Locating earthquakes with amplitude: Application to real-time seismology

Earthquakes are traditionally located using travel times. However, since the -motion amplitude generally decays with the distance from the source, it also be possible to locate earthquakes using amplitude data. Amplitudes affected by many factors other than the distance, so that we do not expect to able to locate the epicenter, the location of the initial rupture, very accurately amplitude data. However, locating earthquakes with amplitudes has its merits: (1) For postearthquake emergency services, it is often more important know the spatial distribution of strong-motion parameters such as peak and peak velocity than the rupture initiation point itself (National Council, 1991). This is especially true for thrust earthquakes (e.g., 1971 San Fernando earthquake; 1987 Whittier Narrows earthquake) or events large rupture zones. (2) The amplitudes are usually much easier to than the arrival times, especially for events with complex rupture or with immediate foreshocks in which event association can be . For application to real-time earthquake information systems such as (Caltech/USGS Broadcast of Earthquakes; Kanamori et al., 1991), the method could provide a quick and robust way to send useful information emergency operations. Here, we report a few examples and propose a for future implementation in a CUBE-type system.