[H-DS09] [EE] Landslides and related phenomena

[HDS09-04] Silent Landslide -Waveform Records from a Seismometer Settled on a Moving Landslide Block-

*Issei Doi¹, Sumio Matsuura¹, Hikaru Osawa¹, Tatsuya Shibasaki², Shinichi Tosa² (1.Disaster Prevention Research Institute, 2.Japan Conservation Co. Ltd.)

We recorded seismic waveforms during landslides using a seismometer settled on a moving landslide block with the thickness about 5 m. The landslide started to move at eleven O’clock on Jun. 17, 2016, continuing to move for next 20 hours, together with the seismometer. We examined the seismograms and running spectrums, and resultantly, only ten events with short durations were found during sliding. We also calculted the background amplitude levels in the several frequency bands. They marked higher values, compared with those in sunny days. However, such high amplitudes were experienced several times in the cases of past heavy rains and storms. Therefore, these high background amplitude levels derived from ambient noises due to rain, winds, and oceanic waves. We could conclude that the landslide generated very small seismic energies, at least below the ambient noise level.