WHY IN NEWS ?
- Recently the most powerful earthquake ever recorded in Morocco struck late Friday night, killing more than 2,400 people
MORE ABOUT THE NEWS :
- The quake was of magnitude 6.8 with an epicentre located in the Al-Haouz province, in the Atlas Mountains of the historic city of Marrakech, according to the US Geological Survey.
- Over the past 48 hours, at least two dozen aftershocks have hit the region with the strongest being magnitude 4.9, the agency added.
- The USGS reported that the epicentre of the Friday earthquake was roughly 18.5 km below the Earth’s surface, though Morocco’s own seismic agency pegged the depth at 11 km.
WHAT CAUSED THE EARTHQUAKE ?
- Such quakes occur due to the northward convergence of the African plate with respect to the Eurasian plate along a complex plate boundary.
- With respect to Friday’s quake, the USGS attributed it to “oblique-reverse faulting at shallow depth within the Moroccan High Atlas Mountain range”.
- During the earthquake, the edge that lies towards the mountains slid over the other, pushing the mountainside up, a knock-on consequence of built-up tension between the African and Eurasia plates over time.
- A fault is a fracture or zone of fractures between two blocks of rock.
- Faults allow the blocks to move relative to each other, causing earthquakes if the movement occurs rapidly.
- During a quake, the rock on one side of the fault suddenly slips with respect to the other.
WHY EARTHQUAKES CANNOT BE PREDICTED ?
- An accurate prediction of an earthquake requires some sort of a precursory signal from within the Earth that indicates a big quake is on the way.
- Moreover, the signal must occur only before large earthquakes so that it doesn’t indicate every small movement within the earth’s surface.
- Currently, there is no equipment to find such precursors, even if they exist.
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