Do these earthquakes mean that an even larger earthquake is coming?
Probably not. The slowly decaying aftershock sequence suggests that the stresses that produced the large earthquakes have been mostly relieved, the aftershocks are doing final cleanup, and the conditions are not those for setting up another major quake in that area and depth.
If these quakes had been foreshocks to a larger earthquake to come, they probably would be building, rather than decaying, in frequency and intensity.
But there are more earthquakes coming, and some will be stronger. The island of Hawai'i has earthquakes all the time. The strong earthquakes of October 15, 2006, won't be the last damaging earthquakes that will ever shake our island. We live in a seismically and volcanically active place.
The most significant aspect of the earthquakes on October 15 was that they ended the longest period of Big Island history without any M6.0 earthquakes since 1823. In other words, the past 17 years since the M6.2 in 1989 was the longest period without any M6 or larger earthquakes in more than 180 years.
Residents have gotten used to a seismically quieter life; this earthquake is actually reminding us that the last 17 years of seismic quiet was the anomaly, not the earthquakes that ended the quiet period.
Large Hawaiian earthquakes and rupture zones (Klein and others, 2001).
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Updated: 31 October 2006 (pnf)