Assam, Tibet Mg 8.6 Quake 1950
Hot on the heels of the China’s magnitude 6.1 earthquake last week, today marks the 64 anniversary of what is known as the Assam or Medog quake of 1950. The epicenter was actually in Rima, an area claimed at the time by Tibet and China, but effects were felt across the area with even substantial damage caused in northeastern India.
There were an estimated 30,000 casualties and 1,526 people reportedly lost their lives across the three countries. 70 villages were destroyed throughout the Abor Hills, landslides obstructed the Subansiri river creating a natural dam which broke, causing a 7ft wave which submerged villages in its path.
It was not just the impact on humans that made this earthquake so notable, it also holds great geological significance. The 10th largest quake of the 20th Century, it was also the largest known earthquake not to be cause by an oceanic subduction zone making us rethink how these large quakes can be caused. Aftershocks went on for several years, many of which were significant in their own right reaching over a magnitude 6. One which had an epicenter much closer to Assam causing further panic as journalists claimed it was actually bigger then its predecessor. These aftershocks also ranged over much wider geographic area than expected, further showing our need to understand earthquakes in areas of continental convergence,
Figure 1. Shows how far from the epicenter the S-waves were felt. http://www.toptensthings.com/2012/04/top-10-biggest-earthquakes-in-the-last-100-years/ accessed 15/08/14
Figure 2. Displacement caused by the quake http://besttop10tip.com/top-10-biggest-earthquake-world-history/ accessed 15/08/14