Tsunami warning in French Polynesia during the 2009 Samoa event

An effective tsunami warning was in effect in French Polynesia for the big Samoa event on September 2009; a rapid warning was generated from the seismic parameters obtained via near real-time processing. Different methods were used to characterize and quantify the source parameters like: evolving scalar moment along the time, average mantle magnitude Mm, slowness, and use of the new concept of magnitude with the W phase. The expected tsunami amplitudes were estimated from seismic parameters such obtained, and were communicated to Civil Defense; a red warning was then broadcasted to population during about one hour (2 hours in Marquesas). In fact, French Polynesia was spared by the tsunami, with relatively weak amplitudes in Society Island, and, as expected, larger ones in Marquesas (justifying the this warning and state of watch). Numerical simulations involving different seismic source models, were used in a later stage to explain the observed tsunami amplitudes.