A strong magnitude 7.7 earthquake rocked central Myanmar on March 28 at about 12:50 p.m. native time, leaving at the very least 144 individuals confirmed lifeless to date and triggering widespread injury throughout each Myanmar and Thailand. Buildings collapsed, roads broke and at the very least one dam and a bridge crumbled. A magnitude 6.4 aftershock adopted simply 10 minutes later.
With each international locations declared catastrophe areas, worldwide assist staff are scrambling to organize provides and assess the demise toll and damages. Marie Manrique, Myanmar program coordinator for the Worldwide Federation of Purple Cross and Purple Crescent Societies, informed reporters March 28 that the group is especially involved about damages to public infrastructure, together with large-scale dams.
An earthquake’s devastation is the end result not solely of its magnitude, but additionally its location and depth: Shallow quakes, even when they’re much less highly effective, could cause intense shaking on the floor floor, posing threats to infrastructure in populated areas. This quake had a trifecta of risks: It was highly effective; shallow, with the epicenter at simply 10 kilometers depth; and in a closely populated area with weak buildings and different constructions.
Listed below are three issues to find out about how and why this earthquake occurred.
It was a strike-slip earthquake.
This earthquake was most likely the results of sideways, or strike-slip, motion alongside the Sagaing Fault, a big fault that runs north to south by way of central Myanmar, in response to the U.S. Geological Survey’s Earthquake Hazards Program.
Strike-slip earthquakes happen when two blocks of tectonic crust are attempting to slip sideways previous one another; the blocks of crust could briefly lock as a result of friction, then wrench free, releasing a burst of seismic power by way of the bottom.
The Sagaing Fault is a part of a posh and unsafe plate boundary.
The fault marks the collision between the India tectonic plate, which incorporates the Indian subcontinent and a part of the Indian Ocean, and the Sunda Plate, a smaller little bit of crust that features components of Southeast Asia, together with the Malaysia Peninsula.
Because the India Plate slides northward, it grinds sideways towards the Sunda plate to the east, sometimes producing highly effective quakes. The Sagaing Fault area itself is rife with seismic hazards, and lots of giant strike-slip quakes have occurred within the space over the past century, together with a magnitude 7.0 in 1990 and a magnitude 7.9 in 1912, in response to the USGS. From 1930 to 1956, there have been six quakes higher than magnitude 7 on the Sagaing Fault itself that killed a whole lot.
The India Plate’s northward drive has additionally put it on a collision course with the Eurasian Plate. That ongoing conflict continues to push up the Himalaya mountain vary and the Tibetan Plateau. It has additionally brought about a number of the deadliest quakes within the Himalaya area, together with the 2005 Kashmir quake that killed tens of 1000’s of individuals.
Hazard zone
The March 28 earthquake’s epicenter (black star) was 10 kilometers belowground, nearest the town of Mandalay, Myanmar. Purple zones present areas of best shaking depth.
Liquefaction is a identified hazard within the area.
Areas with thick layers of free soil may be liable to liquefaction throughout quakes. That course of is a lethal interplay between seismic waves and the sediment that quickly causes the soil to behave like quicksand.
Earlier quakes on this area have triggered landslides and liquefaction that enormously added to the demise toll of these previous occasions — and should have contributed to this quake’s devastation, though it’s too quickly to know the extent of the damages.Â
