16th September, 2015 Tsunami caused by the Earthquake in Chile – Earthquake Research Institute, the University of Tokyo

Website launched:2015/09/17
Last updated:2015/09/18

16th September, 2015 at 7:54PM(Chile time), a magnitude 8.3 Earthquake struck Chile. (cited from USGS)

Tsunami caused by this earthquake might be reaching Japan.

(Earthquake and Volcano Information Center: Aditya Gusman/Kenji Satake)

Earthquake source model

We estimated a single fault model based on W phase solution. The strike, dip, and rake angles are from the focal mechanism. The fault length, width and slip amount are estimated from the W phase seismic moment.

Strike = 356°

Dip = 28°

Rake = 79°

Centroid depth = 25 km

Seismic moment = 2.13E+21 N.m (Mw 8.2)

Fault length = 160 km

Fault width = 80 km

Slip amount = 4.5 m

Sea surface deformation of the 2015 Chile earthquake generated from a single fault model based (black rectangle) on W phase centroid moment tensor solution. Yellow star indicates the centroid location beach ball indicates the focal mechanism. — Sea surface deformation of the 2015 Chile earthquake generated from a single fault model (black rectangle) based on W phase centroid moment tensor solution. Yellow star indicates the centroid location and beach ball indicates the focal mechanism.

The plots of observed vs simulated tsunami waveforms at TM1 and TM2

(Center for Geophysical Observation and Instrumentation: Shinichi Sakai)

Change in sea level observed by the Ocean Bottom Seismograph System set off the coast of Kamaishi

The hydraulic gauge of TM1( located on the trench side) is set approx. 76km from land and at 1600m depth. TM2 (located on the land side) is set approx. 47km from land and is at 1000m below sea surface.

horizontal axis: Time (18th Sept) vertical axis: Height of the sea surface in cm — horizontal axis: Time (18th Sept)
vertical axis: Height of the sea surface in cm

(Earthquake and Volcano Information Center: Kenji Satake)

Numbers indicate the time (hours) since earthquake occurence (around 8AM this morning-Japan time)

Maximum tsunami height distribution (predicted)

Predicted waveforms at TM1 and TM2

Horizontal axis indicate for the time (hours) since earthquake occurence (at 7:54 AM this morning-Japan time)

A few cm (about 1cm for the first wave）height tsunami is expected to reach Japan from 5:30AM tomorrow morning.

D32402 — Here are a comparison of waveforms at DART 32402 and plots of simulated tsunami at TM1 and TM2 (black is data and red is simulation)