Map of tectonic setting for NSHM27 of Guam, Northern Mariana Islands, and American Samoa
By Earthquake Hazards Program
October 2026 (approx.)
Detailed Description
This location map and inset maps of the National Seismic Hazard Model (NSHM) show areas of interest for the populated Pacific Territories of the United States. The inset maps highlight Guam and the Commonwealth of the Northern Mariana Islands (GNMI) and American Samoa (AmSam), two large regions assessed for seismic hazards in the NSHM of 2027.
The red rectangles show the extents considered for the seismic catalog; the purple rectangles are the extents for hazard calculations. Earthquake epicenters are taken from the USGS ANSS Comcat catalog and show a yellow-to-blue color ranges for shallow-to-deep locations; the Slab2 linework is shown for depths ranging from deep-to-shallow (black-purple-blue-green series). Local islands are labeled and Holocene volcanic centers (red triangles) are shown.
Sources/Usage
Public Domain.
Related
2027 Long-term National Seismic Hazard Models for the U.S. Territories of Guam, Commonwealth of the Northern Mariana Islands, and American Samoa
The U.S. Geological Survey will publish an updated National Seismic Hazard Model for the Pacific territories of Guam, Commonwealth of the Northern Mariana Islands, and American Samoa in 2027. These models were last updated in 2012.
Volcanoes in American Samoa
Volcanic activity in American Samoa is within the area of responsibility of the U.S. Geological Survey’s Hawaiian Volcano Observatory, based in Hilo on the Island of Hawai‘i. Tutuila, Ofu-Olosega and Ta‘ū are potentially active volcanoes within the United States Territory of American Samoa. All are considered low threat.
Volcanic Eruptions and Hazards in American Samoa
Hazards associated with potential volcanic activity in American Samoa include ground shaking and related hazards, local tsunami, volcanic gases, low-level localized explosions of lava, lava flows, lava ocean entry hazards, and hydrovolcanic and phreatomagmatic activity.
Introduction to the National Seismic Hazard Models
A primary responsibility of the USGS National Seismic Hazard Model (NSHM) Project is to model the ground shaking hazard from potentially damaging earthquakes for the United States and its territories. The model results can be summarized with different map views and here, we describe the maps and important features (what they show and what they don't show).
Probabilistic Forecasting of Earthquakes, Tsunamis, and Earthquake Effects in the Coastal Zone
The nation's coastlines are vulnerable to the interrelated hazards posed by earthquakes, landslides, and tsunamis. In the marine environment these events often occur in concert, and distant triggers can cause severe local effects, making the issue global in scope. As the population continues to migrate toward the coastlines, the social impacts of these hazards are expected to grow.
Tsunami and Earthquake Research
Here you will find general information on the science behind tsunami generation, computer animations of tsunamis, and summaries of past field studies.
Tsunami Field Studies
Our tsunami scientists work on international teams to study the aftermath of tsunamis around the world, to gain a better understanding the impact of potential tsunamis on coastal communities of the United States. Their work helps inform local, state, and federal coastal planning, protection, and resiliency.
Earthquake Data
Selected geophysical data for research. Products derived from these data are also available on the Products webpage.
Related
2027 Long-term National Seismic Hazard Models for the U.S. Territories of Guam, Commonwealth of the Northern Mariana Islands, and American Samoa
The U.S. Geological Survey will publish an updated National Seismic Hazard Model for the Pacific territories of Guam, Commonwealth of the Northern Mariana Islands, and American Samoa in 2027. These models were last updated in 2012.
Volcanoes in American Samoa
Volcanic activity in American Samoa is within the area of responsibility of the U.S. Geological Survey’s Hawaiian Volcano Observatory, based in Hilo on the Island of Hawai‘i. Tutuila, Ofu-Olosega and Ta‘ū are potentially active volcanoes within the United States Territory of American Samoa. All are considered low threat.
Volcanic Eruptions and Hazards in American Samoa
Hazards associated with potential volcanic activity in American Samoa include ground shaking and related hazards, local tsunami, volcanic gases, low-level localized explosions of lava, lava flows, lava ocean entry hazards, and hydrovolcanic and phreatomagmatic activity.
Introduction to the National Seismic Hazard Models
A primary responsibility of the USGS National Seismic Hazard Model (NSHM) Project is to model the ground shaking hazard from potentially damaging earthquakes for the United States and its territories. The model results can be summarized with different map views and here, we describe the maps and important features (what they show and what they don't show).
Probabilistic Forecasting of Earthquakes, Tsunamis, and Earthquake Effects in the Coastal Zone
The nation's coastlines are vulnerable to the interrelated hazards posed by earthquakes, landslides, and tsunamis. In the marine environment these events often occur in concert, and distant triggers can cause severe local effects, making the issue global in scope. As the population continues to migrate toward the coastlines, the social impacts of these hazards are expected to grow.
Tsunami and Earthquake Research
Here you will find general information on the science behind tsunami generation, computer animations of tsunamis, and summaries of past field studies.
Tsunami Field Studies
Our tsunami scientists work on international teams to study the aftermath of tsunamis around the world, to gain a better understanding the impact of potential tsunamis on coastal communities of the United States. Their work helps inform local, state, and federal coastal planning, protection, and resiliency.
Earthquake Data
Selected geophysical data for research. Products derived from these data are also available on the Products webpage.