Earthquakes are one of the most devastating natural disasters that can strike anywhere, anytime, without warning. They can cause massive damage to buildings, infrastructure, and human lives.
According to the U.S. Geological Survey (USGS), about 250 million people in the United States face potential earthquake risks. But how can we know where and when the next big quake will hit? And how can we prepare for it?
A new map, released by the USGS in June 2021, may provide some answers. The map, called the National Seismic Hazard Model (NSHM), shows the probability of damaging earthquakes over the next 100 years across the nation.
It is based on data from some 130,000 quakes recorded in seismic networks since 1900. The map reveals some surprising and alarming findings about the hidden dangers lurking beneath the surface.
The Surprising Hotspots of Seismic Activity(Photo : FREDERIC J. BROWN/AFP via Getty Images)
The NSHM is not the first map of its kind. The USGS has been producing seismic hazard maps since the 1970s, updating them every six years.
However, the latest version incorporates new data and methods that improve the accuracy and resolution of the map. It also covers a larger area, extending to Alaska, Hawaii, Puerto Rico, and the U.S. Virgin Islands.
One of the most striking features of the NSHM is that it shows areas that were previously underestimated for their seismic activity and hazard risks.
For example, the map reveals that parts of the East Coast, the Midwest, and the South have a higher chance of experiencing damaging earthquakes than previously thought.
These regions are not known for having active faults, but they have experienced some large and destructive quakes in the past, such as the 1811-1812 New Madrid earthquakes in Missouri and the 1886 Charleston earthquake in South Carolina.
Another surprising hotspot is Oklahoma, which has seen a dramatic increase in the number of earthquakes in the past decade.
The NSHM attributes this phenomenon to the injection of wastewater from oil and gas production into deep wells, which can trigger seismic activity along existing faults.
The map also shows that some areas in California, such as the San Francisco Bay Area and Los Angeles, have a lower probability of damaging earthquakes than previously estimated, due to better understanding of the fault geometry and slip rates.
The map serves as a crucial tool for engineers, policymakers, and planners who are responsible for designing and enforcing building codes, developing emergency response plans, and allocating resources for mitigation and recovery.
The map can help them identify the most vulnerable areas and structures, and prioritize the actions needed to reduce the potential impacts of earthquakes.
The NSHM also serves as a wake-up call for the public, especially those who live in areas that are newly identified as high-risk zones.
The map reminds them that earthquakes can happen anywhere, and that they need to be aware and prepared for the possibility of a disaster.
The USGS recommends that people take some simple steps to protect themselves and their families, such as securing furniture and appliances, creating an emergency kit and plan, and practicing how to drop, cover, and hold on during a quake.
In conclusion, the NSHM is a groundbreaking achievement in seismology and risk assessment, offering invaluable insights that could potentially save millions of lives from earthquakes.
The map is not a prediction, but a projection of the likelihood and severity of future seismic events. It is not a static product, but a dynamic and evolving one, that will be updated as new data and knowledge become available.
The map is not a final word, but a starting point, for a more informed and resilient society.
