Answer:
Yellowstone, 640K years ago (VEI 8)
Explanation:
The entire Yellowstone National Park is an active volcano rumbling beneath visitors' feet. And it has erupted with magnificent strength: Three magnitude-8 eruptions rocked the area as far back as 2.1 million years ago, again 1.2 million years ago and most recently 640,000 years ago. "Together, the three catastrophic eruptions expelled enough ash and lava to fill the Grand Canyon," according to the U.S. Geological Survey. In fact, scientists discovered a humongous blob of magma stored beneath Yellowstone, a blob that if released could fill the Grand Canyon 11 times over, the researchers reported on April 23, 2013, in the journal Science.
The latest of the trio of supervolcano eruptions created the park's huge crater, measuring 30 by 45 miles across (48 by 72 kilometers).
idk if this is what you mean but thought it might help!