© Associated PressObsidian lava rocks at Newberry National Volcanic Monument in Oregon.
When Newberry Volcano south of Bend last erupted 1,300 years ago, gas trapped in sticky magma exploded from the caldera south of Bend, flinging pumice and ash more than 3,000 feet up into the air. As the volcanic gases settled down, flows of lava oozed out, quickly cooling into the glassy Big Obsidian Flow.
About 7,000 years ago, magma spread north from Newberry through a crack in the rock, erupting to form the Lava Butte cinder cone.
And with the magma still heating rocks under Newberry Volcano, geologists expect more eruptions to shake the area in the future.
"It's still hot under there," said Julie Donnelly-Nolan, a research geologist with the U.S. Geological Survey's Volcano Science Center in Menlo Park, Calif. "We have no reason to believe it's finished."
Because of this, the USGS is planning to add eight seismic monitoring stations next summer on Newberry Volcano, which the agency classifies as a "very high threat."
Comment: Latest recorded seismic activity around Sicily, Italy:
3 shakes and minor landslides, Feb. 18 - Stromboli
5 shakes and minor landslides, Feb. 22 - Stromboli
5 shakes and minor landslides, Feb. 28 - Stromboli
2.6 and 2.7, Mar. 4 - (Sea-quake) Porto Palo di Capo Passero, Ionio Sea
2.6 and 3.7, Mar. 9 - Messina, Sicily
2.1, April 2 - Messina, Sicily
(A 6.1 magnitude one was recorded in Greece on April 1)