Images

Summer geology intern Mindy Juergenson climbs over downed lodgepole pine trees killed in the fire of 1988 as she packs a GPS station out of the field (inset). Nine temporary stations are deployed each April/May and retrieved in October/November. The temporary stations supplement a network of permanent stations that record ground deformation data year-round.

Map of horizontal displacement vectors for Global Positioning System (GPS) stations in and around Mount St. Helens. Blue arrows show the direction and magnitude of horizontal movement, as measured at the GPS station from 2008-2014. The total horizontal displacement is indicated in millimeters (mm) and inches (in).

Some of the large ballistic blocks from the Kīlauea eruption of 1924 later became visitor attractions. Many of these blocks remain in place today as evidence of the forces unleashed at Kīlauea during the eruption of 1924.

Vectors indicate Pacific Plate motion relative to presumed fixed mantle hot spot in millimeters per year. Gray lines indicate fracture zones. Isochrons along the Emperor Seamounts chain show the age of volcanism in millions of years. Ocean floor ages from imagery available on EarthByte.

HVO seismologists use this to review automatically generated earthquake parameters (location, depth, magnitude), measure P- and S-wave arrival times, and re-compute earthquake hypocenter and magnitudes for cataloging and distribution to the public.

Although numerous intensity scales have been developed over the last several hundred years to evaluate the effects of earthquakes, the one currently used in the United States is the Modified Mercalli Intensity (MMI) Scale. It was developed in 1931 by the American seismologists Harry Wood and Frank Neumann.

Researchers map the bottom of Castle Lake, near Mount St. Helens. For three days, researchers ran a small boat over the lake surface equipped with an acoustic Doppler current profiler (ADCP). The ADCP bounces an acoustic wave off the bottom that is reflected back to a mobile receiver in the boat.

CalVO staff assembled in the Rambo Auditorium, Menlo Park, CA

Guardian Geyser and Norris Geyser Basin, Yellowstone National Park.

Scientist collects a sample of gas in a vacuum sealed glass bottle near Nymph Lake, Yellowstone National Park.

Magma forms above the subducting slab of oceanic crust and accumulates at the base of Earth's rigid crust before collecting in a storage zone 13 km (8 mi) beneath the volcano prior to eruption.

Mount Adams elevation is 3,745 m (12, 286 ft). Mount St. Helens was the smallest of five major volcanic peaks in Washington State.

Postshield eruption are the fourth stage of a Hawaiian volcano's evolution. A cap of evolved magma erupts to cover the surface of the volcano. Not all volcanoes have evidence for this phase.

Examples of seismograms of different types of earthquakes and tremor (constant ground shaking) recorded in Hawai‘i.

InSAR (Interferometric Synthetic Aperture Radar) is a technique for mapping subtle ground deformation using radar images from Earth-orbiting satellites. With its global coverage and all-weather imaging capability, InSAR has become an increasingly important technique for studying volcanoes in remote regions such as the Aleutian Islands.

White Salmon River (Washington) at USGS gauge site, 2.3 km downstream of Condit Dam, looking downstream: (a) 53 min before breaching; (b) 20 min after breaching, at discharge peak; (c) 76 min after breaching, at peak sediment concentration, with high water line evident; (d) ~2.5 h after breaching, discharge has returned to background and sediment concentration is f

Map showing global ash and aviation encounters

Ashfall will cause accelerated wear and tear on sewage pump impellers (metal pitting and thinning).

Lahar devastation after the eruption of Mount Pinatubo, Philippines.

Ash buries cars and buildings after the 1984 eruption of Rabaul, Papua New Guinea.

LOS = Line of Sight