Present-day crustal deformation around Sagaing fault, Myanmar

[1] Global Positioning System (GPS) measurement campaigns in Myanmar, conducted in 1998 and 2000, allow quantifying the present-day crustal deformation around the Sagaing fault system in central Myanmar. Both a regional network installed at four points within the country and a local 18-station network centered on the city of Mandalay across the Sagaing fault demonstrate that active deformation related to the northward motion of India is distributed across Myanmar in a platelet that extends from the western edge of the Shan Plateau in the east to the Andaman Trench in the west. In this platelet, deformation is rather diffuse and distributed over distinct fault systems. In the east, the Sagaing/Shan Scarp fault system absorbs < 20 mm/yr of the 35 mm/yr India/Sundaland strike-slip motion. Along this major plate boundary, strain is partitioned along the N-S trending Sagaing fault and the transtensile N160 degrees E trending Shan Scarp fault. Shortening and wrenching within the inverted central Myanmar basins, strike-slip faults affecting the Arakan Yoma fold-and-thrust belt, and oblique subduction along the Andaman trench should absorb the remaining India/Sundaland motion (> 10 mm/yr). This GPS study combined with an on land geotectonic survey demonstrate that oblique slip of India along the rigid Sundaland block is accommodated by a partitioned system characterized by distribution of deformation over a wide zone.