An earthquake registering 6.7 Mw occurred off the northwestern coast of the island of Hawaii.

The 2006 Kīholo Bay earthquake occurred on October 15 at 07:07:49 local time with a magnitude of 6.7 and a maximum Mercalli intensity of VIII (Severe). The shock was centered 21 kilometers (13 mi) southwest of Puakō and 21 km (13 mi) north of Kailua-Kona, Hawaiʻi, just offshore of the Kona Airport, at a depth of 38.2 km (23.7 mi). It produced several aftershocks, including one that measured a magnitude of 6.1 seven minutes after the main shock. The Pacific Tsunami Warning Center measured a nondestructive tsunami of 4 in (100 mm) on the coast of the Big Island.

The moment magnitude scale is a measure of an earthquake's magnitude based on its seismic moment. M_w  was defined in a 1979 paper by Thomas C. Hanks and Hiroo Kanamori. Similar to the local magnitude/Richter scale (M_L ) defined by Charles Francis Richter in 1935, it uses a logarithmic scale; small earthquakes have approximately the same magnitudes on both scales. Despite the difference, news media often use the term "Richter scale" when referring to the moment magnitude scale.

Hawaiʻi, sometimes written Hawaii, is the largest island in the United States, located in the state of Hawaii, the southernmost state in the union. It is the southeasternmost of the Hawaiian Islands, a chain of volcanic islands in the North Pacific Ocean. With an area of 4,028 square miles (10,430 km²), it has 63% of the Hawaiian archipelago's combined landmass. However, it has only 13% of the archipelago's population. The island of Hawaiʻi is the third largest island in Polynesia, behind the North and South Islands of New Zealand.