Tsunami Observation Instruments Were Unable to Measure Waves at Ishikawa Pref.

Courtesy of Geospatial Information Authority of Japan
The tsunami observation point in Suzu, Ishikawa Prefecture, where the seafloor was exposed due to ground uplift, on Jan. 2

Tsunami observation systems installed in the city of Suzu, Ishikawa Prefecture, were unable to detect tsunamis because the seafloor was exposed from ground uplift, the Japan Meteorological Agency said Friday.

The agency had two different kinds of observation instruments at a fishing port in the town of Nagahashi in the city, but has not received any data from them since the Jan. 1 earthquake.

Photos of the site taken by the Geospatial Information Authority of Japan showed that the seafloor within the port was exposed, making it impossible for instruments to measure the height of the sea surface and detect any tsunamis. According to the agency, this is apparently due to land uplift caused by the earthquake.

This does not affect tsunami warnings and advisories as they are are issued based on data from seismometers, the agency said, hastening to find an alternative observation point to resume tsunami detection in the area.

Courtesy of Geospatial Information Authority of Japan
The same tsunami observation point before the earthquake. The photo was taken in the spring of 2010.