Meijde Mark van der, Ashrafuzzaman Md, Kerle Norman, Khan Saad, Werff Harald van der
Department of Earth Systems Analysis, Faculty of Geo-Information Science and Earth Observation (ITC), University of Twente, 7500 AE Enschede, The Netherlands.
Roads and Highways Department, Government of the People's Republic of Bangladesh, Sarak Bhaban, Tejgaon, Dhaka 1208, Bangladesh.
Sensors (Basel). 2020 Jan 26;20(3):678. doi: 10.3390/s20030678.
It remains elusive why there was only weak and limited ground shaking in Kathmandu valley during the 25 April 2015 Mw 7.8 Gorkha, Nepal, earthquake. Our spectral element numerical simulations show that, during this earthquake, surface topography restricted the propagation of seismic energy into the valley. The mountains diverted the incoming seismic wave mostly to the eastern and western margins of the valley. As a result, we find de-amplification of peak ground displacement in most of the valley interior. Modeling of alternative earthquake scenarios of the same magnitude occurring at different locations shows that these will affect the Kathmandu valley much more strongly, up to 2-3 times more, than the 2015 Gorkha earthquake did. This indicates that surface topography contributed to the reduced seismic shaking for this specific earthquake and lessened the earthquake impact within the valley.
2015年4月25日发生在尼泊尔戈尔哈的Mw 7.8级地震期间，加德满都谷地为何仅有微弱且有限的地面震动，这一点仍不明朗。我们的谱元数值模拟显示，在此次地震期间，地表地形限制了地震能量向谷地的传播。山脉将传入的地震波大部分引向了谷地的东部和西部边缘。因此，我们发现谷地内部大部分地区的峰值地面位移出现了衰减。对在不同位置发生的相同震级的其他地震情景进行建模表明，这些情景对加德满都谷地的影响将比2015年戈尔哈地震强烈得多，高达2至3倍。这表明地表地形导致了此次特定地震的地震震动减弱，并减轻了谷地内的地震影响。
