Just recently, Japan was rocked by an 8.9 magnitude earthquake causing substantial loss of life and property, and inflicting serious damage in the country’s infrastructure, which would have been much worse if not for their long experience and preparation in earthquake safety.
But this earthquake is no less serious compared to other earthquakes in other countries, some of which lasted for more than 10 minutes and others reaching intensity 9+ on the Richter scale. Geologists have found out the chilling effect of Japan’s massive quake – shifting the earth’s axis by about 10 cm, and possibly triggering a series of earthquakes as a domino effect on other adjacent tectonic plates. Just minutes after the quake, a monster tsunami ensued, ravaging much of the Japan’s coastal communities.
People who are accustomed to Japan’s shaky grounds found this quake unusual. Prior to this catastrophic phenomenon, Japan was already battered by moderate quakes for seven days. Unlike the usual sporadic quakes, the succeeding incidents would go and on and then culminating in one of the most devastating earthquakes in Japan’s history.
The cause of earthquakes are orchestrated by forces beneath the earth’s surface. These forces cause the tectonic plates of the earth’s crust to move, sliding, slipping (subduction), pushing, or pulling away from each other which can be felt as mild tremors to violent earthquakes. Slippage or subduction, are notorious in causing the most destructive earthquakes and colossal aftershock waves. Japan’s 8.9 earthquake is an example of this.
How quakes happen? The chief danger of violent quakes and tsunamis happen in subduction faults. When one of the two colliding plates slips, or subducts underneath, the plates are said to be in a state of seismic quiescence, hence, no effects can be felt on the ground. At some point, however, the subducting plate moving underneath towards the opposite plate can get stuck, creating huge amount of tension . The longer it takes for the tension to released, the more deadly the ensuing effects would be.
When the plate finally reaches its limit of flexibility, the opposing plate would snap out violently, releasing tremendous amount of tension and stored energy, resulting in horrific earthquake and monster tsunamis.