Rapid determination of earthquake magnitude and displacement field from GPS-observed coseismic offsets for tsunami warning

Rapid assessment of the tsunamigenic potential of an earthquake as well as a prediction of the likely propagation pattern of the tsunami support reliable tsunami early warning. Availability of the coseismic surface displacements with low latency can support the assessment of the tsunamigenic potential of an earthquake and improve predictions of the propagation pattern of the tsunami. We use a fingerprint methodology for the rapid determination of the static co-seismic displacement field and an unbiased magnitude estimate from GNSS displacements. The fingerprint methodology requires a priori knowledge of the faults potentially involved in a rupture. The known faults are parametrized with standard elements and for each element so-called fingerprint functions are computed for unit strike and dip slips. After an event, the model space of all reasonable fault-element combinations is searched for the element-slip combination best fitting the observed displacements, which provides the best estimate of the earthquake displacement field and magnitude. Here we describe the fingerprint methodology and discuss the limitations of the current system.