Tsunami warnings issued by the Joint Australian Tsunami Warning Centre (JATWC) are derived from a database (T2) consisting of more than two thousand pre-computed tsunami scenarios. Following any potentially tsunamigenic earthquake, warnings are issued for individual coastal zones with three different levels of threat: marine, land or no threat. The decision is based on wave amplitudes of the relevant T2 scenario within the coastal zones. Threshold amplitude values have been derived through analysis of observed impacts for recent events. Given that historical records are available for only a short time period and no observations for which a land threat would have been issued for Australia exist, it has been difficult to determine the appropriate threshold for a land threat and this is currently set at a relatively conservative value. A recent tsunami hazard assessment study for New South Wales investigated large (Mw > 8.0) earthquakes on known subduction zones and computed inundation distances using the Delft3D model nested within T2 scenarios. In this report, these modelling results are used to evaluate the threshold values for the JATWC tsunami warnings. A general conclusion is that the threshold values should not be modified on the basis of these results.
Collection(s) and Series: CAWCR technical report- No. 62
Format: Digital (Free)