shear versus normal stress change are distinct. We also wish to pursue the hypothesis that a poroelastic response of small faults can account for this behavior. We plan to expand the Encourage-Discourage approach we have developed (Seeber and Armbruster, 2000) by including a poroelastic response to a change in the stress component normal to the fault. We will apply this approach to aftershock sequences in California, including the 1994 Northridge sequence, and on updated sets of hypocenters, focal mechanisms, and their interpretation into slip planes (Seeber and Armbruster, 2000). We also wish to compare results in Southern California with the 19992000 earthquake sequence on the North Anatolian fault in Turkey. We have developed a high-resolution data set for that sequence by combining data from our deployment (Seeber et al., 2000) with data of several other groups. Most of the 33,812 hypocenters in Figure 2B, including 3700 reliable focal mechanisms, are based on 23 stations within the area of that figure. This area is centered at the juncture of the Izmit Mw7.4 Aug 17 rupture on the west and the Duzce Mw7.2 Nov 10 rupture on the east. Figure 2A shows the temporal behavior of the seismicity: Note the change in slope of the Duzce aftershock decay at about day 335 and compare with the similar behavior in the Landers sequence (Figure 1A).
Cross Cutting Themes:
Hazards and Risk
Southern California Earthquake Center (SCEC)