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Introduction
Published in Sreevalsa Kolathayar, T.G. Sitharam, Earthquake Hazard Assessment, 2018
Sreevalsa Kolathayar, T.G. Sitharam
The seismicity of the Himalayan arc tectonic belt is connected with the underthrusting of the Indian plate beneath the Eurasian plate (Molnar and Tapponnier, 1979; Krishnan, 1953). The tectonically active interplate regions include the Himalayas and southern Tibetan plateau, the northwest frontier province of the Indian plate (Nath and Thingbaijam, 2010; Kayal, 2008). The movement of the Indian plate in the northeast direction and its collision with the Eurasian plate has created the largest mountain range in the world, the Himalayas, with an average height of 4600 m and the most prominent and highest plateau region in the world – the Tibetan plateau. The Indian plate once was one of the fastest moving plates in the world. Before its collision with the Eurasian plate, it attained a very high velocity of around 20 cmyr−1 (Kumar et al., 2007). The current movement of Indian plate is estimated to be around 5 cm yr−1. The collision and the subsequent formation of the Himalayas and the Tibetan plateau are associated with very high seismicity.
Earthquakes and Associated Landslides in Pakistan
Published in Ramesh P. Singh, Darius Bartlett, Natural Hazards, 2018
Shah F. Khan, Muhammad Asif Khan, Ulrich Kamp, Lewis A. Owen
According to this general tectonic setting, Pakistan can be divided into five seismotectonic provinces: (1) Pamir–Hindu Kush, (2) Karakoram–Himalaya, (3) Axial Belt (Waziristan–Sulaiman–Kirthar Ranges), (4) Makran and (5) Rann of Kuchchh (Figure 14.4). All these are part of the Indian-Eurasian plate boundary except for the Rann of Kuchchh, which is an intraplate seismotectonic province within the Indian plate. Each of these seismotectonic provinces has generated major earthquakes in the past two centuries, and with the exception of the Rann of Kuchchh province, all have experienced earthquake-triggered landslides. Rann of Kuchchh, despite being dominantly a low-lying gentle terrain, is susceptible, like the other four provinces, to earthquake-triggered surface disturbances, such as surface ruptures, differential uplift and subsidence, lateral spreading and liquefaction (Rastogi 2001; Biswas 2005).
Tunnels in the Himalaya
Published in Xia-Ting Feng, Rock Mechanics and Engineering, 2017
The Indian subcontinent is surrounded in the north by a lofty mountain chain known as the Himalaya. The Himalayan range with NW-SE general trend was formed, according to the theory of ‘Continental Drift’, by the collision of the Indian Plate with the Eurasian Plate. The Indian plate is known to be moving toward north at a rate of approximately 5 cm per year. This collision, which began with the first contact about 40 million years ago, caused the sediments of the intervening Tethys Sea and the Indian Shield to be folded and faulted into the lofty peaks and outliers visible in the lesser Himalaya. Since the northward shift of the Indian plate is still continuing, the mountain building process is still continuing and the zone is still active seismically. On the basis of its average height from mean sea level (MSL), from south to north, the Himalayan range and the rock formations are divided as per Table 1 and shown in Figure 1. Similarly, geographically from west to east, the Himalaya is divided as given in Table 2.
3D Crustal Velocity Model for Ground Motion Simulations in North-East India
Published in Journal of Earthquake Engineering, 2021
S. Sangeetha, J. Dhanya, S. T. G. Raghukanth
North-East India is one of the most seismically active regions in the world. The active under thrusting of the Indian plate into the Eurasian plate contributes to the tectonic complexities of the region [Chen and Molnar, 1990; Bilham and Gaur, 2000; Bilham, 2004]. The tectonic movements have resulted in major thrust faults along the boundaries and several strike slip faults along Arakan-Yoma range. The records show that the region has experienced more than 3000 earthquakes of magnitude (Mw) > 4, which include numerous strong to major earthquakes [Nandy, 2001; Raghukanth, 2011; NEIST report, 2013; PESMOS 2005–2015 catalogue, Rao, 2015]. The two great earthquakes that occurred in the province are the 1897 Mw 8.7 Assam earthquake and 1950 Mw 8.630 Assam–Tibet earthquake. Hence, the Global Seismic Hazard Assessment Program (GSHAP, 1992–1999) classifies this region as a zone of high seismic risk with possible peak ground acceleration of 0.35–0.4g [Bhatia et al., 1999]. According to IS 1893:2002, the region belongs to seismic zone V, indicating very severe seismic activity.
Solar map of India under clear sky conditions
Published in International Journal of Sustainable Energy, 2019
Neelam Rathore, N. L. Panwar, Amor Gama, Fatiha Yettou
India lies on the northern portion of the Indo – Australian plate i.e. Indian Plate. India is located north of the equator and its latitude extends from 8°4′ to 37°6′ north whereas longitude range extends from 68°7′ to 97°25′ east. India covers an area of 3,287,263 square kilometres which is seventh largest country in the world. The extension of India is 3,214 Km from north to south and 2,933 Km from east to west. (Kumar and Chopra 2009). There is difference of time between eastern and western part of India due to gigantic east –west extension of India. Due to difference of 30° longitude between eastern and western part of India, there is time gap of 2 hours between them. Therefore, it is due to this reason that sun rises 2 hours earlier in Arunachal Pradesh than in Gujarat. (Kumar et al. 2005). Table 1 enlists various Agro climatic zones of India with representative states.
Probabilistic seismic hazard analysis of the North-East India towards identification of contributing seismic sources
Published in Geomatics, Natural Hazards and Risk, 2023
Niranjan Borah, Abhishek Kumar
NE India is one of the most EQ-prone regions across the globe. Notable EQs that caused induced effects in terms of ground shaking, landslides, liquefaction and infrastructural damage include 1897 Assam EQ (Mw-8.1, highest MSK intensity-IX, EMS intensity-X), 1869 Cachar EQ (Mw-7.6, Highest EMS intensity- IX), 1923 Meghalaya EQ (Ms-7.1) , 1930 Dhubri EQ (Mw-7.1), 1943 Assam EQ (Ms-7.2), 1947 Arunachal Pradesh EQ (Ms-7.7), 1950 Assam EQ (Mw-8.4), 1988 Manipur EQ (Mw-7.2), 2009 Assam EQ (Mw-5.1), 2011 Sikkim EQ (Mw-6.9) (Baro and Kumar 2015; Raghu Kanth et al. 2011; Kayal 2008; Oldham 1899; Fahmi et al. 1988; N. N. Ambraseys and Douglas 2004; England and Bilham 2015; Nicolas Ambraseys and Bilham 2003; Sabri 2002) etc. Recently, on April 28, 2021, an EQ of 6 Mw (as per USGS) occurred in Dhekiyajuli, Assam, triggering significant liquefaction. Before this EQ, another EQ (Mw-6.7) occurred in 2016 near Imphal, causing considerable damage (Gahalaut and Kundu 2016). High seismic activity of NE India is primarily due to the presence of two plate boundaries: the Indian Plate and the Eurasian plate subduction zone in the north, and the Indian Plate and the Burmese plate subduction zone in the east. In the light of significant EQs witnessed in the NE, IS-1893 (2016) part 1 classifies the entire NE India (excluding the state of Sikkim) as seismic zone V, the region of highest seismic hazard in the Indian subcontinent. However, numerous seismic hazard studies highlight that the seismic hazard across NE is not-uniform. The subsection below summarises various Seismic Hazard Analysis (SHA) studies for the NE and their associated limitations.