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

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

*土井 一生¹、松浦 純生¹、大澤 光¹、柴崎 達也²、土佐 信一² (1.京都大学防災研究所、2.国土防災技術株式会社)

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.