Newberry Volcano is the largest volcano in the Cascades volcanic arc and covers an area the size of Rhode Island (about 3100 km2 or 1200 mi2). Unlike familiar cone-shaped Cascades volcanoes, Newberry was built into the shape of a broad shield by repeated eruptions over the past 400,000 years. Throughout its eruptive history, Newberry has produced ash and tephra, pyroclastic flows, and lava flows that range in composition from basalt to rhyolite. About 75,000 years ago a major explosive eruption and collapse event created a large volcanic depression at its summit that now hosts two caldera lakes. Newberry last erupted about 1,300 years ago, and present-day hot springs and geologically young lava flows indicate that it is still an active volcano.
Newberry is one of the largest Quaternary volcanoes in the United States, with a caldera that spans 6 to 8 km across. The center of the volcano is located about 35 km SE of Bend, OR.
Construction of the volcano began about 400,000 years ago; since that time it has erupted in a variety of styles ranging from basalt flows to far-reaching explosions of ash. A major explosion and collapse event about 75,000 years ago created Newberry's summit caldera. The caldera contains multiple hot springs, indicating that it is still hydrothermally active. These hot springs and multiple youthful lava flows indicate that the volcano could reawaken at any time.
One detail about jargon - triggered earthquakes are pushed over the edge by a geophysical disturbance but the causative stress was already in the ground, induced earthquakes are powered by the disturbance, in other words, for induced events, the stress that powered the event was not present until the disturbance.
Very good question indeed.
Why if all the drilling activity is on the left side of the lakes, are we seeing some quakes on the, umm, right?
Well apparently most of it is being caused because of the drilling project (geothermal) to the west of it, and the seismicity was anticipated. What I want to know then is why we are also getting quakes well east of the drilling, and near the crater then, too. I suppose they anticipated that too, eh?
There are a couple things to consider. First, we put in a new network there so that we can better locate earthquakes (triggered and natural). So the threshold has come way down in the last year and some of what you are seeing could be earthquakes that are natural. Second, the purpose of their project is to create permeability, which means they want to create earthquakes. No energy source comes without its tradeoffs. Geothermal energy is pretty low impact compared with many... and their injection fluid is H2O... unlike some other drilling protocols.