Archive for March, 2011

2 Magnitude 6.6 Aftershocks – OFF THE EAST COAST OF HONSHU, JAPAN – March 22, 2011

March 22, 2011

The BC-ESP recorded two magnitude 6.6 aftershocks off the east coast of Honshu, Japan on March 22, 2011.
LATITUDE  37.249°N,  LONGITUDE  143.956°E
For more info on these earthquakes, go to US Geological Survey report.
Below is a seismogram recorded on Amesbury Middle School’s seismograph.

Aftershocks of the Honshu, Japan Earthquake – March 13, 2011

March 14, 2011

The BC-ESP recorded many aftershocks of the March 11th Japan earthquake.
For a list of aftershocks with magnitudes 5.0 and larger visit the US Geological Survey report.

The east coast of Honshu, Japan will continue to feel earthquakes for quite some time.
Over 80 aftershocks have occurred with magnitudes over 5.0 in the past few days alone.

The U.S.G.S. defines aftershocks to be, “earthquakes that follow the largest shock of an earthquake sequence. They are smaller than the mainshock and within 1-2 rupture lengths distance from the mainshock. Aftershocks can continue over a period of weeks, months, or years. In general, the larger the mainshock, the larger and more numerous the aftershocks, and the longer they will continue.”

Reflections on the Powerful Earthquake in Japan

Living on an Active Planet


Magnitude 9.0 – NEAR THE EAST COAST OF HONSHU, JAPAN – March 11, 2011

March 11, 2011

The BC-ESP recorded the devastating magnitude 9.0 earthquake near the East coast of Honshu, Japan on March 11, 2011.  This is the largest recorded earthquake in Japan and the 5th largest earthquake recorded in the World.
Fires broke out at oil refineries, firefighters continue to battle a large fire at Cosmo Oil Co.’s refinery, 40 kilometers east of Tokyo.  Millions of homes are without electricity as utilities shut 11 nuclear power reactors.
For News:  CNN, Bloomberg, WBGH

LATITUDE  38.322°N,  LONGITUDE  142.369°E
For more info on this earthquake, go to US Geological Survey report.
For a tectonic summary, go to USGS Tectonic Summary.

A power point on the tectonics and details of this devastating earthquake and tsunami can be downloaded from the IRIS website here.
To download a PDF of this IRIS presentation, click here.

A tsunami was generated by this enormous quake and traveled miles inland Japan sending a massive body of water filled with debris that included cars, boats and houses.
The western Aleutian Islands, Alaska, were hit at 4 a.m. EST by a 5.1 foot wave.  Shemya, Alaska was reporting no damage despite the sizeable wave. By the time it reached the commercial fishing town of Dutch Harbor, the wave was just 1.6 feet.
For more tsunami info visit the Pacific Tsunami Warning Center.
For an animation of how the D.A.R.T. II deep ocean system works in assessing and reporting a tsunami, click here.