Earthquakes in the Himalaya: How Large? How Often? How Destructive?

Major large earthquakes are known to have occurred in the Himalaya, including the Mw~8.7 Assam earthquake of 1950, the largest continental earthquake ever documented. However, large stretches of the Himalayan arc haven't produced any significant earthquakes over the historical period. We would like to know whether future destructive earthquakes in the Himalaya would fill these gaps, repeat the known past historical ruptures or actually bear no relation to past large earthquakes. These scenario have indeed quite different implications for seismic hazard. This issue cannot be answered only based on historical and paleoseismological data as these records are too incomplete or uncertain. Further insight might be gained by combining these data with geodetic observations of interseismic strain and geological observation of fault slip rate. I'll show that a simple strain budget rationale imply that millenary Mw>8.5 earthquakes are likely, and that, based on observations from the 2015 Mw 7.8 Gorkha earthquake in Nepal, some aspects of future Himalayan earthquakes might be anticipated. I will however point to caveats and limitations of this approach and discuss how it might be improved in the future using physics-based numerical simulations of the earthquake cycle.