Earthquake Accompanied by Mudflow Observed by a Cabled Observatory off Hatsushima Island in Sagami Bay in April 2006

Abstract

Mudflow associated with an earthquake of magnitude 5.5 was detected with a cabled observatory on deep seafloor off Hatsushima Island in Sagami Bay in April 2006. Environmental fluctuations associated with the mudflow were observed. Water current 12m above the seafloor observed by ADCP was 27 cm/s at maximum and several millimeter sedimentation was recognized by video images. The fluctuation of electric potential difference between submarine cable ends indicates motional induction caused by the mudflow on the slope west of the observatory.