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Unusual April 2012 Indonesian Earthquake may have broken tectonic plate and created new plate boundary

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Indonesian tectonic platesThe April 11, 2012 series of Earthquakes in Indonesia may have been a bigger event than originally thought – they may have broken the tectonic plate. The largest of the quakes was a magnitude 8.7 offshore quake that produced stronger ground-shaking than any earthquake in history. Scientists found it odd that it triggered several earthquakes around the world. Ross Stein of the U.S. Geological Survey remembers the evening quite well:

"I was having dinner with my wife at a restaurant a few hours after this earthquake had occurred, and I kept getting paged. And I would look and see that a large earthquake had occurred somewhere around the world. And it just seemed very, very odd that we were having this run of earthquakes of magnitude 5 and larger in this short space of time."

Stein reported in Nature magazine that the big quake triggered 16 moderate quakes around the planet. Aftershocks are common but triggering distant quakes is a very rare occurrence. The plate movement and energy released from the quake was unusual too.

NPR reported:

“The energy from this quake was all released in about two minutes, compared with eight minutes for the quake that triggered the deadly Indian Ocean tsunami in 2004. And while most quakes of this size move the ground up and down — which can cause tsunamis — ground movement during the April quake was side to side. This is the largest strike-slip, or San Andreas-like earthquake ever recorded.”

What was most unusual about the 8.7 event was that it ruptured on four different faults at the same time and may have created a new plate boundary in the process.

Sources: Nature Magazine, NPR, The Register