The largest motions are due to the seismic S-wave, followed by surface waves. The Mineral earthquake had a very prolific aftershock sequence, which is still being studied.
Geological Survey installed many seismograph stations in the epicentral area. The small red symbols show the epicenters of aftershock epicenters occurring from August 25, until January 1, Wu and Chapman, The black symbols show the locations of temporary seismic stations deployed to record the aftershocks.
McNamara, D. Benz, R. Herrmann, E. Sediments are weaker than the underlying bedrock and therefore move more, while also trapping more energy. Amplification by sediments has been seen in earthquakes in other areas, for example in the concentration of damage in the Marina district of San Francisco during the Loma Prieta earthquake, but the strength of this effect was not as well known for the sediments along the East Coast.
It is now recognized that this amplification can be severe in the eastern U. USGS scientists found that the strength of ground shaking from the Mineral earthquake was substantially greater to the northeast than in other directions. This direction is nearly parallel to the orientation of the Appalachian Mountains and the eastern edge of the continent, which shows the influence of large-scale features like mountain ranges on ground shaking. A similar pattern was observed in the magnitude 5.
Knowing the amplification caused by these sediments and the direction of shaking will help emergency managers identify communities that may be more vulnerable to shaking. This knowledge will help the USGS refine its seismic hazard maps, which estimate the strength of ground shaking that can be expected during earthquakes in each area of the country.
These insights can also be used by emergency managers when planning for and responding to disasters; state and local governments as they refine building codes; and architects and engineers as they design and renovate buildings to mitigate the effects of future earthquakes. In addition, the science helps inform planning for major infrastructure investments such as dams and reservoirs. Earthquakes magnitude 3. The yellow star marks the epicenter of the magnitude 5.
The earthquake occurred in what is known by scientists as the Central Virginia Seismic Zone , which has a long history of occasional earthquakes. Identifying the locations and magnitudes of past earthquakes and the likelihood of future earthquakes in the region is an area of active research.
The USGS and partners deployed portable seismographs immediately after the Mineral earthquake to supplement existing seismometers in the region for recording aftershocks. More than aftershocks, including six greater than magnitude 3, were identified in the year after the earthquake, and nearly 4, have been recognized from subsequent analyses so far.
This knowledge is helping to better understand fault lines and earthquake sources and refine estimates on the number of aftershocks that can be expected. The locations and strength of ground shaking were also measured on established seismic stations throughout the U.
The intensity data collected by the U. More than , This map summarizes two and a third centuries of earthquake activity. The seismic history consists of letters, journals, diaries, and newspaper and scholarly articles that supplement seismograph recordings seismograms dating from the early twentieth century to the present.
All of the pre-instrumental historical earthquakes were large enough to Blanpied discusses how scientists are using the August 23 earthquake to inform estimates of the region's seismic hazard. Mike Blanpied discusses whether a similar event could occur again in the region in the near future, and in an earthquake, what you can do to stay stay safe. Watch video interviews with four people discussing their experiences near the epicenter of the magnitude 5.
Tens of millions of people in the eastern U. The magnitude 5. It caused extensive damage in central Virginia and was likely felt by more people than any other earthquake in U. A live, online chat about East Coast earthquakes and the Virginia 5. A magnitude 5. Skip to main content. Search Search.
Earthquake Hazards. Science Center Objects Overview Publications Multimedia On August 23, tens of millions of people along the East Coast suddenly felt the earth shaking from the largest earthquake in the eastern U. Below are publications associated with this project. Filter Total Items: 6.
Year Published: The Mineral, Virginia, earthquake and its significance for seismic hazards in eastern North America: overview and synthesis The 23 August Mw moment magnitude 5. Horton, J. Wright; Chapman, Martin C.
View Citation. Parts of the Pentagon, the White House, the U. Capitol and federal agencies were evacuated. Buildings in Ohio, West Virginia, Delaware, and states all throughout the region were evacuated due to the quake as well. The earthquake struck an area that historically is not seismically active.
According to the U. Geological Survey, the largest recorded earthquake in Virginia history was a 5. The Mineral quake was the largest to have occurred east of the Rocky Mountains since that one. There is a fault line in Bergton, which runs parallel to the Blue Ridge Mountains, and that line is why the Louisa quake was felt from Canada to Georgia.
The energy from the quake traveled through the mountain ridge-lines. Hundreds of aftershocks were felt in Louisa later that night and numerous earthquakes have been felt in the area since then.
This data comes from the USGS. The largest earthquakes are the red dots with the information on the earthquake detailed. The Central Virginia seismic zone which is where the Mineral earthquake occurred has quite the history of earthquakes, and you can see the cluster of historical earthquakes in that area. Ah, the big blizzard earthquake of April 9, Can you imagine. Spring snow all day, it starts to accumulate at night and BAM, there's an earthquake- in Virginia!?
Heavy snow did a number on the fruit trees. One of the more fascinating earthquakes in our history is the Luray earthquake of This was an April snow day with heavy, wet snow all day.
Around 9 p. According to reports windows shattered and plaster walls and ceilings cracked. If you want to read more on the research that has been done since the Mineral earthquake:. This link goes into greater detail with the difference in East Coast and West Coast earthquakes.
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