LANDSLIDE ATLAS OF INDIA - GEOGRAPHY
News: ISRO
releases the Landslide Atlas of India: Which states, regions are most
vulnerable
What's in the news?
● With
a steady rise in the number of extreme weather events, especially heavy
rainfall capable of triggering landslides and floods, the Indian Space Research Organization (ISRO) recently released the
Landslide Atlas of India, a detailed guide identifying landslide hotspots in
the country.
Key takeaways:
● Uttakarkhand,
Kerala, Jammu and Kashmir, Mizoram, Tripura, Nagaland and Arunachal Pradesh
reported the highest number of landslides during 1998 – 2022.
Findings:
● Mizoram topped the list,
recording 12,385 landslide events in the past 25 years, of which 8,926 were
recorded in 2017 alone.
● Likewise,
2,071 events of the total 2,132 landslides reported in Nagaland during this
period occurred during the 2017 monsoon season.
● Manipur,
too, showed a similar trend, wherein 4,559 out of 5,494 landslide events were
experienced during the rainy season of 2017. Of the total 690, Tamil Nadu
suffered 603 landslide events in 2018 alone.
● Among
all these states, an alarming situation is emerging from Uttarakhand and
Kerala.
● The
number of districts with the maximum landslide exposure are in Arunachal
Pradesh (16), Kerala (14), Uttarakhand and Jammu and Kashmir (13 each),
Himachal Pradesh, Assam and Maharashtra (11 each), Mizoram (8) and Nagaland
(7).
● Kerala
has been consistently reporting massive landslides since it suffered the
century’s worst floods in 2018. The year-wise landslide events here are 2018
(5,191), 2019 (756), 2020 (9) and 2021 (29).
● NRSC
ranked Rudraprayag in Uttarakhand at the
top of 147 vulnerable districts. It has the highest landslide density in
the country, along with having the highest exposure to total population and
number of houses.
Go back to basics:
Landslides:
● Landslides
are natural disasters occurring mainly in mountainous terrains where there are
conducive conditions of soil, rock, geology and slope.
● A
sudden movement of rock, boulders,
earth or debris down a slope is termed as a landslide.
Causes of Landslides:
● Natural causes
that trigger it include heavy rainfall, earthquakes, snow melting and undercutting
of slopes due to flooding.
● Landslides
can also be caused by anthropogenic
activities such as excavation, cutting of hills and trees, excessive
infrastructure development, and overgrazing by cattle.
Factors influencing Landslides:
● Some
of the main factors that influence landslides are lithology, geological
structures like faults, hill slopes, drainage, geomorphology, land use and land
cover, soil texture and depth, and weathering of rocks.
● All
these are factored in when a landslide susceptibility zone is earmarked for
planning and making predictions.
Vulnerability of India:
● India is considered among
the top five landslide-prone countries globally,
where at least one death per 100 sq km is reported in a year due to a landslide
event.
● Rainfall variability
pattern is the single biggest cause for landslides
in the country, with the Himalayas and the Western Ghats remaining highly
vulnerable.
● Excluding
snow covered areas, approximately 12.6
percent of the country’s geographical land area (0.42 million sq km) is prone
to landslides.
● As
many as 66.5 percent of the landslides are reported from the North-western Himalayas, about 18.8
percent from the North-eastern
Himalayas, and about 14.7 percent from the Western Ghats.
● Nearly
half of the country’s landslide-prone area (0.18 sq km) is located in the
states of Assam, Arunachal Pradesh, Sikkim, Meghalaya, Mizoram, Manipur,
Tripura and Nagaland. Uttarakhand, Himachal Pradesh, Jammu and Kashmir cover
0.14 million sq km of the total landslide-prone areas, whereas Maharashtra,
Goa, Karnataka, Kerala, and Tamil Nadu account for 0.09 million sq km.
● A
relatively small area (0.01 million sq km) of the Araku region in Andhra
Pradesh along the Eastern Ghats, too, reports landslide events.
● In
the Western Ghats, despite fewer events, landslides were found to be making
inhabitants significantly vulnerable to fatalities, especially in Kerala.
Impacts:
● Considered
among the most frequent natural disasters, landslides are extremely hazardous, posing a threat to human and animal lives,
damaging property, roads and bridges, disrupting communication lines and
snapping power lines.