Anil Tiwari

Wadia Institute of Himalayan Geology | WIHG · Department of Geology & Geophysics

The observation of precursory signals of the 2021 Chamoli rock–ice avalanche provides an opportunity to investigate the multidisciplinary analysis approach of rock failure. On 7 February 2021, a huge rock–ice mass detached from the Raunthi peak at Chamoli district in Uttarakhand, India. The tragic catastrophe resulted in more than 200 deaths and si...

We investigate precursors to the 2021 Chamoli rock–ice avalanche in Uttarakhand, India, using radon and seismic signals. Through our analysis, we depict the dynamic changes within the source region, describing factors contributing to the avalanche. By examining recorded signals, we reconstructed dynamic nucleation phases, identified factors influen...

We image the high-resolution velocity structures of the crust and uppermost mantle beneath the western part of the Himalayan-Tibetan orogen through tomographic inversion of local and regional earthquake data. We herein reconstruct and present the tomographic image of the variable configuration of the Moho boundary beneath the Himalayan-Tibetan orog...

Between 2017 and 2019, the CSIR-NGRI, Hyderabad, Telangana, established a broad-band seismic-network with fifty-five 3-component broadband seismometers in the Himalayan region of Uttarakhand, India. Out of 55 three component broadband seismic (BBS) networks, we chose 17 for the present study. Using digital waveform data from twenty-one (21) regiona...

Characterizing the stress heterogeneity and crustal complexities are essential to understand the important aspects of rupture development and its propagation in a tectonically active region. We analyze a continuous seismic data (1999-2020) to estimate stress drops, b-value, fractaldimension (Dc) and focal mechanisms using a local network of 14 broa...

During the last few decades, there have not been any great earthquake in the Indian Himalayan region between two epicentre zones of 1934 Bihar-Nepal earthquake (M 8.4) and 1905 Kangra earthquake (M 7.8). However, in-between the central part of the Himalaya experienced several significant earthquakes: 1991 Uttarkashi earthquake (M 6.8), 1999Chamoli...

Between 2017 and 2019, the CSIR-NGRI, Hyderabad, Telangana, established a broad-band seismic-network with fifty-five 3-component bb seismometers in the Himalayan region of Uttarakhand, India. Out of 55 three component broadband seismic (BBS) networks, we chose 17 for the present study. Using digital waveform data from twenty-one (21) regional India...

The Garhwal-Kumaun region in the Himalaya in India lies in the Central Seismic Gap i.e. between the two great earthquakes of 1934 Bihar-Nepal and 1905 Kangra. This region is being continuously monitored through a seismic network and the geodetic data from GPS suggests a strong possibility of occurrence of Great earthquake occurring in this region....

The Himalayan collision zone has been prone to intense seismic activity as evidenced from the occurrence of four great earthquakes in the past century. Through this article, we have tried to revisit the source zones of the present as well as past major earthquakes along the Himalayan seismic gaps by analysing the earthquake activity and looking in...

On 7 February 2021, Chamoli district (Uttarakhand, India) was devastated by a deadly rock-ice avalanche that led to a large causality of more than 200 people and a huge economic loss. We found noteworthy sequence of precursory signals of main failure/detachment preceded by a dynamic nucleation phase. The rock-ice avalanche appears to have been init...

The Garhwal–Kumaun region (29°–31.5°N; 77°–81°E) in NW Himalaya lies in the Central Seismic Gap where the accumulated strain energy is sufficient for a future great earthquake. A broadband seismic network is continuously monitoring the seismic activity in this region and recorded a total of 3634 well located seismic events justified within the acce...

The Anderson's theory (Anderson, 1951) can be utilized to understand the allocation of principal stresses. For various tectonic regimes, the global seismicity trend for crustal earthquakes of less than 20 km depth suggests that the source fault inclination also plays a critical part in the propagation of the aftershocks in the subsurface rupture wi...

The measurement of site amplification of microtremors is an important tool for evaluating seismic hazard at local and regional level. The H/V spectral ratio (HVSR) method is applied to estimate the amplification of ground motion at resonance frequency. The fundamental resonance frequency is estimated at 8 different sites in study region and shows t...