News Details

Tsunami sensed as it approached BC

Mar 11, 2011

At 05:46UTC (2:46PM local time), an extremely powerful earthquake centred in the ocean near the northeast coast of Japan's Honshu Island generated a deadly tsunami that inundated coastal areas, inflicting widespread devastation and claiming many lives. 

Real-time data from NEPTUNE Canada undersea cabled ocean network, owned and operated by the University of Victoria in British Columbia, helped scientists determine the timing and size of the tsunami as it reached Canada’s West Coast earlier today.

Pressure sensor locations
Locations of pressure sensors that detected the Japan tsunami. (Click to enlarge.)

The NEPTUNE Canada network registered the tsunami at its pressure sensors across the Juan de Fuca tectonic plate. It first appeared at the sensor 220 km offshore at 6:35 a.m. PST as a 15-cm wave. Less than 10 minutes later, a sensor about 120 km offshore recorded the wave as it passed overhead. The wave arrived at a sensor near the coast between Ucluelet and Bamfield as a 40-cm wave about 40 minutes later. The following plots show the pressure data as viewed in the NEPTUNE Canada Plotting Utility.

Tsunami plots
Plots of tsunami waves as captured by our bottom pressure recorders. (Click to enlarge.)

The following set of plots shows the same tsunami signature, but after removing ocean tides from the data:

Tsunami plots without tides
Plots of tsunami waves after removing ocean tides from the data. (Click to enlarge.)

NEPTUNE Canada sends its data to the Department of Fisheries and Oceans (DFO), which is responsible for handling tsunami response in Canada. The tremors and waves that register on NEPTUNE Canada also go to IRIS, the global network of earthquake information.

Raw seismic data of the earthquake from two of NEPTUNE Canada's ocean bottom seismometers. (Click to enlarge.)

NEPTUNE Canada scientists will continue to monitor its instruments, as more aftershocks are expected. Any tremors greater than 7.0 may send more tsunamis across the Pacific Ocean.

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