Next big Himalayan earthquake: Doon Valley watch out

The GarhwalKumaon segment of the northwest NW Himalayas is seismically the most vulnerable section of the region with a potential to generate great earthquakes warns a new study by researchers from multiple institutions in IndiaTheir findings reported in the journal Earth and Planetary Science Letters is based on analysis of five years 20132018 of continuous GPS measurements from 28 stations located in the GarhwalKumaon Himalayas and the adjoining IndoGangetic plainsLifted by the subduction of the Indian tectonic plate under the Eurasian Plate the Himalayan mountain range runs in an arc about 2400km long separating the plains of the Indian subcontinent from the Tibetan PlateauPartly in India and partly in western Nepal the NW Himalayas have not experienced a great earthquake since at least 1505 Vineet Gahalaut director of the National Centre for Seismology in New Delhi and corresponding author of the paper told this correspondentAn analysis of GPS measurements of crustal deformation suggests strong seismic coupling underneath GarhwalKumaon region he said Strong interplate coupling means the fault below GarhwalKumaon segment is locked and capable of accumulating stress The width of the coupled region according to the report is estimated to be about 85 kmThis stronglycoupled region must have accumulated a slip of more than 7 meters since the last earthquake in 1505 which is enough to produce a great earthquake in the region the researchers claim Slip is the relative displacement of formerly adjacent points on opposite sides of a faultAccording to their report GPS measurements found the convergence rate in this part of the Himalayas is about 18 millimeters per year which has continued for more than 500 years making this slice of the geological fault one of the most earthquakevulnerable segments of the Himalayan arcThe network of GPS sites in the Garhwal Himalayas the densest anywhere along the Himalayan arc provides the most reliable estimate of spatial variations of site velocities in the Himalayas the authors sayThe derived coupling map from GPS measurements has implications for seismic hazard in the GarhwalKumaon region says the report adding that the regions of highcoupling would be the regions of high seismic energy release during future earthquakesTaking the analogy from the 2015 Gorkha earthquake and 1985 Mexico earthquake the sediment filled valleys such as the Dehradun valley in the Garhwal region are expected to be the regions of potentially more damage in future eventsThis has serious implications in terms of seismic hazards the report says as the population density is higher in the frontal Himalayas and its contiguous IndoGangetic plains thus exposing more people to high nearfield ground shakingBesides this the unconsolidated sediments in the IndoGangetic plains can cause more structural damage during earthquakes and also liquefaction wherein saturated soil behaves more like a liquid than a solid as happened in the 1934 NepalBihar earthquake says the reportBesides Gahalaut the study team included scientists from Institute of Seismological Research Gandhinagar National Geophysical Research Institute Hyderabad VCSG Uttarakhand University of Horticulture and Forestry Pauri Wadia Institute of Himalayan Geology Dehradun and GB Pant National Institute of Himalayan Environment amp Sustainable Development AlmoraChittenipattu Puthenveettil Rajendran seismologist at the Indian Institute of Science in Bengaluru says the study reiterates an earlier premise that the central Himalaya is strongly coupled and is waiting to break in a great earthquake anytime soonerThe GarhwalKumaon segment of the Himalayan arc including parts of Nepal and India never had a great earthquake during the last 600700 years Rajendran told this correspondent That means more than 20 meters of seismic slip is accumulated over these years which can be released only by one or more great earthquakes Mw gt85 in the regionThis poses a serious hazard for the Himalayan region and the heavilypopulated adjacent Gangetic alluvial plains not seriously considered by the government Rajendran notedCatch up on all the latest Crime National International and Hatke news here Also download the new midday Android and iOS apps to get latest updatesThis story has been sourced from a third party syndicated feed agencies Except for the change in the headline the story has been provided ASIS AS AVAILABLE without any verification or editing from our side Midday accepts no responsibility or liability for its dependability trustworthiness reliability and data of the text Midday managementmiddaycom reserves the sole right to alter delete or remove without notice the content in its absolute discretion for any reason whatsoever