Accurate Relative Earthquake Hypocenters Reveal Structure of the Burma Subduction Zone

Chapter 2 Active tectonics of Myanmar and the Andaman Sea

“…The majority of other seismicity recorded beneath Myanmar occurs within the subducted Indian Plate, at depths of up to 160 km (e.g. Stork et al 2008). These earthquakes form the Burma Seismic Zone, which is discussed in detail in the section 'Seismicity within the downgoing Indian plate'.…”

“…GPS velocities relative to stable India taken from Maurin et al (2010), Gahalaut et al (2013) and Vernant et al (2014) and converted to a consistent reference from Vernant et al (2014). Coloured dots indicate earthquake locations from Stork et al (2008). Black circles indicate depths <20 km, blue dots depths of 20-60 km, yellow dots depths of 60-100 km and red dots >100 km.…”

“…Earthquake focal mechanisms are shown in bold colours when obtained through body-waveform modelling (Chen & Molnar 1990;Mitra et al 2005) and faint colours when taken from the GCMT catalogue with depths constrained by Stork et al (2008) or depth-phase modelling by Copley & McKenzie (2007). The dark-grey low-angle thrust was found to lie at 5 km by both Copley & McKenzie (2007) and Stork et al (2008). Light-grey earthquakes were selected from the GCMT catalogue because their mechanisms match the shortening direction of the anticlines.…”

“…Most of the instrumentally recorded seismicity below the TFB occurs within the downgoing Indian Plate (Chen & Molnar 1990;Copley & McKenzie 2007;Stork et al 2008;Kumar et al 2015) (Figs 2.12 and 2.13). There is some evidence for earthquakes occurring within the overlying sediments.…”

“…Seismological evidence has been cited both in support of (Stork et al 2008;Hurukawa et al 2012) and against (Kundu & Gahalaut 2012;Rangin et al 2013) ongoing subduction at the present day. This debate has important implications for our understanding of the seismic hazard and tectonics of the region.…”