Earthquakes

1.Seismic Zones in India: India is divided into four seismic zones (Zone II, III, IV, and V), with Zone V being the most seismically active, covering approximately 11% of the country’s land area. The Himalayan region, which includes states like Uttarakhand, Himachal Pradesh, and the northeastern states, along with parts of Gujarat and Jammu & Kashmir, falls under Zone V. For example, the northeastern states experience frequent seismic activity due to their location on the boundary between the Indian and Eurasian tectonic plates.

2.Major Earthquakes and Their Impacts: India has experienced several devastating earthquakes, such as the 2001 Gujarat earthquake (magnitude 7.7) that resulted in over 20,000 deaths and caused economic losses estimated at $5 billion. The 2015 Nepal earthquake, with a magnitude of 7.8, also had significant impacts in northern India, including the deaths of over 100 people in Bihar and Uttar Pradesh, and damage to historical monuments in Sikkim and West Bengal.

3.Preparedness and Mitigation Strategies: Preparedness measures include enforcing building codes to ensure earthquake-resistant construction, particularly in high-risk zones. For instance, the National Building Code of India provides guidelines for seismic-resistant design of structures. Regular seismic risk assessments and public awareness programs, such as the National Earthquake Risk Mitigation Project (NERMP), are crucial. Mitigation strategies involve retrofitting existing structures, land-use planning, and establishing early warning systems like the ones implemented in Delhi and Uttarakhand.

Floods

1.Riverine Floods: Riverine floods are common in India’s major river basins, such as the Ganga, Brahmaputra, and Mahanadi. These floods are often caused by excessive monsoon rainfall. For example, the 2017 Bihar floods affected over 17 million people and led to the displacement of nearly 800,000 individuals, primarily due to the overflowing of the Ganga and its tributaries.

2.Flash Floods and Urban Flooding: Flash floods occur suddenly due to intense rainfall, often in hilly or urban areas, causing rapid water accumulation. Urban flooding is increasingly common in cities like Mumbai, where the 2005 floods caused by 944 mm of rainfall in a single day resulted in over 1,000 deaths and economic losses exceeding $1.2 billion. Chennai also experienced severe urban flooding in 2015, leading to over 500 deaths and widespread damage.

3.Flood Management in India: Flood management strategies include the construction of embankments, dams, and reservoirs to control water flow, as seen in the construction of the Hirakud Dam on the Mahanadi River. The development of flood forecasting and early warning systems by the Central Water Commission has been instrumental in reducing flood impacts. The National Flood Control Program, which began in 1954, and the Integrated Flood Management approach emphasize the use of both structural and non-structural measures to mitigate flood risks.