Earthquake

The earthquake was preceded by strong foreshocks on 3 and 7 November. The main shock lasted between thirty seconds and eight minutes according to various reports.^[8] A maximum Mercalli-Sieberg intensity was XI assigned in Vallenar and the surrounding region was assigned X. Shaking intensity decreased further west towards the coast, ranging from VII to IX. The location closest to the tsunami source, Caldera, was assigned VII. This suggest an inland earthquake source.^[9]

The length of the plate boundary that ruptured during the earthquake is estimated to be 390 km (242 mi).^[10]

Tsunami

The epicenter of the earthquake was well inland and the tsunami may have been caused by a submarine slide triggered by the shaking.^[11]

At Caldera the tsunami began about 15 minutes after the earthquake, with a maximum run-up height of 7 m (23 ft). At Chañaral the tsunami had three surges, the first about an hour after the earthquake, the maximum run-up height was 9 m (30 ft). Three surges were also seen at Coquimbo, the last being the most destructive with a maximum run-up of 7 m (23 ft).^[10]

The tsunami was also observed in Callao, Peru (2.4 m, 7.9 ft), California (0.2 m, 8 in 13.0 hours delay), Hawaii (2.1 m, 6.9 ft 14.5 hours), Samoa (0.9 m, 3 ft 14.1 hours), Japan (0.3 m, 1 ft), Taiwan (0.03 m, 1 in), New Zealand (0.1 m, 3.9 in), Australia (0.2 m, 7.9 in)^[12] and the Philippines (0.1 m, 3.9 in).^[8]