In this project we aim to determine whether the Himalayan arc is “winding up, or winding down” toward (or away from) a Great Earthquake. The evidence suggests that long term crustal motion accentuated the curvature of the Himalayan arc, while present-day motion is ”undoing” that overall pattern. This could be significant because, if it is the case, then short-term motion is far more rapidly “winding up” the Himalaya towards a major energy release than would otherwise be the case. In order to fully understand the likely magnitude of the earthquake hazard we need quantify the magnitude of the rate of stress build-up. To do this we must quantify the short-term strain accumulation in the context of the longer-term contraction of the arc. A detailed study of the region in question is required, so that we can resolve this outstanding issue and identify the regions at greatest risk.
This project will accurately quantity the present day crustal deformation of the Himalayan arc with greater spatial resolution than has been done to date, with the intent that: a) we identify geophysical signals that reveal the seismic potential of the region; and b) we provide those data and information in a way that informs policy and response. Using a modeling approach similar to that described by Loveless and Meade, 2011, we will use geodetic observations to infer which are the geologic structures within the Himalaya that are accommodating the northwards motion of India. Specifically we seek to reveal what fraction of this convergent motion is being stored as elastic strain energy on the major faults of the Himalaya that may be released in the next Megathrust event. Using this approach, Loveless and Meade, 2011 were able to precisely map the highly locked and most seismically potent segment of the Japan Trough, which subsequently failed on the 11th of March 2011, causing the M9.1 Tohoku earthquake and associated tsunami.