PNG tsunami

Tsunami generated by the PNG earthquake was observed at tide gauges and ocean
bottom pressure gauges in Japan. We numerically computed the PNG tsunami and
compared the observed tsunamis with the computed ones at five tide gauges and one
ocean bottom pressure gauge (OBP) in Japan.

Location of the gauges ( pdf Figure )
Tide gauges: Naze, Tosashimizu, Kushimoto, Yaene, Chichijima
OBP: Boso

Tsunamis from two fault models, shallowly diping fault model and steeply dipping fault
model, are computed. The lengh is 40 km, the width is 15 km, and the slip is 2.9 m.
The seismic moment is 5.2 X 1019 Nm which is the same as the Harverd CMT moment.

Location of the two fault models (pdf Figure)


Chichijima, Boso, Kushimoto, Yaene, Tosa-shimizu, and Naze

The computed tsunami from the steeply dipping reverse fault model well explains
the observed tsunami. That also explains the observed tsunami much better
than the computed tsunami from the shallowly dipping fault model. This may suggest
that this earthquake was an outer-rise compressional event rather than an tipical
underthrust earthquake.

Yuichior Tanioka
Seismology and Volcanology Dept.
Meteorological Research Institute