National Seismological Network in India for Real-Time Earthquake Monitoring

Abstract

\n The National Seismological Network (NSN) of India has a history of more than 120 yr. During the last two decades, the NSN has gone through a significant modernization process, involving installation of seismic stations equipped with a broadband seismograph (BBS) and a strong-motion accelerograph (SMA). Each station has a very-small-aperture terminal connectivity for streaming data in real time to the central receiving station (CRS) in New Delhi. Seismic data recorded by the network are analyzed continuously on 24×7 basis to monitor the earthquakes in India and its adjoining regions. In this article, we present details of BBS and SMA network configurations; data streaming from the field seismic stations to the CRS for analysis; and the automatic and manual publication of the earthquake parameters including location coordinates, focal depth, time of occurrence, and magnitude, etc. Details of historically significant analog seismic charts and the seismic catalog, which includes more than 34,000 events with magnitude Mw\xa01.7–9.3 since 1505, are provided. The national network of India has been strengthened over the years and is now capable of estimating the main earthquake source parameters within ∼5–10min with an average of about 8.0 min. The spatial analysis of minimum magnitude of completeness further indicates a significant enhancement in minimum threshold magnitude detection capability of the network in recent decades.