The Inyo Craters eruption about 600 years ago, Long Valley caldera, California

The last activity of the Inyo Crater occured at South Deadman, Obsidian Flow, and Glass Creek vents, producing spectacular explosion craters, deposits of pyroclastic flows and ashfall.
Ash fall from the initial phreatic and phzreatomagmatic phase at South Deadman vents is found more than 20 km NE and covered an area of 80 km2. The second phase from the Obsidian Flow vent saw the formation of a lava dome reaching a volume of 170,000 m3. A stong explosive eruption also ejected pumice and ash high into the air. The deposit is found more than 25 km to the NE and covers 140 km2.
The largest and final magmatic explosive activity of the Inyo eruptions occurred at the Glass Creek vent, located between Obsidian and South Deadman vents. Wind carried tephra from the eruption column toward the south-southwest. Near the vent, the resulting deposit is more than 8 m thick. At a distance of 12 km from the vent, the deposit is more than 50 cm thick. It covers ca. 9000 km2 and is found up to 190 km away.
Phreatic eruptions occurred again at the end of the eruption. 3 explosions south of Deadman flow formed Inyo Craters.
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Source: USGS