Webinar Phil Cummins as the Banda Sea tsunami detective.

On Wednesday 29 July 2020, Phil R. Cummins of Geoscience Australia, & the Australian National University research School of Earth Science presented the webinar “Earthquakes and tsunamis caused by low-angle normal faulting in the Banda Sea, Indonesia”. The webinar was presented in English.

Phil noted that the Weber Deep and the Banda Sea subduction Arc is quite different to the standard relationship of marine trenches and subduction zones. Initial interpretations of two trenches are now replaced by a single curved and deep subduction zone, and some aspect of a shallow normal fault. Very deep earthquakes can often be more readily felt far away in Australia than nearby parts of Indonesia, suggesting the Australian plate of thick consolidated crust is more efficient transmitter of seismic waves. Also, that mud volcanoes often come and go about 100km from subduction zones. ANU with Australia Aid have undertaken a GPS Campaign in East Indonesia, wherein more data would be welcome to research this complex Banda sea region.

This webinar took on a unique role when Phil introduced us to the art of interpreting historical earthquake & tsunami, particularly the Banda events of 1629 and 1852. Historical (1852) records are combined with modern modelling software and rational, to identify the source and nature of the earthquake (shallow or deep), or the option of an undersea slump. The evidence points to a massive undersea slump. This historical detective approach also tells us more about the interpretation of the structure of the Bandar plate.