Indian Earthquakes@@@The Kangra Earthquake of 4th April, 1905

Insight into major active faults in Central Myanmar and the related geodynamic sources

\n Earthquake observations contributed by human observers provide an invaluable source of information to investigate both historical and modern earthquakes. Commonly, the observers whose eyewitness accounts are available to scientists are a self-selected minority of those who experience a given earthquake. As such these may not be representative of the overall population that experienced shaking from the event. Eyewitness accounts can contribute to modern science only if they are recorded in the first place and archived in an accessible repository. In this study, we explore the extent to which geopolitics and socioeconomic disparities can limit the number of earthquake observers whose observations can contribute to science. We first revisit a late nineteenth-century earthquake in the central United States in 1882 that provides an illustrative example of an event that has been poorly characterized due to a reliance on English-language archival materials. For modern earthquakes, we analyze data collected for recent earthquakes in California and India via the online “Did You Feel It?” (DYFI) system. In California, online data-collection systems appear to be effective in gathering eyewitness accounts from a broad range of socioeconomic groups. In India, however, responses to the DYFI system reveal a strong bias toward responses from urban areas as opposed to rural settlements, as well a bias with literacy rate. The dissimilarity of our results from modern earthquakes in the United States and India provides a caution that, in some parts of the world, contributed felt reports can still potentially provide an unrepresentative view of earthquake effects, especially if online data collection systems are not designed to be broadly accessible. This limitation can in turn potentially shape our understanding of an earthquake’s impact and the characterization of seismic hazard.

Which Earthquake Accounts Matter

\n Seismic hazard in the southern Malay Peninsula located within the Sundaland block in Southeast Asia is poorly understood. The paucity of historical earthquakes and low-magnitude instrumented seismicity has led to the assumption that this region is largely aseismic. We question this point of view by reassessing historical seismicity in this region and, in particular, a pair of moderate earthquakes in the 1920s. The first of these struck on 31 January 1922 at ≈9:10  a.m. local time (LT) for which we estimate an intensity magnitude (MI) ≈5.4, and for the second earthquake on 7 February 1922 at ≈12:15  p.m. LT, we estimate MI≈5.0. We also identify at least 34 felt earthquakes between 1803 and 1950 that were potentially local within the Sundaland block. These include a very widely felt shock (or set of shocks) on 26 June 1874 that was felt in parts of Borneo, Java, and Sumatra. The discovery of these earthquakes challenges the tectonic stability of the Malay Peninsula and the stable interior of the Sundaland block. The record of historical seismicity in this region relies heavily on European sources, and we recommend locating and consulting indigenous sources to improve the current understanding of regional seismic hazard. We also underscore the need to evaluate the impact of ground motions from rare local earthquakes on the extant building stock and on transportation infrastructure that are otherwise relatively immune to the long-period effects of distant earthquakes commonly felt in the Malay Peninsula.

The 1922 Peninsula Malaysia Earthquakes: Rare Intraplate Seismicity within the Sundaland Block in Southeast Asia

Investigating earthquake triggering of fluid seepage systems by dynamic and static stresses

https://dr.ntu.edu.sg/bitstream/10356/105369/1/A%20comprehensive%20assessment%20of%20ground%20motions%20from%20two%202016%20intra-slab%20earthquakes%20in%20Myanmar.pdf

Tay Zar Kyaw

Papers

A comprehensive assessment of ground motions from two 2016 intra-slab earthquakes in Myanmar