Hydroacoustic observations of Indian earthquake provide new data on T-waves



The magnitude 7.8 earthquake that devastated the Bhuj area of western India on 26 January 2001 was recorded not only by seismometers around the world, but also by a new hydroacoustic array in the Indian Ocean. This array, located 3290 km south of the epicentral area (see Figure 1a), consists of two tripartite hydrophone arrays surrounding the atoll of Diego Garcia at the southern end of the Chagos Plateau. Installed as part of the hydroacoustic monitoring network for the Comprehensive Nuclear Test Ban Treaty's International Monitoring System (IMS), the array has since been recording the acoustic T-wave signals generated by many shallow earthquakes below the Indian Ocean since the summer of 2000.