Seismic records of earthquakes originating in India and worldwide are studied at NGRI to find patterns in seismicity, to prepare seismic hazard maps and to decipher the earth's structure and tectonics of the Indian region. In the year 1965, a seismological observatory was established in the NGRI campus which is the first seismological observatory in the centre of the Indian peninsular shield. Focal mechanisms of many earthquakes in the Indian subcontinent are obtained. Seismic zoning maps for the Indian and surrounding regions were prepared based on seismicity data. NGRI started the mapping of lithospheric structure using passive seismic experiments in different geological / tectonic terrains of India. Earthquake precursory and Tsunami modeling studies are being carried out at NGRI.