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The disastrous Sumatra-Andaman earthquake of 26 December 2004 was one of the largest ever recorded. The damage potential of such earthquakes depends on the extent and magnitude of fault slip. The first reliable moment magnitude estimate of 9.0 was obtained several hours after the Sumatra-Andaman earthquake, but more recent, longer-period, normal-mode(More)
We compare the source time functions (i.e., moment release rates) of three large California mainshocks with the seismic moment release rates during their aftershock sequences. After-shock moment release rates, computed by summing aftershock moments in time intervals, follow a power-law time dependence similar to Omori's law from minutes to months after the(More)
The observation of foreshocks preceding large earthquakes and the suggestion that foreshocks have specific properties that may be used to distinguish them from other earthquakes have raised the hope that large earthquakes may be predictable. Among proposed anomalous properties are the larger proportion than normal of large versus small foreshocks, the power(More)
[1] The discovery of non‐volcanic tremor (NVT) has opened a new window to observe major Earth plate boundaries. However, the spectral characteristics of NVT have not been well studied due to poor signal‐ to‐noise ratio (SNR) on individual seismograms. We estimate the spectral content of Cascadia tremor between 2.5 and 20 Hz by suppressing noise using array(More)
The time history of energy release during earthquakes illuminates the process of failure, which remains enigmatic for events deeper than about 100 kilometers. Stacks of teleseismic records from regional arrays for 122 intermediate (depths of 100 to 350 kilometers) and deep (depths of 350 to 700 kilometers) earthquakes show that the temporal pattern of(More)
4. Previously we showed that fault zones heal 5 , and here we have shown that the combination of shaking and static stress reduces the modulus of a recently broken fault zone. This probably indicates that the strength of the fault was reduced, which could trigger earthquakes. Our observation thus may provide a direct measurement of the missing connection(More)
1 SUMMARY. We compare the source time functions (moment release rates) of three large California mainshocks with the seismic moment release rates during their aftershock sequences. Aftershock m o m e n t release rates, computed by summing aftershock moments in time intervals, follow Omori's law from minutes to months after the mainshockk furthermore, in(More)
Technical Abstract We determined orientations of principal stresses around the San Andreas Fault (SAF) system in the greater San Francisco Bay Area and regions further north along the strike-slip plate boundary. Stress orientations, as well as a ratio between stress magnitudes, were determined by inversions of approximately 6000 earthquake fault plane(More)
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