Images

This photo, taken from an airplane, shows Aunu‘u Island from the south looking north; Tutuila Island is visible on the left. Aunu‘u Island is a tuff cone less than 1 mile southeast of Tutuila Island and is considered part of Tutuila volcano. A tuff cone can form when magma and water interact at shallow depths, causing localized explosions.

This photo, taken from an airplane, shows Ofu-Olosega from the southeast looking northwest. Olosega Island is in the right foreground, while Ofu Island is in the middle left background. Ocean waves are breaking at some distance from shore where there is a coral reef. According to the 2020 US Census, less than 300 people live on Ofu-Olosega. USGS photo by N.

Two USGS scientists service a seismic station on Tutuila island in American Samoa. The Hawaiian Volcano Observatory uses this site and three others to monitor volcanic activity in American Samoa. These stations are also used by the NOAA Pacific Tsunami Warning Center and the USGS National Earthquake Information Center. USGS photo by N. Deligne.

This photo, taken from an airplane, shows the eastern Ta‘ū Island coastline south of Fitiuta village; the view is from the north looking south. The black rock on the coast are lava flows of an unknown age. USGS photo by N. Deligne.

This photo, taken from an airplane, shows Ofu Island from the south looking north. Nuʻutele Island is visible to the left (west) of Ofu Island. The tallest point of Ofu Island is the peak of Tumutumu Mountain at 1,611 feet (491 meters). The westernmost edge of Olosega Island is visible to the right of Ofu Island; the two islands are connected by the Asaga bridge.

This panorama photo shows the heavily vegetated Judds Crater from the north looking south on eastern Ta‘ū Island in American Samoa.

This photo, taken from a boat looking to the northwest, shows Olosega Island on the right and Ofu Island on the left in the distance. Together, they make up the top of Ofu-Olosega volcano, most of which is underwater. USGS photo by N. Deligne.

A USGS Hawaiian Volcano Observatory seismologist services the FAGA seismic station on eastern Taʻū Island, American Samoa. This station is part of the volcano monitoring network of American Samoa, and is also used by the USGS National Earthquake Information Center (NEIC) and by the NOAA Pacific Tsunami Warning Center (PTWC). USGS photo by N. Deligne.

This photo, taken from a boat, shows the northwest side of Nuʻutele Island, off the west coast of Ofu Island in the Manuʻa Islands, American Samoa. Nuʻutele Island, which may be known by other names locally, is an eroded tuff cone of Ofu-Olosega volcano. A tuff cone can form when magma and water interact at shallow depths, causing localized explosions.

A unique cartographic layout highlights the global scope of the US and the associated reach of version 2 of the Cooperative National Geologic Map, which now depicts the history and distribution of geologic units and structures across all states and most territories.

This photo, taken from a boat, shows the eastern side of Olosega Island in the Manuʻa Islands of American Samoa. This volcanic island is part of Ofu-Olosega volcano, which is estimated to be 440,000 years old. USGS photo by N. Deligne.

Panorama of Faleāsao village harbor on northwest Ta‘ū island, looking primarily north. This harbor is situated within a tuff cone that 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. USGS photo by N. Deligne.

This photo, taken from a boat looking south, shows Olosega Island to the left, Ofu Island to the right, and the Asaga bridge connecting the two islands. The Asaga bridge was built in 1970; this single-lane bridge connects the two islands that form Ofu-Olosega volcano. USGS photo by N. Deligne.

This reference map depicts the volcanoes of the Manuʻa Islands, American Samoa, which are monitored by the USGS Hawaiian Volcano Observatory.

Broadband seismometer site on eastern Taʻū, American Samoa, before (inset) and after a work party cleared rapidly growing vegetation which had covered the solar panels along with the boulders to the right of the main photo. Due to lack of power from the solar panels being unable to charge during the day, the station was offline for many months.

This photo, taken from a boat, shows Olosega Island on the left, and Ofu Island further away on the right, in the Manuʻs Islands of American Samoa. These islands, connected by a one-lane bridge (out of sight), are the top of Ofu-Olosega volcano. USGS photo by N. Deligne.

This photo shows part of the western Ofu coastline and several small islands west of Ofu Island, American Samoa. These islands are considered part of Ofu-Olosega volcano in the Manuʻa Islands.

USGS Hawaiian Volcano Observatory scientists and NOAA National Weather Service Weather Service Office Pago Pago meteorologists travelled by boat between the Manuʻa Islands, American Samoa, during an outreach and monitoring network maintenance trip in early September 2025. This view is from the boat looking south towards the north side of Ofu Island.

Photo of the USGS Global Positioning System (GPS) monitoring station on western Ta‘ū Island in the Manuʻa Islands of American Samoa. The station consists of a GPS unit, which can measure very slight movements of the ground, placed on a tripod that is leveled and centered over a benchmark.

USGS Hawaiian Volcano Observatory scientists took this photo of Aunu‘u Island while on a flight from Tutuila to Ofu Island in American Samoa on September 2, 2025. The view is from the south looking north. Aunu‘u Island is a tuff cone less than 1 mile southeast of Tutuila Island and is considered part of Tutuila volcano.

USGS Hawaiian Volcano Observatory chief field engineer Kevan Kamibayashi conducts maintenance on a volcano-monitoring station located in American Samoa. USGS photo by J. Chang.