2026 NSHMs for GNMI and AmSam Active
The Guam and the Commonwealth of the Northern Mariana Islands (GNMI) and American Samoa (AmSam) models were last updated in 2012. The two NSHMs will be developed concurrently but will be published separately.
The updates for GNMI and AmSam will follow the timeline below, which allows for:
- 2 years of development, including evaluations of non-USGS source and ground motion models;
- Community feedback early and often, e.g., a public kick-off workshop in fall 2024, and additional workshops scheduled throughout the update process (Workshop information will be posted as soon as available); and
- 1 year for publication, including reconciliation of reviews from a peer-reviewed journal, the NSHM Steering Committee, building code and other users, and the public.
The USGS requests that the seismic hazard community bring to our attention, by June 30 of 2024, new earthquake source and ground motion data and models that could be included in the GNMI and AmSam updates.
Only published (or accepted for publication), peer-reviewed data and models will be considered. The sooner they are brought to our attention, the more likely it is we can include them in the updated NSHMs, resources permitting. Given current staffing levels, it is likely that relatively few changes will be included in the 2026 updates. Please bring the publications to our attention by emailing nshmp-support@usgs.gov. Someone will reply to confirm receipt and request additional information, if needed.
The Guam and the Commonwealth of the Northern Mariana Islands (GNMI) and American Samoa (AmSam) models were last updated in 2012. The two NSHMs will be developed concurrently but will be published separately.
The updates for GNMI and AmSam will follow the timeline below, which allows for:
- 2 years of development, including evaluations of non-USGS source and ground motion models;
- Community feedback early and often, e.g., a public kick-off workshop in fall 2024, and additional workshops scheduled throughout the update process (Workshop information will be posted as soon as available); and
- 1 year for publication, including reconciliation of reviews from a peer-reviewed journal, the NSHM Steering Committee, building code and other users, and the public.
The USGS requests that the seismic hazard community bring to our attention, by June 30 of 2024, new earthquake source and ground motion data and models that could be included in the GNMI and AmSam updates.
Only published (or accepted for publication), peer-reviewed data and models will be considered. The sooner they are brought to our attention, the more likely it is we can include them in the updated NSHMs, resources permitting. Given current staffing levels, it is likely that relatively few changes will be included in the 2026 updates. Please bring the publications to our attention by emailing nshmp-support@usgs.gov. Someone will reply to confirm receipt and request additional information, if needed.