Joint approach combining damage and paleoseismology observations constrains the 1714 A.D. Bhutan earthquake at magnitude 8 ± 0.5. Issue 20 (27th October 2016)

• Record Type: Journal Article
• Authors: Hetényi, György; Le Roux‐Mallouf, Romain; Berthet, Théo; Cattin, Rodolphe; Cauzzi, Carlo; Phuntsho, Karma; Grolimund, Remo
• Is Part Of: Geophysical research letters. Volume 43:Issue 20(2016)
• Page Start: 10, 695
• Page End: 10, 702
• Publication Date: 2016-10-27
• Subjects: historical earthquake -- paleoseismology -- damage intensity -- Himalaya -- Bhutan -- seismic cycle; Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1002/2016GL071033
• Languages: English
• ISSNs: 0094-8276

Abstract

Abstract: The region of Bhutan is thought to be the only segment of the Himalayas not having experienced a major earthquake over the past half millennium. A proposed explanation for this apparent seismic gap is partial accommodation of the India‐Asia convergence further south across the Shillong Plateau, yet the seismic behavior of the Himalayan megathrust in Bhutan is unknown. Here we present historical documents from the region reporting on an earthquake in 1714 A.D. and geological evidence of surface rupture to constrain the latest large event in this area. We compute various earthquake scenarios using empirical scaling relationships relating magnitude with intensity, source location and rupture geometry. Our results constrain the 1714 A.D. earthquake to have ruptured the megathrust in Bhutan, most likely during a M 7.5–8.5 event. This finding reclassifies the apparent seismic gap to a former information gap and implies that the entire Himalayan arc has a high level of earthquake potential. Key Points: New historical and paleoseismological data are analyzed jointly The approach constrains the 1714 A.D. earthquake in Bhutan with a magnitude around 8 The entire Himalaya can generate megathrust earthquakes; there are no seismic gaps