Images

In this view the dome is 535 feet (163 meters) high and nearly 1/4 mile (0.4 kilometers) wide, making it taller than a 44-story building (or, nearly the height of the Washington Monument) and wider than the length of four football fields. Compare with image taken August 12, 1985 from the same location with the same camera.

The U.S. Geological Survey, in conjunction with the University of Washington, maintain seismic stations at Mount St. Helens. An increase in seismicity (earthquakes) is often the first precursor to an approaching eruption.

Seismic station installation in Mount St. Helens's crater 1981 lava dome. USGS, in conjunction with the University of Washington, maintain seismic stations at Mount St. Helens. An increase in seismicity (earthquakes) is often the first precursor to an approaching eruption.

These pyroclastic-flow deposits of the climactic eruption of Mount Mazama, during which Crater Lake caldera formed, are eroded into spectacular spires at The Pinnacles on Wheeler Creek.

Pinnacles left by erosion of fumaroles that formed as layered pyroclastic flow deposit released gas and solidified into chimneys that eventually eroded, Crater Lake, Oregon.

Lahars originating from Mount St. Helens after the 1980 eruption destroyed more than 200 homes and over 185 miles (300 kilometers) of roads. Pictured here is a damaged home along the South Fork Toutle River.

Between 1980 and 1986, Mount St. Helens' dome grew in different ways. From 1980 through 1982 the dome grew in periodic extrusions of stubby lava flows, called lobes. During this time frame Mount St. Helens' lobes grew at a rate of 3 to 10 feet per hour (1-3 meters/hour).

These measurements were used to study the erosion processes and to estimate the severity of the sedimentation problem. Rod person (lower left) and instrument persons (upper right) give scale.

Photo 15 of 15: Water level in sinkhole chimney stabilized since the previous day. View to south across the sinhole.

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.

Photo 7 of 15: Cars in a sinkhole. Auto mechanic’s garage starting to collapse into sinkhole. View to south across the sinkhole.

Photo 4 of 15: House within the sinkhole. View to north across the sinkhole.

Photo 9 of 15: Community pool collapsing into sinkhole at. Pool was roughly Olympic-sized and was about half full at the time of collapse. Impressive sounds of the rebar and concrete snapping, then the rush of water. View to north across the sinkhole. (1:30 p.m)

Photo 10 of 15: Sinkhole chimney after pool collapse. View to south across the sinkholne. For a time after the pool collapse and introduction of the pool water into the sinkhole, there was a noticeable increase in slope movement, especially deeper in the sinkhole. The house and building parts broke up further and disappeared.

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 6 of 15: Sinkhole chimney at approximately 12 noon. View to south across the sinkhole.

Photo 8 of 15: Community pool prior to collapse into the sinkhole. View to north across the sinkhole. (1:30 p.m)

Photo 5 of 15: House in a sinkhole. View to east across the sinkhole.

This collection is a group of 15 images (digitized slides) showing the sinkhole that opened late in the evening of May 8, 1981 near the intersection of South Denning Drive and West Fairbanks Avenue, Winter Park, Florida, USA.