Topics Covered: Important Geophysical phenomena such as earthquakes, Tsunami, Volcanic activity, cyclone etc.
Previously unknown faults at the foot of the Himalaya discovered
An oil and gas exploration company has helped geologists discover a series of faults at the foot of the Himalaya.
- This fault system lies in the southeastern region of Nepal and has the potential to cause earthquakes in the densely populated country.
Significance of these findings:
This network of faults show that the Himalayan deformation reaches further [about 40 kilometres further south] than we previously thought.
- It highlights the need to look below the surface, and further afield, to fully understand earthquakes and structures within the Himalaya.
Will this fault system affect India?
The newly discovered system doesn’t appear to extend into India, but seismic waves from an earthquake occurring on them might affect regions of India near the border.
- However, other similar faults might be present elsewhere along the southern edge of the Himalaya and might extend beneath northern India.
What is a fault?
A fault is a fracture or zone of fractures between two blocks of rock.
- Faults allow the blocks to move relative to each other.
- This movement may occur rapidly, in the form of an earthquake – or may occur slowly, in the form of creep.
- Previously unknown faults at the foot of the Himalaya discovered.
Faults are related to the movement of Earth’s tectonic plates. The biggest faults mark the boundary between two plates.
There are three kinds of faults:
- Strike-slip: indicate rocks are sliding past each other horizontally, with little to no vertical movement. Both the San Andreas and Anatolian Faults are strike-slip.
- Normal fault: create space. Two blocks of crust pull apart, stretching the crust into a valley. The Basin and Range Province in North America and the East African Rift Zone are two well-known regions where normal faults are spreading apart Earth’s crust.
- Thrust (reverse) faults: slide one block of crust on top of another. These faults are commonly found in collisions zones, where tectonic plates push up mountain ranges such as the Himalayas and the Rocky Mountains.
Strike-slip faults are usually vertical, while normal and reverse faults are often at an angle to the surface of the Earth.
- What are faults? Types?
- What is an epicentre?
- Name the major plates.
- Emergent vs Submergent coastlines.
- Most destructive earthquake waves.
Discuss why Himalayan region is prone to earthquakes.
Sources: the Hindu.