Geologic Inheritance and Earthquake Rupture Processes: The 1905 M ≥ 8 Tsetserleg‐Bulnay Strike‐Slip Earthquake Sequence, Mongolia

Abstract

In 1905, 14 days apart, two M ~ 8 continental strike‐slip earthquakes, the Tsetserleg and Bulnay earthquakes, occurred on the Bulnay fault system, in Mongolia. Together, they ruptured four individual faults, with a total length of ~676 km. Using submetric optical satellite images “Pleiades” with ground resolution of 0.5 m, complemented by field observation, we mapped in detail the entire surface rupture associated with this earthquake sequence. Surface rupture along the main Bulnay fault is ~388 km in length, striking nearly E‐W. The rupture is formed by a series of fault segments that are 29 km long on average, separated by geometric discontinuities. Although there is a difference of about 2 m in the average slip between the western and eastern parts of the Bulnay rupture, along‐fault slip variations are overall limited, resulting in a smooth slip distribution, except for local slip deficit at segment boundaries. We show that damage, including short branches and secondary faulting, associated with the rupture propagation, occurred significantly more often along the western part of the Bulnay rupture, while the eastern part of the rupture appears more localized and thus possibly structurally simpler. Eventually, the difference of slip between the western and eastern parts of the rupture is attributed to this difference of rupture localization, associated at first order with a lateral change in the local geology. Damage associated to rupture branching appears to be located asymmetrically along the extensional side of the strike‐slip rupture and shows a strong dependence on structural geologic inheritance.

The 2016 M7 Kumamoto, Japan, Earthquake Slip Field Derived From a Joint Inversion of Differential Lidar Topography, Optical Correlation, and InSAR Surface Displacements

“…Approximately half of the total shallow deformation The cyan and pink clouds show the 1-σ slip range for the lidar-optical-InSAR and optical-InSAR slip inversions, respectively. The 1905 Tsetserleg-Bulnay (Choi et al, 2018), 1999Izmit (Rockwell et al, 2002, and 2013 Balochistan (Vallage et al, 2015) earthquakes produced similar off-fault deformation. Dots show modeled slip along subfaults, and the lines contour the fault slip.…”

Rate of Slip From Multiple Quaternary Dating Methods and Paleoseismic Investigations Along the Talas‐Fergana Fault: Tectonic Implications for the Tien Shan Range

“…In central Asia, large earthquakes (M > 7.5) involving strike-slip faults have generated surface ruptures of several hundred kilometers length with coseismic offsets of several meters (Choi et al, 2018;Klinger et al, 2011;Molnar & Dayem, 2010;Rizza et al, 2011Rizza et al, , 2015Tapponnier & Molnar, 1979). For example, the 2001 M w~7 .8 Koxokili earthquake ruptured the Kunlun fault with coseismic offsets of several meters (Haibing et al, 2005;Klinger et al, 2005;Klinger et al, 2006;van der Woerd et al, 2002).…”

“…For example, the 2001 M w~7 .8 Koxokili earthquake ruptured the Kunlun fault with coseismic offsets of several meters (Haibing et al, 2005;Klinger et al, 2005;Klinger et al, 2006;van der Woerd et al, 2002). The largest continental strike-slip surface rupture ever documented is the Bulnay fault system on which two large earthquakes in 1905 ruptured an~670-km length of the fault, with coseismic offsets up to 10 m (Choi et al, 2018;Rizza et al, 2015).…”

Offset Channels May Not Accurately Record Strike‐Slip Fault Displacement: Evidence From Landscape Evolution Models

“…The relative importance of tectonic and geomorphic processes in creating observed lateral offsets is actively debated (e.g., Salisbury et al, 2018;Zielke, 2018), and understanding the evolution of offset channels postearthquake is poor compared with normal fault scarps, for which the process of postearthquake erosion and deposition is established (e.g., Burbank & Anderson, 2012). Furthermore, the recent explosion of submeter resolution satellite imagery, lidar, and topographic data sets derived from photogrammetry has created a proliferation of offset marker measurements for recent and historical earthquakes (e.g., Choi et al, 2012Choi et al, , 2018Fletcher et al, 2014; R. D. Gold et al, 2015;Klinger et al, 2005; Creek illustrating single-event (5 m) and multiple-event (≥10 m) offset channels in blue and the natural variability in channel size and spacing. (b) Map view of initial topography prior to faulting for landscape evolution models in this study.…”