and deposited ash in 11 U.S. states. The eruption killed 57 people and thousands of animals and caused more than a billion U.S. dollars in damage. Over 1.3 km3 of tephra was ejected during this eruption. 1914–1917 eruptions of Lassen Peak On May 22, 1915, an explosive eruption at Lassen Peak devastated nearby areas and rained volcanic ash as far away as to the east. A huge column of volcanic ash and gas rose more than into the air and was visible from as far away as Eureka, California, to the west. A pyroclastic flow swept down the side of the volcano, devastating a area. This explosion was the most powerful in a 1914–1917 series of eruptions at Lassen Peak. 2350 BP (400 BC) eruption of the Mount Meager massif The Mount Meager massif produced the most recent major eruption in Canada, sending ash as far away as Alberta. The eruption sent an ash column approximately high into the stratosphere. This activity produced a diverse sequence of volcanic deposits, well exposed in the bluffs along the Lillooet River, which is defined as the Pebble Creek Formation. The eruption was episodic, occurring from a vent on the north-east side of Plinth Peak. An unusual, thick apron of welded vitrophyric breccia may represent the explosive collapse of an early lava dome, depositing ash several meters (a dozen or so feet) in thickness near the vent area. The volume of magma erupted in this event is equal to 2 km3. 7700 BP (5783 BC) eruption of Mount Mazama The 7,700 BP eruption of Mount Mazama was a large catastrophic eruption in the U.S. state of Oregon. It began with a large eruption column with pumice and ash that erupted from a single vent. The eruption was so great that most of Mount Mazama collapsed to form a caldera and subsequent smaller eruptions occurred as water began to fill in the caldera to form Crater Lake. Volcanic ash from the eruption was carried across most of the Pacific Northwest as well as parts of western Canada. 13100 BP (11,150 BC) eruptions of Glacier Peak About 13,000 years ago, Glacier Peak generated an unusually strong sequence of eruptions depositing volcanic ash as far away as Wyoming. These eruptions were some of the largest to occur in Washington state in the last 15,000 years, with one of them being a staggering 5 times larger than the