Pulsed strain release on the Altyn Tagh fault, northwest China

Earth and Planetary Science Letters
By: , and 

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Abstract

Earthquake recurrence models assume that major surface-rupturing earthquakes are followed by periods of reduced rupture probability as stress rebuilds. Although purely periodic, time- or slip-predictable rupture models are known to be oversimplifications, a paucity of long records of fault slip clouds understanding of fault behavior and earthquake recurrence over multiple ruptures. Here, we report a 16 kyr history of fault slip—including a pulse of accelerated slip from 6.4 to 6.0 ka—determined using a Monte Carlo analysis of well-dated offset landforms along the central Altyn Tagh strike-slip fault (ATF) in northwest China. This pulse punctuates a median rate of 8.1+1.2/−0.9 mm/a and likely resulted from either a flurry of temporally clustered ∼Mw 7.5 ground-rupturing earthquakes or a single large >Mw 8.2 earthquake. The clustered earthquake scenario implies rapid re-rupture of a fault reach >195 km long and indicates decoupled rates of elastic strain energy accumulation versus dissipation, conceptualized as a crustal stress battery. If the pulse reflects a single event, slip-magnitude scaling implies that it ruptured much of the ATF with slip similar to, or exceeding, the largest documented historical ruptures. Both scenarios indicate fault rupture behavior that deviates from classic time- or slip-predictable models.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Pulsed strain release on the Altyn Tagh fault, northwest China
Series title Earth and Planetary Science Letters
DOI 10.1016/j.epsl.2016.11.024
Volume 459
Year Published 2017
Language English
Publisher Elsevier
Contributing office(s) Geologic Hazards Science Center
Description 10 p.
First page 291
Last page 300
Country China
Other Geospatial Altyn Tagh fault