Seismic moments of major earthquakes and the average rate of slip in central Asia

Chen, Wang‐Ping; Molnár, Péter

doi:10.1029/jb082i020p02945

Cited by 300 publications

(154 citation statements)

References 22 publications

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“…We therefore have chosen to retain the original body-wave magnitudes during inversion. For the largest event in the catalog, the 1950 Chayu earthquake in eastern Assam, we use the hypocentral location and magnitude listed in Chen and Molnar (1977).…”

Section: Methodsmentioning

confidence: 99%

Intensity, Magnitude, Location, and Attenuation in India for Felt Earthquakes since 1762

Szeliga¹,

Hough²,

Martin³

et al. 2010

Bulletin of the Seismological Society of America

179

132

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A comprehensive, consistently interpreted new catalog of felt intensities for India (Martin and Szeliga, 2010, this issue) includes intensities for 570 earthquakes; instrumental magnitudes and locations are available for 100 of these events. We use the intensity values for 29 of the instrumentally recorded events to develop new intensity versus attenuation relations for the Indian subcontinent and the Himalayan region. We then use these relations to determine the locations and magnitudes of 234 historical events, using the method of Bakun and Wentworth (1997). For the remaining 336 events, intensity distributions are too sparse to determine magnitude or location. We evaluate magnitude and location accuracy of newly located events by comparing the instrumental-with the intensity-derived location for 29 calibration events, for which more than 15 intensity observations are available. With few exceptions, most intensity-derived locations lie within a fault length of the instrumentally determined location. For events in which the azimuthal distribution of intensities is limited, we conclude that the formal error bounds from the regression of Bakun and Wentworth (1997) do not reflect the true uncertainties. We also find that the regression underestimates the uncertainties of the location and magnitude of the 1819 Allah Bund earthquake, for which a location has been inferred from mapped surface deformation. Comparing our inferred attenuation relations to those developed for other regions, we find that attenuation for Himalayan events is comparable to intensity attenuation in California (Bakun and Wentworth, 1997), while intensity attenuation for cratonic events is higher than intensity attenuation reported for central/eastern North America (Bakun et al., 2003). Further, we present evidence that intensities of intraplate earthquakes have a nonlinear dependence on magnitude such that attenuation relations based largely on small-to-moderate earthquakes may significantly overestimate the magnitudes of historical earthquakes.

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Section: Methodsmentioning

confidence: 99%

Intensity, Magnitude, Location, and Attenuation in India for Felt Earthquakes since 1762

Szeliga¹,

Hough²,

Martin³

et al. 2010

Bulletin of the Seismological Society of America

179

132

View full text Add to dashboard Cite

show abstract

“…There appears to have been no major (M . 7.6) earthquakes since at least 1911 along the Altyn Tagh Fault (Chen & Molnar 1977). A traverse across the Altyn Tagh Fault and Kun Lun by Molnar et al (1987a,b) revealed evidence for relatively recent faulting from 10 m offset ridges and fresh mole tracks 0.4 m high, the freshness of which they considered to point to an earthquake in the last few hundred years.…”

Section: Earthquake Historymentioning

confidence: 99%

Crustal–lithospheric structure and continental extrusion of Tibet

Searle

Elliott

Phillips

et al. 2011

JGS

237

154

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Crustal shortening and thickening to c. 70-85 km in the Tibetan Plateau occurred both before and mainly after the c. 50 Ma India-Asia collision. Potassic-ultrapotassic shoshonitic and adakitic lavas erupted across the Qiangtang (c. 50-29 Ma) and Lhasa blocks (c. 30-10 Ma) indicate a hot mantle, thick crust and eclogitic root during that period. The progressive northward underthrusting of cold, Indian mantle lithosphere since collision shut off the source in the Lhasa block at c. 10 Ma. Late Miocene-Pleistocene shoshonitic volcanic rocks in northern Tibet require hot mantle. We review the major tectonic processes proposed for Tibet including 'rigid-block', continuum and crustal flow as well as the geological history of the major strikeslip faults. We examine controversies concerning the cumulative geological offsets and the discrepancies between geological, Quaternary and geodetic slip rates. Low present-day slip rates measured from global positioning system and InSAR along the Karakoram and Altyn Tagh Faults in addition to slow long-term geological rates can only account for limited eastward extrusion of Tibet since Mid-Miocene time. We conclude that despite being prominent geomorphological features sometimes with wide mylonite zones, the faults cut earlier formed metamorphic and igneous rocks and show limited offsets. Concentrated strain at the surface is dissipated deeper into wide ductile shear zones.

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“…Kayal (figures 9 and 12 (b)). Chen and Molnar (1977), however, based on first motion data, determined a thrust faulting solution. Armijo et al (1989) preferred the strike slip solution of the 1950 earthquake interpreting the right-lateral strike-slip on the Po Qu fault zone in southeast Tibet, which wraps around the eastern syntaxis and connects with the right-lateral strike-slip Sagaing fault zone ( figure 12(b)).…”

mentioning

confidence: 99%