In 1924, when similar conditions occurred at Kilauea on the Big Island, there were more than 50 distinct explosions like the one Thursday over a period of more than two weeks, she said.
PHOTOS: Take a look at some of the most arresting images from Kilauea volcano eruption Kilauea is also a reminder that there are volcanoes in the Western U.S. and in California.
"Not your average wake-up call at the Kilauea Volcano summit", the U.S. Geological Survey said of the 4:17 a.m. blast that lasted several minutes. One of the latest shots is a view of a "moonscape" with a massive rock in the middle. The USGS estimates the rock was about 2 feet (0.6 meters) across before it broke up on impact.
Recent explosions have been steam-driven, occurring when water beneath the ground or on the surface is heated by magma, lava, hot rocks or new volcanic deposits, the USGS says.More news: OU's Maggie Nichols, other assault survivors to receive Arthur Ashe Courage Award
Such observatories already exist in Hawaii, Alaska, California, Wyoming and Washington, but the legislation would upgrade and integrate the systems, expand the number of volcanoes that are monitored and create a grant program that would support research into emergency technologies.
An ash plume Wednesday rose roughly 12,000 feet into the air, and on Tuesday, the USGS issued a red alert, which means a major eruption is imminent or underway and ash could affect air traffic.
After an eruption from the Kilauea volcano's summit shot ash and smoke 30,000 feet into the air on Thursday, officials handed out nearly 18,000 masks to help residents deal with the fallout.
The crater spewing ash sits within Hawaii Volcanoes National Park, which has been closed since May 11 as a safety precaution over risks of a violent eruption.More news: Trump asked me twice the difference between HIV and HPV - Bill Gates
Officials on Hawaii's Big Island will be handing out free masks to protect people from breathing volcanic ash. The prohibition applies to a 5-mile radius around the crater. More than 1,000 people have been evacuated so far. Hoyt explained the biggest concern though is the toxic sulfur dioxide that's seeping from the fissures caused by the volcano. Residents say the haze across the area is so thick it resembles fog, with visibility extremely low in some areas.
Michelle Coombes said the eruption had temporarily relieved some pressure in the volcano but there may be more, larger powerful events.
As the lava level shrank, "there is nothing holding those walls up", Krippner said.
So far, about 40 homes and other buildings have been destroyed by the red-hot lava that has been flowing from the volcano since early this month.More news: Kim Kardashian shares CUTEST pic of North and Saint
Officials have said they didn't expect the explosion to be deadly as long as people remained out of park.