Aseismic plate boundary in the Indo-Burmese wedge, northwest Sunda Arc

作者：Gahalaut Vineet K^*; Kundu Bhaskar; Laishram Sunil Singh; Catherine Joshi; Kumar Arun; Singh M Devchandra; Tiwari R P; Chadha R K; Samanta S K; Ambikapathy A; Mahesh P; Bansal Amit; Narsaiah M

来源：Geology, 2013, 41(2): 235-238.

DOI：10.1130/G33771.1

Plate motion, crustal deformation, and earthquake occurrence processes in the northwest Sunda Arc, which includes the Indo-Burmese wedge (IBW) in the forearc and the Sagaing fault in the backarc, are very poorly constrained. Plate reconstruction models and geological structures in the region suggest that subduction in the IBW occurred in the geological past, but whether it is still active and how the plate motion between the India and Sunda plates is partitioned between motion in the IBW and Sagaing fault is largely unknown. Recent G PS measurements of crustal deformation and available long-term rates of motion across the Sagaing fault suggest that similar to 20 +/- 3 mm/yr of the relative plate motion of similar to 36 mm/yr between the India and Sunda plates is accommodated at the Sagaing fault through dextral strike-slip motion. We report results from a dense GPS network in the IBW that has operated since 2004. Our analysis of these measurements and the seismicity of the IBW suggest that the steeply dipping Churachandpur-Mao fault in the IBW accommodates the remaining motion of similar to 18 +/- 2 mm/yr between the India and Sunda plates through dextral strike-slip motion, and this motion occurs predominantly through velocity strengthening frictional behavior, i.e., aseismic slip. The aseismic motion on this plate boundary fault significantly lowers the seismic hazard due to major and great interplate earthquakes along this plate boundary.

• 出版日期2013-2