Unified Interior Regions
American Samoa
The Pacific Region has nine USGS Science Centers in California, Nevada, and Hawaii. The Regional Office, headquartered in Sacramento, provides Center oversight and support, facilitates internal and external collaborations, and works to further USGS strategic science directions.
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The Pacific Region has nine USGS Science Centers in California, Nevada, and Hawaii. The Regional Office, headquartered in Sacramento, provides Center oversight and support, facilitates internal and external collaborations, and works to further USGS strategic science directions.
The Value of U.S. Coral Reefs for Risk Reduction
Summary of the report, “Rigorously valuing the role of U.S. coral reefs in coastal hazard risk reduction”
U.S. Seismic Hazard Maps – Puerto Rico and the U.S. Virgin Islands, Samoa and the Pacific Islands, and Guam and Northern Mariana Islands
Seismic hazard maps for Puerto Rico and the U.S. Virgin Islands, Samoa and the Pacific Islands, and Guam.
Thermal Imaging Camera Use: Identifying Groundwater Inputs to a Reef in American Samoa
USGS scientists used a thermal camera in American Samoa to understand the effect of land-based contaminants on an adjacent coral reef lagoon ecosystem. The infrared (IR) camera was used to capture thermal images of the lagoon to look for temperature differences to understand the distribution of freshwater entering the lagoon and the circulation of the lagoon water at various tidal levels.
21st Century High-Resolution Climate Projections for Guam and American Samoa
While home to many people and a rich diversity of unique plant and animal life, the U.S. territories of Guam and American Samoa are especially vulnerable to the effects of climate change because of their small size, geographical remoteness, and exposure to threats such as sea-level rise and increased storm surge. Developing predictions of future conditions is often the first step in helping...
USGS Scientists in Samoa and American Samoa Studying Impacts of Tsunami in 2009
On September 29, 2009, an M 8.1 earthquake in the Samoa Islands region of the South Pacific Ocean caused a tsunami that resulted in 100's of lost lives. A rapid-response team of USGS scientists traveled to the Samoa Islands in October-November 2009 to collect time-sensitive data that would have been quickly...
Projected flood extent polygons and flood depth points based on 10-, 50-, 100-, and 500-year wave-energy return periods, with and without coral reefs, for American Samoa (the islands of Tutuila, Ofu-Olosega, and Tau)
This part of the data release presents projected flooding extent polygon (flood masks) and flooding depth points (flood points) shapefiles based on wave-driven total water levels for American Samoa (the islands of Tutuila, Ofu-Olosega, and Tau). For each island there are 8 associated flood mask and flood depth shapefiles: one for each of four nearshore wave energy return periods
Projected flood extent polygons and flood depth points based on 10-, 50-, 100-, and 500-year wave-energy return periods, with and without coral reefs, for the State of Hawaii (the islands of Hawaii, Kahoolawe, Kauai, Lanai, Maui, Molokai, Niihau, and Oahu
This part of the data release presents projected flooding extent polygon (flood masks) and flooding depth points (flood points) shapefiles based on wave-driven total water levels for the State of Hawaii (the islands of Hawaii, Kahoolawe, Kauai, Lanai, Maui, Molokai, Niihau, and Oahu). For each island there are 8 associated flood mask and flood depth shapefiles: one for
Projected flood extent polygons and flood depth points based on 10-, 50-, 100-, and 500-year wave-energy return periods, with and without coral reefs, for the Territory of Puerto Rico (the islands of Culebra, Puerto Rico, and Vieques)
This part of the data release presents projected flooding extent polygon (flood masks) and flooding depth points (flood points) shapefiles based on wave-driven total water levels for the Territory of Puerto Rico (the islands of Culebra, Puerto Rico, and Vieques). For each island there are 8 associated flood mask and flood depth shapefiles: one for each four nearshore wave energy
Projected flooding extents and depths based on 10-, 50-, 100-, and 500-year wave-energy return periods, with and without coral reefs, for the States of Hawaii and Florida, the Territories of Guam, American Samoa, Puerto Rico, and the U.S. Virgin Islands,
This data release provides flooding extent polygons (flood masks) and depth values (flood points) based on wave-driven total water levels for 22 locations within the States of Hawaii and Florida, the Territories of Guam, American Samoa, Puerto Rico, and the U.S. Virgin Islands, and the Commonwealth of the Northern Mariana Islands. For each of the 22 locations there are eight ass
Pedestrian tsunami evacuation results for two tsunami-inundation zones (2009 and probable maximum tsunami (PMT)) and four travel speeds (slow walk, fast walk, slow run, and fast run) for American Samoa
This data release is comprised of a set of eight time travel map shapefiles (two tsunami inundation zones and four travel times) for use in GIS software applications and two population exposure by travel time tables (residents and nonresidences) for use in GIS software applications and other standalone spreadsheet applications. The travel time map was generated using the Pedestrian Evacu
Pedestrian evacuation times for residents on the islands of American Samoa, for 2009 and predicted maximum tsunami (PMT) inundation zones by village, modeled at four travel speeds (slow walk, fast walk, slow run, and fast run)
This dataset contains American Samoa resident count estimates as a function of travel time out of the 2009 and probable maximum tsunami (PMT) inundation zones for four different travel speeds (slow walk, fast walk, slow run, and fast run). The data are organized in a manner which permits summarizing or visualizing the data by village, tsunami-evacuation zone, and/or travel tim
Pedestrian evacuation times for businesses on the islands of American Samoa, for 2009 and predicted maximum tsunami (PMT) inundation zones by village, modeled at four travel speeds (slow walk, fast walk, slow run, and fast run)
This dataset contains American Samoa nonresidence count estimates as a function of travel time out of the 2009 and probable maximum tsunami (PMT) inundation zones for four different travel speeds (slow walk, fast walk, slow run, and fast run). The data are organized in a manner which permits summarizing or visualizing the data by business classification (church, community center
Tsunami evacuation time map for American Samoa predicted maximum tsunami (PMT) inundation zone and fast walk speed
The travel time map was generated using the Pedestrian Evacuation Analyst model (version 1.0.1 for ArcGIS 10.5) from the USGS (https://geography.wr.usgs.gov/science/vulnerability/tools.html). The travel time analysis uses ESRI's Path Distance tool to find the shortest distance across a cost surface from any point in...
Tsunami evacuation time map for American Samoa predicted maximum tsunami (PMT) inundation zone and slow walk speed
The travel time map was generated using the Pedestrian Evacuation Analyst model (version 1.0.1 for ArcGIS 10.5) from the USGS (https://geography.wr.usgs.gov/science/vulnerability/tools.html). The travel time analysis uses ESRI's Path Distance tool to find the shortest distance across a cost surface from any point in...
Tsunami evacuation time map for American Samoa predicted maximum tsunami (PMT) inundation zone and fast run speed
The travel time map was generated using the Pedestrian Evacuation Analyst model (version 1.0.1 for ArcGIS 10.5) from the USGS (https://geography.wr.usgs.gov/science/vulnerability/tools.html). The travel time analysis uses ESRI's Path Distance tool to find the shortest distance across a cost surface from any point in...
Tsunami evacuation time map for American Samoa 2009 tsunami inundation zone and fast run speed
The travel time map was generated using the Pedestrian Evacuation Analyst model (version 1.0.1 for ArcGIS 10.5) from the USGS (https://geography.wr.usgs.gov/science/vulnerability/tools.html). The travel time analysis uses ESRI's Path Distance tool to find the shortest distance across a cost surface from any point in...
Tsunami evacuation time map for American Samoa predicted maximum tsunami (PMT) inundation zone and slow run speed
The travel time map was generated using the Pedestrian Evacuation Analyst model (version 1.0.1 for ArcGIS 10.5) from the USGS (https://geography.wr.usgs.gov/science/vulnerability/tools.html). The travel time analysis uses ESRI's Path Distance tool to find the shortest distance across a cost surface from any point in...
Sea level rise in the Samoan Islands escalated by viscoelastic relaxation after the 2009 Samoa‐Tonga earthquake
The Samoan islands are an archipelago hosting a quarter million people mostly residing in three major islands, Savai'i and Upolu (Samoa), and Tutuila (American Samoa). The islands have experienced sea level rise by 2–3 mm/year during the last half century. The rate, however, has dramatically increased following the Mw 8.1 Samoa‐...
Shin-Chan Han; Sauber, Jeanne; Pollitz, Fred; Ray, RichardCoastal circulation and water-column properties in the National Park of American Samoa, February–July 2015
There is little information on the oceanography in the National Park of American Samoa (NPSA). The transport pathways for potentially harmful constituents of land-derived runoff, as well as larvae and other planktonic organisms, are driven by nearshore circulation patterns. To evaluate the processes affecting coral reef ecosystem health, it is...
Storlazzi, Curt D.; Cheriton, Olivia; Rosenberger, Kurt J.; Logan, Joshua B.; Clark, Timothy B.Effects of Climate and land use on diversity, prevalence, and seasonal transmission of avian hematozoa in American Samoa
The indigenous forest birds of American Samoa are increasingly threatened by changing patterns of rainfall and temperature that are associated with climate change as well as environmental stressors associated with agricultural and urban development, invasive species, and new introductions of avian diseases and disease vectors. Long term changes in...
Atkinson, Carter T.; Utuzurrum, Ruth B.; Seamon, Joshua O.; Schmaedick, Mark A.; Lapointe, Dennis; Apelgren, Chloe; Egan, Ariel N.; Watcher-Weatherwax, WilliamAnts of the national park of American Samoa
American Samoa makes up the eastern end of the Samoan Archipelago. On the islands of Tutuila, Taʽū and Ofu, the National Park of American Samoa (NPSA) protects about 4,000 ha of coastal, mid-slope and ridge-top forest. While the ant fauna of the Samoan Archipelago is considered relatively well documented, much of NPSA has never been surveyed for...
Banko, Paul C.; Peck, Robert W.Bacterial communities associated with healthy and Acropora white syndrome-affected corals from American Samoa
Acropora white syndrome (AWS) is characterized by rapid tissue loss revealing the white underlying skeleton and affects corals worldwide; however, reports of causal agents are conflicting. Samples were collected from healthy and diseased corals and seawater around American Samoa and bacteria associated with AWS characterized using both culture-...
Wilson, Bryan; Aeby, Greta S.; Work, Thierry M.; Bourne, David G.Coral diversity and the severity of disease outbreaks: a cross-regional comparison of Acropora white syndrome in a species-rich region (American Samoa) with a species-poor region (Northwestern Hawaiian Islands).
The dynamics of the coral disease, Acropora white syndrome (AWS), was directly compared on reefs in the species-poor region of the Northwestern Hawaiian Islands (NWHI) and the species-rich region of American Samoa (AS) with results suggesting that biodiversity, which can affect the abundance of susceptible hosts, is important in influencing the...
Aeby, G.S.; Bourne, D.G.; Wilson, B.; Work, Thierry M.Effects of fringing reefs on tsunami inundation: American Samoa
A numerical model of tsunami inundation, Delft3D, which has been validated for the 29 September 2009 tsunami in Tutuila, American Samoa, is used to better understand the impact of fringing coral reefs and embayments on tsunami wave heights, inundation distances, and velocities. The inundation model is used to explore the general conditions under...
Gelfenbaum, G.; Apotsos, A.; Stevens, A.W.; Jaffe, B.Coral and crustose coralline algae disease on the reefs of American Samoa
Surveys for lesions in corals were conducted at seven sites around Tutuila in June 2004 and January 2005. The objectives of the study were to document the distribution and prevalence of disease in the major genera of corals and crustose coralline algae, systematically describe gross and microscopic morphology of lesions in reef corals and...
Aeby, G.; Work, Thierry M.; Fenner, D.; DiDonato, EvaAreas Contributing Recharge to Wells in the Tafuna-Leone Plain, Tutuila, American Samoa
To address the concerns about the potential for contamination of drinking-water wells in the Tafuna-Leone Plain, Tutuila, American Samoa, a numerical ground-water flow model was developed and used to delineate areas contributing recharge to the wells (ACRWs). Surveys and analyses were conducted to obtain or compile certain essential hydrogeologic...
Izuka, Scot K.; Perreault, Jeff A.; Presley, Todd K.Characterizing lesions in corals from American Samoa
The study of coral disease has suffered from an absence of systematic approaches that are commonly used to determine causes of diseases in animals. There is a critical need to develop a standardized and portable nomenclature for coral lesions in the field and to incorporate more commonly available biomedical tools in coral disease surveys to...
Work, Thierry M.; Rameyer, Robert A.A new coccidian parasite, Isospora samoaensis, from the Wattled Honeyeater (Foulehaio carunculata) from American Samoa
A new species of Isospora is described from the feces of the wattled honeyeater, Foulehaio carunculata from American Samoa. Numerous oocysts of similar morphology were found in a single adult wattled honeyeater. Sporulated oocysts are ovoid, 28.9 × 26.1 (25-32 × 23-30) µm, with a smooth, colorless, bilayered wall; the inner wall is slightly...
Adamczyk, Kelly J.; McQuistion, Thomas E.; LaPointe, DennisDetection of avian malaria (Plasmodium spp.) in native land birds of American Samoa
This study documents the presence of Plasmodium spp. in landbirds of central Polynesia. Blood samples collected from eight native and introduced species from the island of Tutuila, American Samoa were evaluated for the presence of Plasmodium spp. by nested rDNA PCR, serology and/or microscopy. A total of 111/188 birds (59%) screened by nested PCR...
Jarvi, S.I.; Farias, M.E.M.; Baker, H.; Freifeld, H.B.; Baker, P.E.; Van Gelder, E.; Massey, J.G.; Atkinson, C. T.Porites and Acropora corals in American Samoa
Porites and Acropora coral species in reef flat pools in the National Park of American Samoa on Ofu, Manuʻa Islands Group, American Samoa.
Installing a thermal imaging system
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.
Divers install monitoring instruments on coral reef
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.
American Samoa Coral Reefs and Coastal Hazard Risk Reduction
Rigorously Valuing the Role of American Samoa’s Coral Reefs in Coastal Hazard Risk Reduction
Estimated Annual Benefits
Maps of American Samoa showing the distribution of the value of averted direct building damages, indirect economic activity losses, and population annually protected from flooding by coral reefs. Results at 10 m2 resolution are
...How Our Reefs Protect Us: Valuing the Benefits of U.S. Reefs (AD)
The degradation of coastal habitats, particularly coral reefs, raises risks by increasing the exposure of coastal communities to flooding hazards during storms. The protective services of these natural defenses are not assessed in the same rigorous economic terms as artificial defenses, such as seawalls, and therefore often are not considered in decision-making. Here we
Tsunami Study in American Samoa
Tsunami flow depth at Alofau, American Samoa following the tsunami that hit the island on Sept. 29, 2009.
Tsunami Study in American Samoa
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.
Tsunami Study in American Samoa
Car thrown into building in Pago Pago, American Samoa during the tsunami that struck the island on Sept. 29, 2009.
Tsunami Study in American Samoa
Vasily Titov (left) of the NOAA Pacific Marine Environmental Laboratory and USGS oceanographer Bruce Jaffe (right) standing next to a tsunami warning sign. Signs like this warn people living on the coast to go to higher ground after an earthquake.
Tsunami Study in American Samoa
Boat thrown onto fish pond in Maloata, American Samoa following the tsunami that hit the island on Sept. 29, 2009.
Tsunami Study in American Samoa
Roof moved into the ocean in Fagasa, American Samoa following the tsunami that hit the island on Sept. 29, 2009.
Tsunami Study in American Samoa
Only the foundation of a house in Fagasa, American Samoa remains after the tsunami hit on Sept. 29, 2009.
Budget Focuses on Bringing Science, Facilities, and Infrastructure into the 21st Century
USGS scientists from the Pacific Coastal and Marine Science Center and the St. Petersburg Coastal and Marine Science Center are cooperating with the National Park Service to better understand links between coastal groundwater and coral reef health on the island of Ofu in the National Park of American Samoa (NPSA).

The Samoa tsunami of September 29, 2009, was the fifth tsunami studied by U.S. Geological Survey (USGS) field teams in 15 years, and yet it presented many surprises.
Pete Gurr, a resident of American Samoa, was on his way to work when he felt an earthquake that originated 110 miles out at sea. Because of tsunami training he had received, he knew about the possibility of a deadly wave and drove down to the closest coastal village, where he warned the residents. Similarly, Tina Pule knew the earthquake was stronger than usual and told her parents to go inland.