Under the Earth: Japan’s Tohoku Earthquake and the Resulting Knowledge

There are some places on the planet where natural disasters seem to occur more frequently. Coastal areas, for example are a hub for hurricane activity and Island are susceptible to tsunamis. There are many factors at play in the environment, many of which were undetectable in the recent past. Earthquakes are a way of life for many areas of the globe. The tiny country has made many advancements in earthquake detection and seismic research over the years. The March 11, 2011 Tohoku earthquake, however, alerted scientists to something different.

Data Collection 

Scientists knew something was different about this earthquake, but they weren’t sure what it was. The earthquake stemmed from a well-known fault area, however, the results were not as expected. An earthquake of a magnitude of seven or eight was the expectation. What ensued, was a level nine. This fault line had been studied before, with research pointing to a regular buildup of pressure resulting in an earthquake.

While the incident was traumatic, there were extensive numbers of sensors in place that recorded the activity that day. GPS recorders recorded activity from the floor of both the land and sea, while other sensors focused on the height of the tsunami. This information gives researchers a much better idea of what is happening on this particular fault line, helping them to better prepare for future complications.

Both high- and low-frequency waves were recorded, giving the indication of different levels of stress on various areas of the fault. This is not what scientists previously thought would happen. The high-frequency waves were not coming from the area of the break, they were coming from the area still intact. Since high-frequency waves are known to be connected to high levels of stress, scientists now know better what to look out for.

The Confusion 

Scientists were able to tell how much of the fault slipped during the earthquake. The numbers came out to about 250 kilometers. This amount does not match up to severity of the earthquake. In fact, researchers concluded that it should have taken twice this amount of slippage to cause the disaster that happened.  It turns out that the majority of the slip was in an even smaller area of the total area recorded. This small section appeared to be somewhere between 50- 100 kilometers long. All of this data contradicted the actual event. Previous research, and these new findings still showed that an earthquake with a magnitude of nine should not be possible in this area.

Further Findings 

Further inspection has led to the hypothesis that a part of the plate in question is not just slipping, but sinking as well. This information adds a new level of complication to the equation. It is possible that this sinking section became stuck for hundreds of years, causing pressure to collect the entire time. An earlier theory assumed that the plate was slipping gradually without any side effects. Scientists have had to change their way of thinking, as well. In a humbling moment, they admit that this act of nature proves the possibility of a megaquake in many parts of the world. They do understand that what they were recording beneath the surface of the earth did coincide with what presented on top. This fault line is offshore and had been studied thoroughly over the years.

Japan’s regular earthquake history was thought by scientists to give a clear indication of the future disasters. They are now considering the possibility that they did not look far enough back at the history of Japan’s earthquakes. Data is only available from a certain point in history, and it may not be possible to get clear evidence of earlier earthquakes of this magnitude. This attitude applies with all faults, after what has happened. The date for this particular fault line goes back a little over 100 years. Scientists now think they need to look at thousands of years. The data they have is much too small of a time frame in the earth’s history.

The Tohoku earthquake was a tragedy that caused almost $200 billion in damage. Hundreds of thousands of people lost their homes as well. Around 20,000 deaths were confirmed with thousands of people missing. Scientists have gained a new understanding of the possibilities after the incident, and are unlikely to underestimate planet earth again. The excellent recordings during this tragedy have led to the better understanding of this particular subduction zone, as well as others.

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