Numerical Simulation based modeling of 2004 Andaman-Sumatra Tsunami to understand the tsunami hazard along the coastline of Mainland India

Natural hazards affect the progress towards sustainable development. Increasing effects ofnatural hazards viz. earthquakes, tsunamis, floods, landslides around the world has a directsocial, economic and environmental impact. The people living in the coastal areas of thetropics are exposed to various types of natural hazards of which the most devastating onesinclude high energy events such as earthquakes and tsunamis. The lithosphere of the Earth iscomposed of seven major and minor tectonic plates colliding, subducting or rifting apart withrespect to one another. This phenomenon has resulted in several tectonic plate boundariesaround the globe. The plate boundaries marked by subduction zones have produced numerousmega-earthquakes and associated transoceanic tsunamis. In the domain of the Indian sub-continent, the ongoing collision between the Indian plate and the Eurasian plate has resulted in the formation of the Himalayas in the north, and asubduction zone in the southwest along the Sumatra-Andaman trench. In the last fewdecades, Indian sub-continent experienced several devastating earthquakes with Mw >7.5. These events are viz. the 2001 Bhuj earthquake (Mw7.6) in Stable Continental Region (SCR)of Western India; 2005 Muzaffarabad earthquake (Mw7.6) in Kashmir; 2015 Gorkhaearthquake (Mw7.8) along the active plate-boundary along Himalaya; and 2004 Sumatra-Andaman earthquake (Mw9.3) and associated transoceanic tsunami in the Indian oceandirectly affected the people and their property. The Indian Ocean Tsunami (IOT) directlyaffected the coastlines of Indian Mainland, Sri Lanka, Thailand, Indonesia, Maldives andSomalia, killing about 280,000 people. The whole coastline of India faces the danger oftsunamis from the tsunamigenic subduction zones lying close to the Indian Subcontinentwhich include the Arakan subduction zone and Andaman-Sumatra subduction zone. Thenumerical study of tsunami provides an insight of the assessment of the level of risk to whichthe coastal regions are exposed. In the present study attempts have been made to know about the effects of probable tsunamison the Indian coastline considering the arrival time, wave height and directivity of tsunami waves as well as the inundation of the waves inland at the coasts of Andaman andmainland India. Keeping these in mind, modeling is carried out for 2004 Sumatra-Andamantsunami is generated as well as validated. Modeling is likean art which can be applied to generate past events. Numerical Modeling based on Non-linearShallow Water (NSW) help to know about the wave height and directivity of tsunami wavesbased on which time required to reach the tsunami waves at a particular location can beestimated. Tsunami height observed along the south eastern coast of Mainland India ranges between 2 to 3 m for 2004 tsunami. It took around 120 minutes to reach the coastline of Mainland India and hit the coastal structures. If a transoceanic tsunamioccurs in Indian Ocean having epicenter near Andaman Island, it will cause completedevastation of south eastern coast of Mainland India. This study will helps in formulation and design of mitigation measures with the early warning systems, which may eventually lead toless loss of life and damages to the property.