Additional Report for Acoustic Signals in 1996

Acoustic Signals in 1996 from Unknown Source

western Pacific Ocean


Index of Monthly Reports

Reports are organized chronologically and indexed below by Month/Year (Publication Volume:Number), and include a one-line summary. Click on the index link or scroll down to read the reports.

01/1996 (BGVN 21:01) Acoustic signals in late January; source not locatable


Contents of Monthly Reports

All information contained in these reports is preliminary and subject to change.

01/1996 (BGVN 21:01) Acoustic signals in late January; source not locatable

The JMA Ocean Bottom Seismograph off the Boso Peninsula (E of Tokyo) detected T-phase-like signals after 22 January, and clear T-phase signals on 27 January (figure 1). According to tentative analyses of arrival times at the detectors, the signals were interpreted to have propagated from the S. As of mid-February, JMA had not determined a specific source for these signals. However, discolored seawater was observed above two submarine volcanoes in the Volcano Islands during January: Minami-Hiyoshi on 12 January, and Fukutoku-okanoba on 12, 22, and 23 January.

Figure 1. Example of T-phase signals (spikes) detected by the Ocean Bottom Seismograph off the Boso Peninsula, Japan, 27 January 1996. Courtesy of JMA.

Information Contact: Volcanological Division, Seismological and Volcanological Department, Japan Meteorological Agency (JMA), 1-3-4 Ote-machi, Chiyoda-ku, Tokyo 100 Japan.