Slip deficit in central Nepal: omen for a repeat of the 1344 AD earthquake?

Abstract

In 1255, 1344, and 1408 AD, then again in 1833, 1934, and 2015, large earthquakes, devastated Kathmandu. The 1255 and 1934 surface ruptures have been identified east of the city, along comparable segments of the Main Frontal Thrust (MFT). Whether the other two pairs of events were similar is unclear. Taking into account charcoal's age inheritance, we revisit the timing of terrace offsets at key sites to compare them with the seismic record since 1200 AD. The location, extent, and moment of the 1833 and 2015 events imply that they released only a small part of the regional slip deficit on a deep thrust segment that stopped north of the Siwaliks. By contrast, the 1344 or 1408 AD earthquake may have ruptured the MFT up to the surface in central Nepal between Kathmandu and Pokhara, east of the surface trace of the great 1505 AD earthquake which affected western Nepal. If so, the whole megathrust system in Nepal broke in a sequence of earthquakes that lasted less than three centuries, with ruptures that propagated up to the surface from east to west. Today's situation in the Himalayan seismic sequence might be close to that of the fourteenth century.

A comparison of observed and predicted ground motions from the 2015 MW7.8 Gorkha, Nepal, earthquake

“…Bilham 1999;Ambraseys and Douglas 2004;Martin and Szeliga 2010;Szeliga et al 2010). A growing number of completed and ongoing palaeoseismic studies in the Nepal Himalayas (Lavé et al 2005;Mugnier et al 2005;Sapkota et al 2013;Bollinger et al 2014;Murphy et al 2014;Karakaş et al 2015;Bollinger et al 2016;Hossler et al 2016) have contributed further to our knowledge of pre-instrumental earthquakes in the region, although the catalogue clearly remains far from complete. It is clear that Himalayan earthquakes pose a significant hazard to not only Nepal and the Kathmandu valley specifically, but also the densely populated and rapidly urbanizing Gangetic Basin (e.g.…”

Unearthed lessons of 25 April 2015 Gorkha earthquake (MW 7.8): geotechnical earthquake engineering perspectives

“…Gorkha earthquake is no exception in terms of enormous losses in environmental impacts, casualties and infrastructures. Details on geology and seismo-tectonics of Nepal Himalaya can be found in several literatures by Upreti and Le Fort (1999), Sakai (2001), Pandey et al (1999), Dhital (2014), Hossler et al (2016); Bollinger et al (2016), Wesnousky et al (2017) and others.…”

Overestimation of the earthquake hazard along the Himalaya: constraints in bracketing of medieval earthquakes from paleoseismic studies

“…The surface rupture of 1255 AD earthquake reported from the Sir trenches in Central Nepal (Sapkota et al 2013) has been extended up to far east to Harmutty in the eastern part India (Mishra et al 2016) or at least to Hokse in eastern Nepal by Bollinger et al (2016). The 1255 AD is assigned to be a giant earthquake rupturing ~800 km of the Himalayan arc (Mishra et al 2016).…”

“…In the last few decades, several paleo-seismological investigation has been carried out along the active HFT which has provided significant data to understand the occurrence of large magnitude earthquakes in the Himalayan region (Wesnousky et al 1999;Malik and Nakata 2003;Lavé et al 2005;Malik et al 2008Malik et al , 2010aMalik et al , b, 2015Malik et al , 2016Kumar and Mahajan 2001;Kumar et al 2006Kumar et al , 2010Kumahara and Jayangondaperumal 2013;Sapkota et al 2013;Yule et al 2006;Bollinger et al 2014Bollinger et al , 2016Jayangondaperumal et al 2016;Mishra et al 2016). However, there exist constraints in terms of their period of occurrence and in determining the extent of surface rupture.…”