scholarly journals Estimation of seismic moment and slip distribution of the April 1, 1946, Aleutian tsunami earthquake

1997 ◽  
Vol 102 (B6) ◽  
pp. 11765-11774 ◽  
Author(s):  
Jean M. Johnson ◽  
Kenji Satake
Keyword(s):  
Seismic Moment ◽  
Slip Distribution ◽  
Tsunami Earthquake

scholarly journals Detailed analysis of tsunami waveforms generated by the 1946 Aleutian tsunami earthquake

2001 ◽  
Vol 1 (4) ◽  
pp. 171-175 ◽  
Author(s):  
Y. Tanioka ◽  
T. Seno
Keyword(s):  
Seismic Moment ◽  
Seismic Waves ◽  
Boussinesq Equation ◽  
Fault Model ◽  
Japan Trench ◽  
Tsunami Generation ◽  
Tide Gauges ◽  
Tsunami Waveforms ◽  
Tsunami Earthquake ◽  
20 Nm

Abstract. The 1946 Aleutian earthquake was a typical tsunami earthquake which generated abnormally larger tsunami than expected from its seismic waves. Previously, Johnson and Satake (1997) estimated the fault model of this earthquake using the tsunami waveforms observed at tide gauges. However, they did not model the second pulse of the tsunami at Honolulu although that was much larger than the first pulse. In this paper, we numerically computed the tsunami waveforms using the linear Boussinesq equation to determine the fault model which explains the observed tsunami waveforms including the large second pulse observed at Honolulu. The estimated fault width is 40–60 km which is much narrower than the fault widths of the typical great underthrust earthquakes, the 1957 Aleutian and the 1964 Alasuka earthquakes. A previous study of the 1896 Sanriku earthquake, another typical tsunami earthquake, suggested that the additional uplift of the sediments near the Japan Trench had a large effect on the tsunami generation. In this study, we also show that the additional uplift of the sediments near the trench, due to a large coseismic horizon-tal movement of the backstop, had a significant effect on the tsunami generation of the 1946 Aleutian earthquake. The estimated seismic moment of the 1946 Aleutian earthquake is 17–19 × 1020 20 Nm (Mw 8.1).

Three-dimensional finite-difference modeling of the San Andreas fault: Source parameterization and ground-motion levels

1998 ◽  
Vol 88 (4) ◽  
pp. 881-897
Author(s):  
Robert W. Graves
Keyword(s):  
Los Angeles ◽  
Ground Motion ◽  
Rise Time ◽  
Seismic Moment ◽  
Slip Distribution ◽  
Los Angeles Basin ◽  
Near Fault ◽  
Long Period ◽  
San Andreas ◽  
Fault Region

Abstract Olsen et al. (1995) recently simulated an Mw 7.75 earthquake on the San Andreas fault, predicting long-period (T > 2.5 sec) ground velocities of 140 cm/sec in the Los Angeles basin, about 60 km from the fault. These motions are much larger than estimates derived from empirical relations or other numerical simulations. Standard area-magnitude relations predict that the 170 × 16 km fault used in the simulations would produce an Mw 7.5 earthquake, giving a moment of 2.0 × 1027 dyne-cm, which is 2.4 times smaller than the moment used by Olsen et al. (1995). Further, self-similar scaling predicts a rise time of 3 sec for an Mw 7.75 event and 2.2 sec for an Mw 7.5 event. The filtered impulse slip function used by Olsen et al. (1995) has an effective rise time of 1.6 sec, yielding a response that is about 2 times larger than expected for periods less than 5 sec. This combination of high seismic moment and short rise time, along with the use of a uniform slip distribution, leads to the extreme ground-motion levels predicted by Olsen et al. (1995). To quantify the sensitivity of the long-period ground-motion response to source parameterization, we have performed 3D finite-difference (FD) simulations using various combinations of seismic moment, source rise time, and slip heterogeneity. These calculations incorporate the same grid dimensions, fault size, and bandwidth employed by Olsen et al. (1995). With a moment of 2.0 ՠ1027 dyne-cm, a rise time of 2 sec, and a smoothly heterogeneous slip distribution, we simulate peak long-period ground velocities of 155 cm/sec in the near-fault region and 40 cm/sec in the Los Angeles basin. These values are much closer to (although still higher than) empirical predictions. A uniform slip distribution produces the largest peak motions, both in the near-fault region and in the Los Angeles basin, whereas a rough asperity slip distribution noticeably reduces the maximum near-fault ground velocities. Our results indicate that the accurate simulation of long-period ground motions requires a realistic source parameterization, including appropriate choices of seismic moment and rise time, as well as the use of spatial and temporal variations in slip distribution.

FAULT SLIP DISTRIBUTION ALONG THE SOUTHERN 15 KM OF THE M7.1 RIDGECREST EARTHQUAKE SURFACE RUPTURE

2020 ◽  
Author(s):  
Sinan O. Akciz ◽  
◽  
Salena Padilla ◽  
James F. Dolan ◽  
Alex E. Hatem
Keyword(s):  
Fault Slip ◽  
Slip Distribution ◽  
Surface Rupture ◽  
Fault Slip Distribution

Inferred fault geometry and slip distribution of the 2010 Jiashian, Taiwan, earthquake is consistent with a thick-skinned deformation model

2011 ◽  
Vol 301 (1-2) ◽  
pp. 78-86 ◽  
Author(s):  
Kuo-En Ching ◽  
Kaj M. Johnson ◽  
Ruey-Juin Rau ◽  
Ray Y. Chuang ◽  
Long-Chen Kuo ◽  
...  
Keyword(s):  
Slip Distribution ◽  
Deformation Model ◽  
Fault Geometry ◽  
Taiwan Earthquake
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