Earthquake Hazard and Seismology
A dense seismic network for the Kathmandu Valley
The Kathmandu Valley — home to more than two million people — sits on soft lake sediments that amplify earthquake shaking catastrophically, as the 2015 Gorkha earthquake showed. Yet the valley has fewer than five continuously operating seismic stations, and its subsurface structure is poorly constrained. HICS is designing a dense, low-cost MEMS seismometer network to produce the first detailed picture of how the ground actually moves here.
Soft sediment amplification
Seismic waves slow down and grow in amplitude as they pass from stiff bedrock into soft valley sediments — a first-order estimate of the amplification is the square root of the impedance contrast between the two:
The Kathmandu basin's thick, slow sediments give a large impedance contrast — which is precisely why shaking is so destructive, and why a dense network that maps the variation across the valley matters.
Continuous seismic stations for comparable urban areas.
Amber: existing stations. Green: HICS KTM-001. Blue: proposed MEMS nodes.
Nodes are built around the ADXL355 MEMS accelerometer with GPS timing, Raspberry Shake–compatible so the data joins the global network. See the MEMS seismometer in the instruments section.
Planned. The network design and node prototype come first; deployment follows. The goal is the first dense, openly published seismic dataset for the Kathmandu Valley.