Images

A cliff on Ta‘ū island in American Samoa, exposing part of a tuff cone that was created from phreatomagmatic processes through the interaction of lava with shallow seawater. This part of the tuff cone contains mostly sand-sized material that hosts larger blocks and bombs that are up to several feet (one meter) in diameter.

The base of a tuff cone near the coast of Ta‘ū Island in American Samoa. Tuff cones are created from phreatomagmatic processes through the interaction of lava with shallow seawater. This part of the tuff cone contains mostly sand size material that hosts larger blocks and bombs that are up to several feet (one meter) in diameter.

A view of the summit region of Ta‘ū island, in the Manu‘a island group of American Samoa. Ta‘ū island is the exposed top of a volcano that formed as a result of volcanic activity at the Samoa hotspot. Most of the volcano is under the ocean surface.

A broadband seismometer being installed on Ta‘ū island near Fiti‘uta on August 23, 2022, by the USGS Hawaiian Volcano Observatory, NOAA National Weather Service, and with help from the American Samoan government and local residents of Ta‘ū island.

A broadband seismometer was installed on Ta‘ū island on August 22, 2022, by the USGS Hawaiian Volcano Observatory and NOAA National Weather Service team. This is one of two broadband seismometers that have been placed on Ta‘ū island to help detect earthquakes that started to be felt in the region starting in late July. USGS photo by D. Downs.

An afternoon view of the tuff cone near Faleāsao village located in northwest Ta‘ū island, with the islands of Ofu and Olosega visible in the distance. This tuff cone, which is thousands of years old, formed when hot magma interacted with either shallow groundwater or sea water. There are several tuff cones located within the northwest corner of Ta‘ū island.

A Raspberry Shake microseismometer was installed on Ta‘ū island, American Samoa, on August 19, 2022, by the USGS Hawaiian Volcano Observatory and NOAA National Weather Service team. This is one of several microseismometers that have been placed within the Manu‘a islands to help detect earthquakes in the region that started to be felt in late July. USGS photo by D.

Earthquakes in oceanic environments can generate pressure waves that travel long distances within the ocean itself. Much like seismographs record ground shaking, this energy is recorded by submerged hydrophones measuring pressure changes in water.

Thermal infrared image of two USGS researchers standing on the coastline and looking out (up on the image) over a coastal groundwater plume that is non-visible to the naked eye but can be observed in this thermal image due to the temperature differences between the cooler (blue) groundwater and warmer (pink) ocean water over the coral reefs.

Porites and Acropora coral species in reef flat pools in the National Park of American Samoa on Ofu, Manuʻa Islands Group, American Samoa.

USGS scientists install a thermal imaging system in the National Park of American Samoa off the south shore of Ofu, Manua. The system detects temperature variations, like a colder freshwater plume that emanates from the shore.

Dive operations with National Park Service and the National Park of American Samoa installing tide, wave, temperature, and salinity sensors on the fore reef in NPSA off the south shore of Ofu, Manuʻa.

Rigorously Valuing the Role of American Samoa’s Coral Reefs in Coastal Hazard Risk Reduction

Estimated Annual Benefits

Aluminum roofs and debris transported behind the village of Tula on the east shore of American Samoa following the Tsunami that hit the island on Sept. 29, 2009. The tsunami runup was 16-26 feet in Tula.

Tsunami flow depth indicator at Fagasa, American Samoa following the tsunami that hit the island on Sept. 29, 2009. Vegetation is brown where it was submerged by the tsunami and green above.

Car thrown into building in Pago Pago, American Samoa during the tsunami that struck the island on Sept. 29, 2009.

Boat thrown onto fish pond in Maloata, American Samoa following the tsunami that hit the island on Sept. 29, 2009.

Tsunami sand deposit at Alao, American Samoa following the tsunami on Sept. 29, 2009. Light colored sand deposited during the tsunami overlies darker soil that was there before the tsunami.

Tsunami flow depth at Alofau, American Samoa following the tsunami that hit the island on Sept. 29, 2009.

Only the foundation of a house in Fagasa, American Samoa remains after the tsunami hit on Sept. 29, 2009.

Cars damaged by the tsunami in Fagasa, American Samoa. The tsunami hit the island on Sept. 29, 2009.