Large paleoearthquake timing and displacement near Damak in eastern Nepal on the Himalayan Frontal Thrust

Deepak Chamlagain, Steven G. Wesnousky, Yasuhiro Kumahara, Ian Pierce, Tabor J. Reedy, Stephen J. Angster, & Bibek Giri

Submitted August 15, 2017, SCEC Contribution #7767, 2017 SCEC Annual Meeting Poster #134

An excavation across the Himalayan Frontal Thrust near Damak in eastern Nepal shows displacement on a fault plane dipping ~22° has produced vertical separation across a scarp equal to 5.5 m. Stratigraphic, structural, geometrical, and radiocarbon observations are interpreted to indicate the displacement is the result of a single earthquake of 11.3 ± 3.5 m of dip-slip displacement that occurred 1146 – 1256 AD. Empirical scaling laws indicate that thrust earthquakes characterized by average displacements of this size may produce rupture lengths of 450 - > 800 km and moment-magnitudes Mw of 8.6 to > 9. Sufficient strain has accumulated along this portion of the Himalayan arc during the roughly 800 years since the 1146 – 1256 AD earthquake to produce another earthquake displacement of similar size.

Key Words
Himalaya, Earthquakes, Paleoseismology, Tectonics, Seismic Hazard

Citation
Chamlagain, D., Wesnousky, S. G., Kumahara, Y., Pierce, I., Reedy, T. J., Angster, S. J., & Giri, B. (2017, 08). Large paleoearthquake timing and displacement near Damak in eastern Nepal on the Himalayan Frontal Thrust. Poster Presentation at 2017 SCEC Annual Meeting.


Related Projects & Working Groups
Earthquake Geology