New map shows 75 percent of the U.S. at risk of damaging earthquakes

The recent update to the U.S. Geological Survey’s National Seismic Hazard Model (NSHM) reveals a concerning scenario: nearly three-quarters of the United States is at risk of experiencing damaging earthquake shaking.

This alarming study, led by a team of over 50 scientists and engineers, employs a color-coded map to illustrate areas most susceptible to earthquake damage.

This map is the result of comprehensive seismic research, historical geological data, and cutting-edge data collection technologies.

Earthquake risk across the United States

This updated map, specifically requested by Congress, is a critical tool designed to guide engineers and other professionals in mitigating earthquake impacts on vulnerable U.S. communities.

It highlights probable earthquake locations and their potential intensity, a vital aspect for public safety planning.

The NSHM’s latest version, which is the first to provide a comprehensive assessment for all 50 states, builds on earlier versions released in 2018, 2007, and 1998 for the contiguous U.S., Alaska, and Hawaii, respectively.

What sets this iteration apart is its inclusion of nearly 500 newly identified faults capable of producing significant quakes.

This highlights the dynamic nature of earthquake research and the continuous evolution in our understanding of seismic risks.

Altered U.S. earthquake landscape

Mark Petersen, a geophysicist at the USGS and the study’s lead author, emphasized the collaborative nature of this effort.

“This was a massive, multi-year collaborative effort between federal, state and local governments and the private sector,” said Petersen. “The new seismic hazard model represents a touchstone achievement for enhancing public safety.”

One of the most striking findings of the updated model is the increased potential for damaging earthquakes along the central and northeastern U.S. Atlantic Coastal corridor.

Major cities like Washington D.C., Philadelphia, New York, and Boston are now seen as more vulnerable.

Additionally, the model indicates heightened seismic risks in California and Alaska and a greater potential for shaking in Hawaii, informed by recent volcanic activities and seismic unrest.

Improvements in earthquake forecasting

Petersen highlighted the strides made in earthquake forecasting through this model. “Earthquakes are difficult to forecast but we’ve made great strides with this new model,” he noted.

“The update includes more faults, better-characterized land surfaces, and computational advancements in modeling that provide the most detailed view ever of the earthquake risks we face.”

The updated NSHM key findings are crucial and have significant implications for earthquake zones in the United States.

Key findings about U.S. earthquakes

Risk to People

Firstly, it identifies that nearly 75% of the U.S. is at risk of damaging earthquakes and intense ground shaking, placing hundreds of millions of Americans in potential danger.

This finding underscores the vast scale of seismic risks facing the nation.

Widespread Hazard

In addition, the history of seismic activity in the U.S. is widespread and notable.

Over the past 200 years, 37 states have experienced earthquakes exceeding a magnitude of 5, highlighting the extensive geographical spread of earthquake hazards across the country.

Structural Implications

Next, for architects, engineers, and policymakers, the updated model serves as an invaluable resource.

It offers essential insights for the future of building and structural design, guiding how structures across the U.S. should be planned and constructed to withstand seismic events.

This aspect of the model is particularly crucial for enhancing the resilience and safety of new and existing infrastructures.

Unified Approach

Furthermore, a significant advancement in this iteration of the NSHM is its comprehensive scope. For the first time, the model includes all 50 states in a unified seismic hazard assessment.

This achievement reflects a considerable collaborative effort, bringing together various levels of government and sectors to provide a cohesive understanding of seismic risks nationwide.

Not a Prediction

Finally, it’s important to note that the model, while detailed and informative, does not predict earthquakes. Instead, it offers a scientific foundation for assessing the likelihood and potential intensity of future seismic events.

This distinction is vital in understanding the model’s role as a tool for preparedness and risk assessment rather than as a predictive mechanism for specific earthquake occurrences.

In summary, the updated NSHM underscores the pressing need for preparedness and resilience in the face of seismic threats across the United States.

It serves as a vital tool for professionals and policymakers, guiding them in protecting communities and infrastructure from the unpredictable but inevitable occurrence of earthquakes.

The full study was published in the journal Earthquake Spectra.

—–

Like what you read? Subscribe to our newsletter for engaging articles, exclusive content, and the latest updates.

Check us out on EarthSnap, a free app brought to you by Eric Ralls and Earth.com.

—–