Volcano Live

Earthquakes are able to disturb volcanic systems. In 1992 an earthquake in Landers, Southern California triggered deformation in the active Long Valley caldera. An article in Nature (29th October 1998 p 888-90) discussed this phenomenon. The conclusion was that large earthquakes (> magnitude 7) were able to trigger volcanic eruptions within a radius of 750 km.

Volcanic Eruptions Triggered by Earthquakes

Nyiragongo (2002)
On 4 January 2002, an earthquake measuring 4.8 on the Richter scale struck the area near Nyiragongo volcano. Two weeks later Nyiragongo erupted resulting in half a million evacuees!

Yasur Volcano (2002)
On January 3, 2002 a magnitude 7.3 earthquake hit Vanuatu. Two days later Yasur volcano increased its eruptive activity. On January 16, 2002 the Vanuatu Red Cross was preparing evacuation plans for part of the island of Tanna due to the contaminated water supplies and increased ash fall.

California (1992)
Southern California's largest earthquake since 1952, M 7.5 occurred on 28 June 1992. It appeared to trigger seismicity at several volcanic centers in California.
The earthquake was centered roughly 200 km E of Los Angeles.  Marked increases in microseismicity were observed at Lassen Peak, Medicine Lake caldera, and the Geysers. No earthquakes were observed at Shasta, but the lack of operating stations on the volcano limited the capability to observe small events.  Within eight minutes of the major earthquake's origin time, seismic activity within Long Valley caldera (400 km NNW of the epicenter) increased abruptly.  Of the >260 events located by the RTP system during the next three days, three were of M 3 or greater.

Ulawun Volcano (1983)
Volcano-seismic activity increased suddenly with the appearance of continuous harmonic tremor at 0200 on 24 December, less than 2 days after two strong regional earthquakes (ML 6.4 and 6.5, MM IV-V) about 150 km ESE of Ulawun Volcano (Papua New Guinea) at 0932 and 1102 on 22 December 1983.

Effects of volcano-tectonic earthquakes on Volcanoes