Earthquake Hazards

NSHMP Workshops

Please read the disclaimer at the bottom of the page about the content of presentations linked from here.

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Upcoming Workshops

May 25, 2021 - 2023 Update to the Alaska NSHM - RSVP - I want to attend

You are invited to participate in a virtual workshop on the update to the Alaska National Seismic Hazard Model (NSHM). The Alaska NSHM was last updated in 2007 (USGS Open-File Report 2007-1043). This update is part of a 50-state update for U.S. NSHMs to be released in 2023. At the workshop, we will present our plans for updating both source and ground motion models. Specifically, we are considering updates to (1) crustal finite fault and gridded seismicity sources, scaling relations, and rate models (geologic and geodetic), (2) subduction interface and intraslab sources, scaling relations, and rate and recurrence models, and (3) ground motion models for all tectonic settings (e.g., NGA-West2, NGA-Subduction) giving consideration to site, basin, and other localized effects.

Please save the date of Tuesday, May 25, 2021 for this workshop. If you have interest in attending the workshop, please RSVP using the link above. A detailed agenda will be sent in March. Please contact Peter Powers or Allison Shumway for more information.

June 28-30, 2021 - NSHM User-Needs Workshop - Save the Date

The USGS is hosting a remote user-needs workshop for the upcoming 2023 National Seismic Hazard Model (NSHM). Unlike previous NSHM user-needs workshops, this one will primarily focus on needs that affect/change the scientific development of the NSHM. For example, user needs for longer-period ground motions have led to incorporation of basin effects in the NSHM. 

We are finalizing the agenda and other details, which we will post soon. In the meantime, please save the date, and if you have any questions about the user-needs workshop, please reach out to Ben Mason or Nico Luco.

July 9, 2021 - NGA-Subduction Workshop - Save the Date

The USGS is hosting a virtual workshop on the use of NGA-Subduction Ground Motion Models (GMMs) in the 2023 National Seismic Hazard Model (NSHM). We have set the date for Friday July 9 and invite you to join us. We are still finalizing the agenda, but we anticipate a morning session and an afternoon session, tentatively 9am-11am and 12pm-3pm Pacific Time. The morning session will focus on the NGA-Subduction models, the afternoon session will focus on the use of these models and other subduction GMMs in the USGS NSHM, and both sessions include discussions and interactions between the NGA modelers and USGS scientists.

The final agenda and sign-up sheet for attending this workshop will be posted on this webpage soon. If you have any questions about this workshop, please reach out to Sanaz Rezaeian or others on our planning committee. Planning Committee: Sanaz Rezaeian, Peter Powers, Allison Shumway, Mark Petersen, Art Frankel, Erin Wirth, Morgan Moschetti 

Past Workshops

Workshops for the 2023 50-State Update of the NSHMs

Workshops for the 2021 Hawaii Hazard Maps

Workshops for the 2018 National Hazard Maps


The U.S. Geological Survey produces National Seismic Hazard Maps that are the basis of seismic provisions of building design codes, earthquake insurance rate structures, and other public policy decision-making tools. Because of the significant safety and financial implications of these maps, they are held to a high level of scrutiny by earthquake engineering and science experts. The National Seismic Hazard Mapping Project, which has responsibility for the maps, has undertaken an extensive process to update these maps. We hold regional and topical open workshops across the country to solicit new information, to discuss potential changes, and to build consensus on the best available science. Workshop participants are welcome to show any information relevant to the topic of seismic hazard in the United States. The workshop presentations inform the community of the current methods, models, and data that are being considered in the update and provide credit to the presenters for their contributions. Moreover, these presentations are important in describing the current state of practice and in providing a historical context of prevalent thoughts of the hazard community at the time the maps were developed. However, all of the information shown at the workshop is pre-decisional, and not all of the information has been published or even reviewed. It is important for individuals accessing the workshop section of this website to understand that the workshop information is not endorsed by the USGS. A similar disclaimer also applies to un-reviewed USGS presentations that typically display impacts of a suite of alternative weighted-models on the seismic hazard maps. These presentations are shown for informational purposed only; the models shown in the presentations will not necessarily be included in the final maps. Final hazard maps will rely on published information, and the documentation will be published as a USGS Open-file report and as journal articles.