At subduction zones, slip along the shallowest parts of the plate boundary is generally thought to be aseismic. Observations of very-low-frequency earthquakes occurring at shallow levels on the plate boundary of the Nankai Trough subduction zone imply that slow but seismic slip can occur there, and could potentially generate tsunamigenic earthquakes.
- Hiroko Sugioka
- Taro Okamoto
- Yoshio Fukao
