Crustal deformation, spatial distribution of earthquakes and along strike segmentation of the Sagaing Fault, Myanmar

Abstract

The ∼1200 km long north-south oriented Sagaing fault (plate boundary fault between the Burma and Sunda plates), entirely located in Myanmar, passes through some major cities, and has witnessed several major earthquakes since prehistoric time, including the recent Mw 6.8 Thabeikkyin earthquake in 2012. The Sagaing fault accommodates ∼50–55% of dextral motion of the India-Sunda plate motion. Combined, geodetic observations and rheological considerations using topography as a proxy, we propose along strike segmentation of the Sagaing fault from centrally locked segment to creeping segment further north along the Koma fault. Such segmentation facilitates stress transfer (or loading) from creeping segment to locked segment, and influences earthquake nucleation process and along strike spatial extent of great earthquake ruptures. Topographic margins and their relative strength, predicted from the Newtonian channel flow model, also support the along strike segmentation behaviour.