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Photo 11 of 15: Intersection of South Denning Drive and West Comstock Ave. Sinkhole is edging close to Denning Drive. One block of Comstock Ave was swallowed. View to south on Denning Drive adjacent to the sinkhole.

Photo 12 of 15: Water level has risen and is now apparent in sinkhole since pool collapse and house swallowed. View to south across the sinkhole. The rising water level is likely a result of the debris plugging the conduit into the Floridan aquifer. Water level is rising to assume a position more consistent with that of the surficial aquifer. (3 p.m.)

Photo 13 of 15: Water level in sinkhole chimney continued to rise. View to east across the sinkhole. (6 p.m.)

Photo 14 of 15: Remnants of community pool in sinkhole. View to east across the sinkhole.

U.S. Army Corps of Engineers preformed dredging projects on the Toutle, Cowlitz, and Columbia Rivers and by 1987 enough material had been removed to build a 12 lane highway, one-foot thick from New York, NY to San Francisco, CA.

Aerial view of Arizona's Meteor Crater, a 180 meter deep, 1.2 kilometer diameter bowl-shaped impact crater in Northern Arizona. The crater formed approximately 50,000 years ago by the impact of a 100,000-ton iron-nickel meteorite that was approximately 30 meters in diameter and struck at an approximate speed of 12-20 km/sec.

Mesquite Flat Sand Dunes, Death Valley National Park, May 1980.

Measuring tilt in Timberline parking lot in early April 1980 during lightly falling snow.

Small phreatic eruption of Mount St. Helens in the spring of 1980, before the May 18, 1980 blast.

South Fork of the Ogden River streamgage shelter in the fall of 1980. This streamgage has been monitoring water levels and flow since March 21, 1921, making it one of 25 centennial gauges in Utah. 

Left: Horseshoe-shaped crater of Mount St. Helens in 1980, formed by a landslide that removed the top of the volcano. The crater is about 2 km (1.2 mi) wide and the floor is about 600 m (1,970 ft) below the crater rim. Right: Halema‘uma‘u nestled in the summit crater of Kīlauea Volcano on August 1, the day before the last collapse event.

USGS scientist Jim Cloern with the R/V Polaris, 1980s.

This October dome was taller than a nine-story building and wider than the length of three football fields. This dome was not the first dome to grow in the crater. In June and August 1980, two domes formed, only to be blasted away by the explosive events of July 22 and October 16.

Nearly 135 miles (220 kilometers) of river channels surrounding the volcano were affected by the lahars of May 18, 1980. A mudline left behind on trees shows depths reached by the mud.

Many smaller animals, such as gophers, mice, frogs, fish, and insects were hibernating below ground or under water on May 18, 1980, and they survived the blast. Larger animals such as bear (whose tracks are shown here), elk, deer, and coyotes have been moving back into the area as their food supplies increase.

This lake was once surrounded by lush forest and is within the area devastated by the directed blast, covered by ash and tephra, then inundated by pyroclastic flows. Remnants of the forest float on the surface of the lake. Mount Rainier (4,392 m or 14,410 ft) is in the distance. The view is from the south.

The direction of the blast, shown here from left to right, is apparent in the alignment of the downed trees. Over four billion board feet of usable timber, enough to build 150,000 homes, was damaged or destroyed.

Muddy River bridge crossing destruction from May 18, 1980 Mount St. Helens lahars.

After the May 18, 1980 eruption, Mount St. Helens' elevation was only 8,364 feet (2,550 meters) and the volcano had a one-mile-wide (1.5 kilometers) and approximately 600 m (2000 ft) deep horseshoe-shaped crater. View here is from the northwest.

Mount St. Helens soon after the May 18, 1980 eruption, as viewed from Johnston's Ridge.

Mount St. Helens soon after the May 18, 1980 eruption, as viewed from Johnston's Ridge.