Stacey S. Martin V. Gahalaut A. Joshi M. Landes R. Bossu Susan E. Hough 2016 <p><span>We use 21 strong motion recordings from Nepal and India for the 25 April 2015 moment magnitude (M</span>_W<span>) 7.8 Gorkha, Nepal, earthquake together with the extensive macroseismic intensity data set presented by Martin et al. (Seism Res Lett 87:957–962, </span><span class="CitationRef"><a title="View reference" href="https://link.springer.com/article/10.1007%2Fs11069-016-2505-8#CR41" data-mce-href="https://link.springer.com/article/10.1007%2Fs11069-016-2505-8#CR41">2015</a></span><span>) to analyse the distribution of ground motions at near-field and regional distances. We show that the data are consistent with the instrumental peak ground acceleration (PGA) versus macroseismic intensity relationship developed by Worden et al. (Bull Seism Soc Am 102:204–221, </span><span class="CitationRef"><a title="View reference" href="https://link.springer.com/article/10.1007%2Fs11069-016-2505-8#CR69" data-mce-href="https://link.springer.com/article/10.1007%2Fs11069-016-2505-8#CR69">2012</a></span><span>), and use this relationship to estimate peak ground acceleration from intensities (PGA</span>_EMS<span>). For nearest-fault distances (R</span>_RUP<span>&nbsp;&lt;&nbsp;200&nbsp;km), PGA</span>_EMS<span> is consistent with the Atkinson and Boore (Bull Seism Soc Am 93:1703–1729, </span><span class="CitationRef"><a title="View reference" href="https://link.springer.com/article/10.1007%2Fs11069-016-2505-8#CR5" data-mce-href="https://link.springer.com/article/10.1007%2Fs11069-016-2505-8#CR5">2003</a></span><span>) subduction zone ground motion prediction equation (GMPE). At greater distances (R</span>_RUP<span>&nbsp;&gt;&nbsp;200&nbsp;km), instrumental PGA values are consistent with this GMPE, while PGA</span>_EMS<span> is systematically higher. We suggest the latter reflects a duration effect whereby effects of weak shaking are enhanced by long-duration and/or long-period ground motions from a large event at regional distances. We use PGA</span>_EMS<span> values within 200&nbsp;km to investigate the variability of high-frequency ground motions using the Atkinson and Boore (Bull Seism Soc Am 93:1703–1729, </span><span class="CitationRef"><a title="View reference" href="https://link.springer.com/article/10.1007%2Fs11069-016-2505-8#CR5" data-mce-href="https://link.springer.com/article/10.1007%2Fs11069-016-2505-8#CR5">2003</a></span><span>) GMPE as a baseline. Across the near-field region, PGA</span>_EMS<span> is higher by a factor of 2.0–2.5 towards the northern, down-dip edge of the rupture compared to the near-field region nearer to the southern, up-dip edge of the rupture. Inferred deamplification in the deepest part of the Kathmandu valley supports the conclusion that former lake-bed sediments experienced a pervasive nonlinear response during the mainshock (Dixit et al. in Seismol Res Lett 86(6):1533–1539, </span><span class="CitationRef"><a title="View reference" href="https://link.springer.com/article/10.1007%2Fs11069-016-2505-8#CR19" data-mce-href="https://link.springer.com/article/10.1007%2Fs11069-016-2505-8#CR19">2015</a></span><span>; Rajaure et al. in Tectonophysics, </span><span class="CitationRef"><a title="View reference" href="https://link.springer.com/article/10.1007%2Fs11069-016-2505-8#CR57" data-mce-href="https://link.springer.com/article/10.1007%2Fs11069-016-2505-8#CR57">2016</a></span><span>. Ground motions were significantly amplified in the southern Gangetic basin, but were relatively low in the northern basin. The overall distribution of ground motions and damage during the Gorkha earthquake thus reflects a combination of complex source, path, and site effects. We also present a macroseismic intensity data set and analysis of ground motions for the M</span>_W<span>7.3 Dolakha aftershock on 12 May 2015, which we compare to the Gorkha mainshock and conclude was likely a high stress-drop event.</span></p> application/pdf 10.1007/s11069-016-2505-8 en International Society for the Prevention and Mitigation of Natural Hazards A comparison of observed and predicted ground motions from the 2015 M_W7.8 Gorkha, Nepal, earthquake article