Insights into earthquake source physics from high-frequency ... - IRIS

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Zaliapin and Ben-Zion (2009) Zone 5: The “negative” asymmetry is consistent with evidence [e.g., Fuis et al., 2001] for “reversed” velocity contrast along the Mojave section of the SAF (with the NE block having faster velocities) and observed asymmetric rock damage in that section [Dor et al., 2006a,b] Zones 11, 12: The “negative” asymmetry along the San Jacinto Zone fault 1: The (zone11) lack of is significant consistent asymmetry with Zones seismic 48, is 51: imaging The “positive” of the velocity asymmetry is consistent with seismic imaging consistent Catalogs from Powers (2009) contrast with there lack [Scott of et pronounced al., 1994] of the and velocity asymmetric contrast rock along damage the Parkfield section of the SAF [e.g., Thurber contrast based across on trapped the eastern waves Garlock [Lewis et al., fault. et al., 2006; 2005] Ben-Zion and geological et al., 1992]. Clustering The results in and zone symmetry 48 to the left analyses are for zone 51 signals [Dor et al., 2006a; Wechsler consistent et al., 2009]. with Similar similar findings of Rubin and Gillard [2000]. asymmetry is seen for the Ellsinore fault (zone 12) Asymmetry results for different fault zones
Conclusions II • Ruptures along a bimaterial interface evolve for ranges of realistic conditions to narrow pulses with preferred propagation direction, high slip velocity, and possible transient fault opening near the rupture tip. • Such properties can have fundamental implications to many basic (earthquake physics) and practical (shaking hazard estimates) aspects of earthquake seismology. • The cumulative effect of such ruptures is expected to produce asymmetric damage pattern across the fault in the top few km. • Multi-scale multi-signal geological mapping show strongly asymmetric damage in the structures of the San Jacinto, Punchbowl, San Andreas and North Anatolian faults, which correlate with available information on the velocity structures at depth as predicted for ruptures on a bimaterial interface. • Analyses of trapped waves in the San Jacinto fault near Anza and head waves in the San Andreas fault near Hollister show asymmetric damage zone in the ~3.5 km, with more damage on the predicted sides of the faults. • Analyses of dynamic triggering patterns along several sections of the SAF and SJF indicate clear asymmetries, compatible with statistically-preferred propagation directions as predicted by for the local velocity models. • More direct tests requires high-resolution high-frequency seismology!!!
Page 1 and 2: Insights into earthquake source phy
Page 3 and 4: Basic relations Total strain has el
Page 5 and 6: Order of magnitude estimates of con
Page 7 and 8: Conclusions I • The ratio of radi
Page 9 and 10: Can be relevant to numerous importa
Page 11 and 12: Wrinkle-like rupture pulse complian
Page 13 and 14: Estimates of slip velocities (Ben-Z
Page 15 and 16: Slip-weakening friction (Shi and Be
Page 17 and 18: Simulations with imposed super-shea
Page 19 and 20: The results are robust with respect
Page 21 and 22: Relations to field observations? Ne
Page 23 and 24: Damage generation for different dep
Page 25 and 26: com. fracture length (cm) 60 50 40
Page 27 and 28: Scott et al. (1994) Shapiro et al.
Page 29 and 30: Pulverized rocks in the Mojave sect
Page 31: Asymmetric dynamic earthquake trigg

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