1897 Giles County earthquake

Earthquakes in Virginia October 2026 October 2026 USA Virginia Virginia 37.3 -80.7 Bullseye1.png 40 yes 250 right yes ushis334 1897 5 31 13:58 EST b 5.8 y, s 5.9 y 37.3 N 80.7 W United States 8 The 1897 Giles County earthquake is one of the strongest in the state of Virginia and in the East Coast of the United States. The earthquake which measured b 5.8 y or s 5.9 y, struck Giles County on May 31 at 13:58 EST. While there were no casualties, the earthquake caused considerable damage to chimneys in Virginia and Tennessee, and was felt for over a wide area in several states. The earthquake was likely the result of faulting in the Giles County seismic zone, where Precambrian to early Paleozoic normal faults related to the early formation of the Iapetus Ocean have been reactivated by present-day tectonic stresses within the North American plate. Earthquake The earthquake struck on May 31 at 13:58 EST with an epicenter in Giles County, Virginia, near the border with West Virginia.M 5.6 - The 1897 Giles County, Virginia Earthquake 2026 ushis334 Its estimated body-wave and surface-wave magnitudes were 5.8 and 5.9, respectively. It is the largest earthquake in Virginia, with a magnitude close to that of the 2011 earthquake.Powell Devin Magnitude 5.8 earthquake hits Virginia https://www.sciencenews.org/article/magnitude-58-earthquake-hits-virginia 4 August 2026 Science News 23 August 2011 Prior to the mainshock, on May 3, an intensity VI (Strong) foreshock with an epicenter near Pulaski dislodged some bricks from old chimneys in Giles County. It was also accompanied by "considerable noise". Similar noises were heard in the area leading up to the earthquake. About a week before, the Richmond Dispatch said residents of the county were disturbed by "subterranean noises" likened to the sound of distant artillery. These effects also continued to be felt in Pearisburg after the earthquake, in addition to additional tremors, but after some time, became rarer and weaker.Bollinger G. A. Hopper Margaret G. Virginia's two largest earthquakes—December 22, 1875 and May 31, 1897 Bulletin of the Seismological Society of America 1971 61 4 1033–1039 10.1785/BSSA0610041033 Aftershocks continued to be felt in 1902 or as late as 1917. No significant earthquakes would be recorded in the region until 1959, and a b 4.9 event on November 20, 1969 would represent the largest earthquake in the area since 1897.Bollinger G. A. Wheeler Russell L. The Giles County, Virginia, Seismic Zone Science 1983 219 4588 1063-1065 https://www.jstor.org/stable/1690155 Seismologist Susan Hough compared the intensity distribution of the 1897 earthquake, based on historical records, and the 2011 earthquake, and concluded that the former event was smaller than moment magnitude (w) 5.8. Hough highlighted that the felt area of the 2011 earthquake extended farther west than during the 1897 earthquake despire the earlier quake having an epicenter west of the 2011 event. She also assigned intensity values for some reports of the earthquake based on the U.S. Geological Survey's Did You Feel It? (DYFI) citizen science questionnare used to crowdsource data for earthquake shaking intensity. Based on comparing the DYFI-informed data and implementing attenuation relation models, the computed earthquake size is w 5.5. The earthquake caused landslides and derailed a freight train in Giles County. In Narrows, the ground "rolled in an undulating motion" and springs became muddy or stopped flowing. Similarly, at Pearisburg, the springwater stopped flowing. Many chimneys collapsed or sustained heavy damage, and cracks formed in the walls of old brick houses in Pearisburg. Damage to chimneys was also reported in Charlotte, Oxford, Raleigh, and Winston, North Carolina; and Knoxville, Tennessee.Stover C.W. Coffman J.L. Seismicity of the United States, 1568–1989 (Revised) https://pubs.usgs.gov/publication/pp1527 1527 1993 USGS Numbered Series United States Geological Survey 377–378 In Indianapolis, Indiana, the shaking was most perceptible on tall buildings; a similar account was also made in Baltimore, Maryland.Hough Susan E. Initial Assessment of the Intensity Distribution of the 2011 Mw 5.8 Mineral, Virginia, Earthquake Seismological Research Letters 2011 83 4 10.1785/0220110140 Intensity thumb|right|An isoseismal map for the mainshock by C. W. Stover and J. L. Coffman The earthquake was felt across a 280,000 to 300,000 km2 area extending from as far north as Cleveland, Ohio; and as far south as Savannah, Georgia, where the intensity was II–IV (Light–Weak). Many reports of collapsed chimneys and "changes in the flow of springs" earned the shock maximum intesity of VII–VIII (Very Strong–Severe) on the Modified Mercalli intensity scale. In C. W. Stover's and J. L. Coffman's isoseismal map, the meizoseismal area was assigned to a northeast-trending oblong area from Lynchburg, westwards to Bluefield (in West Virginia), and from southern Giles County to Bristol (in Tennessee). Intensity VIII was assigned to a small circular region near the epicenter while all contours of lower intensities generally feature a northeast trending axis. The intensity VI contour covers much of western Virginia, eastern Tennessee, and a small part of southern West Virginia. The intensity V isoseismal line extend approximately east–northeast from Norfolk, Virginia to Knoxville, Tennessee. Inside the intensity V contour, in the Piedmont, there is an isolated northwest-trending intensity VI area with Richmond at its northwest end. In another isoseismal map created by geologists Margaret G. Hopper and G. A. Bollinger, a large portion of the southern half of Virginia, the northern half of North Carolina and a small area in West Virginia felt intensity VI (Strong) shaking. They concluded from descriptions of damage that the intensity in the epicenter area and Pearisburg did not exceed VIII. The shaking was weaker in the central Piedmont south of Winchester. However, in the neighboring coastal plain, there was an isolated area of stronger shaking. The intensity V (Moderate) isoseismal line is drawn roughly parallel to the intensity VI isoseismal line, and is assigned to an area extending along the Ohio River Valley northwards to Cincinnati. The IV and III contours lines are drawn past most of West Virginia and Ohio, and into parts of Tennessee, Pennsylvania, Indiana and Kentucky. In eastern Tennessee, which felt the earthquake with intensity V, there is a small elliptical region of stronger shaking corresponding to VI–VII. Geology Intraplate earthquake The earthquake is likely associated with seismic activity on the Giles County seismic zone in southwestern Virginia. It is a seismically active region about 40 by 10 km trending northeast and located near Pearisburg and Narrows. Earthquakes in the seismic zone have shallow focal depths ranging from 5 to 25 km corresponding to the upper crust, based on a study of 12 earthquakes from 1959 to 1980. This seismic zone likely represents a reverse fault dipping 80° northwest in response to compressive intraplate tectonic stress.Bollinger G. A. Wheeler Russell L. The Giles County, Virginia, seismogenic zone-- Seismological results and geological interpretations 1982 82-585 10.3133/ofr82585 https://www.usgs.gov/publications/giles-county-virginia-seismogenic-zone-seismological-results-and-geological USGS Numbered Series United States Geological Survey The shallow subsurface geology of Giles County comprise a heavily deformed and faulted Paleozoic sedimentary layer extending to a depth of 3 to 6 km. This layer is typically carbonates of the Cambrian and Ordovician, and clastic rocks of the Ordovician, Silurian, Devonian, and Mississippian which formed during orogenies such as the Alleghanian orogeny. Beneath the Paleozoic sediments are near-horizontal detachments that have displaced the overlying strata over several tens of kilometers and separated them from the crystalline basement. These detachments are also related to the Alleghanian orogeny. The Giles County seismic zone is situated entirely within the Precambrian crystalline basement. It most likely originated from late Precambrian to early Paleozoic continental rifting along normal faults which eventually formed the Iapetus Ocean. These normal faults formed within the rifted crystalline basement. Giles County is located within a 100 to 200 km wide rift zone and near the former continental margin of the Iapetus Ocean. In the present, the North American plate experiences east–northeast compression, reactivating pre-existing normal faults as reverse faults. See also Virginia Earth sciences List of earthquakes in the United States 2020 Sparta earthquake References Category:Earthquakes in the United States Category:Giles County, Virginia Category:1897 earthquakes Category:May 1897 in the United States Category:1897 natural disasters in the United States Category:Geology of Virginia Category:Natural disasters in Virginia Category:1897 in Virginia Category:1897 in West Virginia