2 Uttarakhand districts and four of Kerala among top 10 landslide prone districts, ISRO Survey | Latest news India

Uttarakhand’s Rudraprayag and Tehri Garhwal districts have the highest density of landslides in the country, a satellite-based survey of 147 most vulnerable districts by the National Remote Sensing Center (NRSC) found, with the western Himalayan region most vulnerable to landslides.

“Rudraprayag district of Uttarakhand state, which has the highest landslide density in India, also has the highest exposure in terms of total population, working population, literacy and numeracy. of houses (from landslides),” said the study based on ISRO satellite maps.

Of the 10 most landslide-prone districts, four are in flood-prone areas of Kerala, two in Jammu and Kashmir and two in Sikkim. In fact, after the Himalayas, the Western Ghats, which have seen large-scale development in the past few years, have the highest landslide density.

For the first time, NRSC scientists assessed the risk based on 80,933 landslides recorded between 1988 and 2022 in 147 districts of 17 states and two Union Territories to develop the Landslide Atlas of India.

The risk analysis was based on human and livestock population density, which indicates the impact of these landslides on people and shows the most landslide prone areas in the country. The atlas uses ISRO’s satellite data to map all seasonal and event-based landslides, such as the Kedarnath disaster in 2013 and the landslides caused by the Sikkim earthquake in 2011.

The risk of landslides has intensified over the years due to environmental degradation and extreme weather events such as high-intensity rainfall, which has been exacerbated by climate change, scientists said.

“In recent years, we have seen unplanned development in the Himalayan hills and the Western Ghats, with little regard for the environment and forests. Its impact, coupled with extreme rainfall, is visible through increasingly large landslides and landslide incidents from Joshimath to Doda to Darjeeling,” said Ravi Chopra, former head of the Supreme Court-appointed panel on the Chardham highway project in Uttarakhand.

The new study recorded 80,933 landslide hot spots between 2000 and 2022, with maximum 12,385 in Mizoram, followed by 11,219 in Uttarakhand, 7,280 in Jammu and Kashmir and 1,561 in Himachal Pradesh. Among the southern states, Kerala recorded the highest number of landslide hot spots (6,039).

Using satellite data, the National Remote Sensing Authority has recorded the total number of landslides in states between 2010 and 2022, with Uttarakhand recording the highest number of landslides during the period. Within the state, Rudraprayag and Tehri districts recorded the highest number of landslides, the study said.

“The main cause of landslides in Rudraprayag and Tehri districts is the use of dynamite to blast rocks, as it creates cracks in the hills,” said Bipin Kumar, an environmentalist from Mussoorie. Many slopes in these two districts are already filled with old landslide material and are unstable and vulnerable to new landslides, he added.

“One of the major causes of landslides in Rudraprayag district is the irresponsible method of cut and dump for road cutting, which is destabilizing many slopes,” said Hemant Dhiyani, who was a member of the Supreme Court committee formed in 2014 to study the impact. Hydroelectric projects on the Himalayas.

In Tehri, he said, reservoir-induced instability, particularly around the Tehri hydroelectric project, is also causing slope instability, leading to landslides.

The Dehradun-based Wadia Institute of Himalayan Geology has prepared a spatial distribution of landslide-prone areas in the Uttarakhand Himalaya, according to which 51% of the state is in high and very high landslide-prone areas, 22-23% in moderate areas and 26% in -27% in low and very low landslide prone areas.

Eight other districts in the top 10 affected districts are Thrissur in Kerala, Rajouri in Jammu and Kashmir, Palakkad in Kerala, Poonch in Jammu and Kashmir, Malappuram in Kerala, South and Eastern districts of Sikkim and Kozhikode in Kerala. The list of 147 districts includes 64 districts of North-East.

The study states that a large part of the Himalayan region is susceptible to landslides. It is the high population density, major pilgrimage routes and tourist spots that worsened the impact of the disaster in Jammu and Kashmir, Himachal Pradesh and Uttarakhand. Uttarakhand alone has reported more than 7,750 extreme rainfall events and cloud bursts since 2015, most in the last three years, killing more than 230 people.

India is the third most landslide-prone country in the world, with more than one person dying every 100 square kilometers due to landslides every year, the study said. The other countries are Colombia, Tajikistan and Nepal.

The impact of landslides is more pronounced in the western coasts of North and South America, Central America, the Alpine regions of Italy, France, Switzerland and Austria in Europe, the Himalayan region of India, Nepal in Asia and parts of Central Asia, mainly because development activities have been encouraged to meet the growing needs of the population, the report said. has been

According to the study, about 0.42 million sq km, or 12.6% of India’s land area, excluding snow-covered areas, is vulnerable to landslides. Of this, 0.18 million sq km falls in the North Eastern Himalayas, including the Darjeeling and Sikkim Himalayas; 0.14 million sq km in the North West Himalayas (Uttarakhand, Himachal Pradesh and Jammu and Kashmir); 0.09 million sq km in the Western Ghats and Konkan Hills (Tamil Nadu, Kerala, Karnataka, Goa and Maharashtra) and 0.01 million sq km in the Eastern Ghats in Aruku area of ​​Andhra Pradesh.

“In India, landslides mostly occur during the monsoon season. The Himalayas and Western Ghats are highly susceptible to mass movement due to hilly topography and heavy rainfall,” the study said.

In India, such disasters mostly occur during the monsoon season, due to heavy rains that cause landslides that can be affected by the use of heavy machinery in development projects. However, the NRSC says in the future it will be able to map slow-moving mountain slopes, where the risk of landslides is high.

(With inputs from Neeraj Santoshi in Dehradun)