During July and August 1991, four strong earthquakes struck the northern California coast. The sequence began at 7:50 p.m., July 12 with a strong M 6.9 earthquake about 50 miles west-northwest of Crescent City in the Pacific Ocean.

The next three earthquakes occurred on August 16-17 within a space of just 24 hours. The first measured M 6.3 and struck at 3:26 p.m. on August 16 time about 62 miles WSW of Crescent City and slightly south of the initial jolt. At 12:29 p.m. the next day, August 17, 21 hours later, it was followed by a M 6.2 temblor in the Cape Mendocino region near Honeydew. The last temblor was the strongest and registered M 7.1. It struck a little less than 3 hours later and in nearly the same off shore location as the M 6.3 jolt.

The Honeydew quake was the only one centered on land and caused substantial damage in the Matole River Valley. Homes were jarred from foundations, chimneys were thrown downed, and cracked walls and broken windows were common. Landslides, rock falls, and liquefaction features were widespread, as were changes in water flows from local springs.

While the rapid sequence of events was unprecedented for the region, eight months later in 1992, another series of three M 6.0+ earthquakes shook the region and included one damaging event as large as M 7.1.

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