Earthquake and Tsunami, Santa Cruz Islands

This afternoon’s under-sea earthquake in the Santa Cruz Islands has been revised to magnitude 6.9 following further analysis.

The Pacific Tsunami Warning Centre (PTWC) issued a bulletin at 4:26 this afternoon advising that a 4 cm sea-level change was detected by a wave gauge at Vanuatu at 3:39 p.m. New Zealand time, just over 2½ hours after the earthquake occurred. It is speculated that the wave may have been generated by a slower rupture in the earthquake zone.

It is still not known whether a damaging wave was generated near the earthquake epicentre. However, the waves measured 26 minutes apart near Vanuatu confirm that a tsunami threat does not exisit for other coastal areas in the Pacific, according to the PTWC. Nevertheless, some areas may experience small non-destructive sea level changes lasting up to several hours.

The US Geological Survey has reported two aftershocks of magnitude 5.4 and 4.8 at shallow depths in the Santa Cruz Islands since the main quake.

[Compiled from data supplied by the US Geological Survey and its contributing agencies, and the U.S. National Oceanic & Atmospheric Administration’s Pacific Tsunami Warning Centre.]

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