Images

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.

Rejuvenated stage volcanism occurs after the volcano has moved away from the mantle hot spot. Eruptions occur in sporadic locations and may be interspersed with long periods of erosion.

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

Michael Poland, Scientist-in-Charge of the Yellowstone Volcano Observatory.

An American exchange participant views the former hospital in Amero where the entire first floor was buried by lahars from Nevado del Ruiz (the second floor is visible).

U.S. and Chilean scientists prepare for a research flight during the 2008 VDAP eruption response at Chaitén.

View of Mount Baker from the west. Summit area draped with aerial imagery from National Agriculture Imagery Program (NAIP) collected in September 2015. Digital topography from High-resolution digital elevation dataset for Mount Baker and vicinity, Washington, based on lidar surveys of 2015: U.S.

Table of ash fall severities based on accumulated thickness.

Collapsed roofs after severe ashfall from Galunggung Volcano, West Java, Indonesia.

Surveyor Frank Dodge's 1894 cross-section of Halema‘uma‘u overlaid on his 1892 cross-section. The 1892 lava lake was measured at 73 m (240 ft) below the rim of Halema‘uma‘u pit and by early-1894, the lava lake had filled the pit and frequently overflowed onto the caldera floor.

Photograph taken on March 20, 1894 looking up at the Halemaʻumaʻu lava lake perched atop a low dome on the floor of Kaluapele (Kīlauea caldera).

The painting by Jules Tavernier, depicting the 1880-81 lava flow from Mauna Loa as it enters a stream near Hilo, Hawaii on July 20, 1881, provided courtesy of the National Park Service, Hawaii Volcanoes National Park (catalog number HAVO 806).

Strong shaking during the 1868 Hayward Fault earthquake caused the second story of the Alameda County Courthouse in San Leandro to collapse (photo courtesy of the Bancroft Library, University of California). The inset photo shows the courthouse before the quake

Pedernales River at Hamilton Pool Crossing after September 1952 flood. Trees destroyed by flood of September 11, 1952.  Discharge of Pedernales River near Spicewood, TX (USGS station 08154000) was 452,000 cfs.

Full view of the ground with the San Andreas fault running through the middle of the image. A 30 foot steam offset from the 1857 earthquake can be seen near the right edge of the image.

Sign above bathroom at Horseshoe Lake announcing CO2 hazard. Notice the ventilation in the bathroom.

Shipwrecks and other artificial structures increase the potential for large invasions of unwanted species into coral reefs, even relatively pristine ones. In this picture, a shipwreck in the remote Palmyra Atoll in the central Pacific Ocean resulted in the dense colonization of an invasive coral-like species called Rhodactis howesii, pictured here.

Shipwrecks and other artificial structures increase the potential for large invasions of unwanted species into coral reefs, even relatively pristine ones. In this picture, a shipwreck in the remote Palmyra Atoll in the central Pacific Ocean resulted in the dense colonization of an invasive coral-like species called Rhodactis howesii, pictured here.

The volcanoes from closest to farthest are Mt. Washington, Three Fingered Jack, Mt. Jefferson. This picture is taken from Middle Sister looking north in the Cascade Range, Three Sisters Wilderness Area, Deschutes National Forest, Oregon.

Floodwater at Wild Rice River. Photo taken from bridge at 174th Ave and 124th St southwest of Horace, ND.

Home surrounded by floodwater from Wild Rice River. Photo taken from bridge at 174th Ave and 124th St southwest of Horace, ND.