Scott: An 8.6 near Indonesia followed by an 8.2 aftershock. Then a 5.9 off the coast of Oregon. And shortly after that, a 6.5 followed by a 6.9 in Mexico. All these significant earthquakes in just a 24-hour period starting early Wednesday morning. And all the locations have something in common. They lie along a 25,000 mile ring, outlining much of the Pacific Ocean. It is where 90% of the world’s earthquakes and 75% of all the earth’s active and dormant volcanoes are found.
Wednesday’s two earthquakes in Indonesia were massive in power. Panic spread as people rushed into the streets. Hospitals and buildings were quickly evacuated. But in the end, almost no serious damage was reported.
Because of the size of the first quake and its powerful aftershock, tsunami warnings, for as far away as South Africa were quickly issued. But no major waves developed. Those tsunami warnings came fast because of a new system developed after one of the deadliest natural disasters of all time.
On december 26th 2004, Indonesia was hit by an even bigger earthquake, a magnitude 9.1. This one did create a tsunami, or giant wave. A wave that in some places was nearly 100 feet high. That tsunami killed more than 230,000 people across the Indian Ocean region. That is the same area where this week’s quakes hit. And this weeks’ were almost as powerful.
So, why no tsunami this time around? It is because of the type of quakes that took place. Back in 2004, two tectonic plates, or pieces of the earth’s crust, slammed into each other causing a massive up thrust, generating the shock waves that triggered a tsunami. But in this week’s earthquakes, the plates slid over one another, dramatically reducing shock waves and the risk of a tsunami. So this time, most people escaped with badly rattled nerves.
- What is the difference between an earthquake, a shock wave and a tsunami?
- How are earthquakes, shock waves and tsunami’s related?