Breaking News: Magnitude 8.9 Earthquake Outside of Japan

Magnitude 8.9 earthquake hit Japan; the most powerful earthquake for Japan in at least 100 years, Friday at 5:46:23 UTC (which was 2:46:23 P.M. local time at the epicenter). The distance of the epicenter is:
80 miles East of Sendai, Honshu, Japan (one of the hardest hit cities from the the tsunami)
110 miles East of Yamogata, Honshu, Japan
231 miles NE of Tokyo Japan

This massive quake was a result of thrust faulting near the subduction zone interface plate boundary between the Pacific and North America plates.

Subduction Zone of Pacific and North America Tectonic Plates

According to the U.S. Geologic Survey (USGS), the Pacific plate moves westward (subducts) with respect to the North American plate at a velocity of 88mm per year. Granted this number seems insignificant, but when pressure builds between the plates from the movement a significant earthquake can release, much like what happened in Japan Friday.  The Pacific plate thrusts under Japan along the Japan Trench. The earthquake that was unleashed as trust faulting occurred along the subduction plate boundary.

Pacific Ring of Fire

Now, referring to the image above, the subduction zone is a process of one plate pushing downward beneath another plate into the underlying mantle when the plates move toward each other. The plate that is denser will slide under the thicker less dense plate. 

The earthquake is one issue, the next is the tsunami that followed. Below is a video of a whirlpool that was formed from the earthquake. Absolutely fascinating.

The video and images from this event is breathtakingly heart wrenching and absolutely astonishing. Writing about it will not do any justice. Watching The Today Show Friday morning, I could not help but be speechless to the events that were unavailing on the other side of the globe.



The breakdown of a tsunami is as follows:
A tsunami is a series of water waves caused by a displacement of a large volume of water. Just a note, tsunami is a Japanese word meaning 'harbor' or 'wave.' In the case of Friday, the water above the earthquake area was displaced from its equilibrium position. As prior mentioned, this was a thrust fault earthquake. The abrupt movement of the plates created the vertical motion of the water.
 earthquake beneath the water along the ocean floor.

Tsunamis have small amplitude (wave heights). All the energy is accumulated under the water surface. Tsunamis have very long wavelengths that are often hundreds of kilometers long, which is why they can go unnoticed while at sea...typically when there is enough warning time for a tsunami, boats will travel away from the coast and harbors to further out to sea in order to not be affected. Once the wave reaches shallower water and the Continental Shelf, the wave height grown. This is when the tsunami can grow to up to be 30 foot wall of a wave! These waves travel at nearly 600 miles per hour. The footage of the tsunami moving along the shores of Sendai, Japan show just how fast the water came onto shore. People can't outrun the force and speed of this water.

Formation of a tsunami approaching the coast

How to predicting a tsunami

The Western coast line will be under a low tide during the projected time the tsunami is supposed to touch the shore of the West Coast. Mother Nature is fortunately working in our favor in that respect. However, low or high tide, a tsunami can still do damage to coastal areas. It just depends of the geography of the coastal land.  San Andres Fault, along the California coast is especially vulnerable during times like this when there is such a massive quake a few thousand miles away across the Pacific Ocean. The plates are in always in constant motion. Earthquakes occur everyday. Fingers crossed that isn't the beginning of a chain of events that triggers more significant earthquakes along the Ring of Fire. An event like this is an unnerving reminder that California is due for a significant earthquake.