South Carolina earthquakes occur with the greatest frequency along the central coastline of the state, in the Charleston area. South Carolina is the most seismically active state on the east coast.[1] At 7.3 magnitude, the Charleston earthquake of 1886 was the largest quake to ever hit the Eastern United States. This earthquake killed at least 60 people and destroyed much of the city. Aftershocks, some of them large enough to be damaging by themselves, continued for years.
Faults in this region are difficult to study at the surface due to thick sedimentation on top of them. Many of the ancient faults are within plates rather than along plate boundaries.[2][3]
Prehistoric earthquakes of similar size to the 1886 shock have occurred in coastal South Carolina at intervals of several centuries to several thousands of years. In recent decades, damaging earthquakes much smaller than that of 1886 have occurred every decade or two, most recently in 2014 (magnitude 4.1). Typically, smaller earthquakes are felt each year or two. East of the Rockies, an earthquake shakes the ground over an area up to ten times the area typically shaken by a similar magnitude earthquake on the west coast. For example, an eastern magnitude 4.0 earthquake typically can be felt at many locations as far as 100km (60mi) from where it occurred, and it might or might not cause damage near its source. An eastern magnitude 5.5 earthquake usually can be felt out to 500km (300mi) in most directions and can cause damage out to 40km (25 miles).[3]
Tectonic setting
Earthquakes occur deep within bedrock. Most bedrock beneath the Charleston area was assembled as continents collided to form a supercontinent about 500-300 million years ago, raising the Appalachian Mountains. Most of the rest of the bedrock formed when the supercontinent rifted apart about 200 million years ago to form what are now the southeastern U.S., the Atlantic Ocean, and Africa. Today the Charleston area is far from the nearest plate boundary, which is in the Caribbean Sea.[3]
At plate boundaries, the relation of earthquakes to faults is comparatively well understood. In contrast, in the Charleston area, as in most other parts of the U.S. east of the Rockies, the relation is enigmatic. Bedrock in the area is laced with faults that date mainly from the formation of the Appalachians and the birth of the Atlantic. However, in the Charleston area bedrock and its faults are buried beneath sand, silt, clay, and soft sedimentary rocks that may be as thick as 3km (2 miles). Accordingly, few of the area's earthquakes can be linked to known faults. As in most other regions east of the Rockies, the best guide to earthquake hazards is the earthquakes themselves.[3]
Charleston earthquake or 1886.Charleston earthquake or 1886.
An estimated $23 million ($186.51million in 2023) in damage was caused by one of the great earthquakes in United States history in 1886. Charleston and nearby cities suffered most of the damage, although points as far as 160 kilometers (100mi) away were strongly shaken. Many of the 20 earthquakes of intensity V or greater (Mercalli intensity scale) that centered within South Carolina occurred near Charleston. A 1924 shock in the western part of the State was felt over 154,000 square kilometers (59,000sqmi). Several earthquakes outside the State borders were felt strongly in South Carolina.
The August 31, 1886 Charleston earthquake was initially perceived in that city as a barely perceptible tremor, then a sound like a heavy body rolling along; the sound became a roar, all movable objects began to shake and rattle, and the tremor became a rude, rapid quiver. The first shock was at 9:51p.m. and lasted 35 to 40 seconds. A strong aftershock occurred 8 minutes later. Six additional shocks followed during the next 24 hours. Few buildings escaped damage and many were totally destroyed. Chimneys of at least 14,000 houses were destroyed. The maximum intensity has been estimated at X.
Two strong aftershocks were reported on October 22, 1886, and another on November 5. The first of these was felt (intensity VI) in Charleston, at Atlanta and Augusta, Georgia, and at other towns. The second shock was intensity VII in Summerville. which received significant damage from the August 31 earthquake. Another tremor caused intensity VI effects on November 5 in Charleston and was felt over the same area as the previous aftershocks. The total felt area covered approximately 78,000 square kilometers (30,000sqmi).[4]
Other quakes
An earthquake of January 26, 1860 at 7 p.m., described as "the severest one felt in many years," was felt throughout the state and as far away as Macon, Georgia.[5]
On January 23, 1903, houses were shaken strongly (intensity VI) in the area of the South Carolina - Georgia border near Savannah. Intensity IV - V effects were noted at Charleston, III - IV at Columbia, and III at Augusta, Georgia.
A moderate shock affected Charleston, Augusta, and Savannah on April 19, 1907. Dishes rattled and objects were thrown from shelves throughout the 26,000 square kilometer area. A somewhat stronger earthquake caused some damage to chimneys (intensity VII) at Summerville on June 12, 1912. The shock was felt at Charleston with intensity VI and also was felt as far as Brunswick and Macon, Georgia; Greenville, South Carolina, and Wilmington, North Carolina, an area of about 90,000 square kilometers.
The Union County area was shaken with an intensity VI - VII earthquake about 6 months later (January 1, 1913). At Union, cracks appeared in many brick buildings and many chimneys were damaged. The total felt area, roughly elliptical in shape, covered approximately 111,000 square kilometers.
Another earthquake affected the Summerville area on September 22, 1914. Pictures on walls were displaced (intensity V). The shock was preceded by a noise like a train approaching from a distance. The shock was felt (intensity IV) at Charleston and with less intensity at Augusta, Macon, and Savannah, Georgia, an area of about 78,000 square kilometers.[4]
Pickens County was the apparent center of an October 20, 1924, earthquake which shook most of South Carolina and western North Carolina, northeastern Georgia, and eastern Tennessee. The area affected was approximately 145,000 square kilometers. Highest intensities were reported at Pickens, Walhalla, Brevard, and Hendersonville, North Carolina. Buildings were shaken, and furniture was overturned (intensity V). A loud roar accompanied the shock.
On July 26, 1945, an earthquake centered in the vicinity of Lake Murray, about 50 kilometers west of Columbia, was felt over 65,000 square kilometers, including part of Georgia, North Carolina, and Tennessee. No damage was noted and only intensity IV - V effects were observed in the epicentral region.
Moderately strong shocks occurred near Charleston on November 19, 1952, August 3, 1959, March 12, 1960, July 23, 1960, and October 23, 1967. The 1959 disturbance caused minor damage (intensity VI) at Charleston, Summerville, and Wadmalaw Island. Chimneys were damaged, plaster cracked and fell, walls cracked, and objects fell from shelves. Cracked plaster was also reported from Columbia, Johns Island, Meggett, and Pierpont in South Carolina and from Augusta, Georgia. The total affected area was about 65,000 square kilometers. The other earthquakes did not exceed intensity V. The epicenter for the March 12, 1960, tremor was off the coast of South Carolina; Augusta, Georgia, and Greensboro, North Carolina, also felt this shock.
Moderate earthquakes also awakened many residents (intensity V) at Anderson on October 20, 1958, and caused minor damage (cracked and fallen plaster - intensity V) at Chesterfield on October 26, 1959. Another shock on April 20, 1964, was felt strongly (intensity V) at Gaston and Jenkinsville. Places in Fairfield, Florence, Lexington, and Richland Counties also reported the tremors. Several windows were broken in Bowman and Orangeburg (intensity V) from a magnitude 3.4 earthquake on May 19, 1971. Two small shocks, about 3 hours apart, were felt in western South Carolina July 13, 1971. The main shock at 7:42a.m. edt was felt over approximately 5,200 square kilometers, including two places in Georgia. The tremor was felt by all in Newry; many were frightened by the loud Earth noises (intensity VI), hanging objects swung violently, and furniture shifted.[4]
2002 Seabrook Island earthquake
On Monday, November 11, 2002, areas near Seabrook Island, South Carolina experienced a magnitude 4.4 earthquake. The earthquake occurred at a depth of 3.1 miles (5.0km), 16 miles southeast of Seabrook Island at 32 degrees 22.0 minutes north (32.366N), 80 degrees. 4.4 minutes west (80.073W). There were no reports of damage or injuries.[6]
Valentine's Day earthquake 2014
On Friday, February 14, 2014 at 10:23p.m., an earthquake occurred in the midlands of SC. The epicenter was located near Edgefield SC and could be felt all over SC, Georgia, and Western North Carolina. It was reported to have been a 4.1 earthquake, which is rare for South Carolina.[7]
Kershaw County Quakes
In late 2021 and most of 2022, southeastern Kershaw County experienced over 80 earthquakes, 11 of which exceeded a 2.5 magnitude. 6 of the quakes exceeded a 3.0 magnitude, the largest of which registering at a 3.6.[8]
Related Research Articles
The 1886 Charleston earthquake in South Carolina occurred about 9:50 p.m. local time August 31. It caused 60 deaths and $5–6 million in damage to 2,000 buildings in the Southeastern United States. It is one of the most powerful and damaging earthquakes to hit the East Coast of the United States.
The 1987 Whittier Narrows earthquake occurred in the southern San Gabriel Valley and surrounding communities of Southern California, United States, at 7:42 a.m. PDT on October 1. The moderate magnitude 5.9 blind thrust earthquake was centered several miles north of Whittier in the town of Rosemead, had a relatively shallow depth, and was felt throughout southern California and southern Nevada. Many homes and businesses were affected, along with roadway disruptions, mainly in Los Angeles and Orange counties. Damage estimates ranged from $213–358 million, with 200 injuries, three directly-related deaths, and five additional fatalities that were associated with the event.
The 2006 Gulf of Mexico earthquake occurred in the eastern Gulf of Mexico on September 10 at 10:56 AM Eastern Daylight Time. The intraplate earthquake measured 5.9 on the moment magnitude scale and its epicenter was located about 250 miles (400 km) west-southwest of Anna Maria, Florida. The event was felt throughout much of the Gulf Coast of the United States and was the second earthquake of magnitude 5 or greater in the Gulf during 2006. Felt intensities, as measured on the Mercalli intensity scale, were as high as IV (Light) in Florida, with parts of Georgia at III (Weak).
The 1993 Scotts Mills earthquake, also known as the "Spring break quake", occurred in the U.S. state of Oregon on March 25 at 5:34 AM Pacific Standard Time. With a moment magnitude of 5.6 and a maximum perceived intensity of VII on the Mercalli intensity scale, it was the largest earthquake in the Pacific Northwest since the Elk Lake and Goat Rocks earthquakes of 1981. Ground motion was widely felt in Oregon's Willamette Valley, the Portland metropolitan area, and as far north as the Puget Sound area near Seattle, Washington.
The 2008 Illinois earthquake was one of the largest earthquakes ever recorded in the Midwest state of Illinois. This moderate strike-slip shock measured 5.2 on the moment magnitude scale and had a maximum Mercalli intensity of VII (Very strong). It occurred at 04:36:59 local time on April 18 near Bellmont and Mount Carmel, Illinois, within the Wabash Valley Seismic Zone. Earthquakes in this part of the country are often felt at great distances.
The 1986 Chalfant Valley earthquake struck southern Mono County near Bishop and Chalfant, California at 07:42:28 Pacific Daylight Time on July 21. With a moment magnitude of 6.2 and a maximum Mercalli intensity of VI (Strong), the shock injured two people and caused property damage estimated at $2.7 million in the affected areas. There was a significant foreshock and aftershock sequence that included a few moderate events, and was the last in a series of three earthquakes that affected southern California and the northern Owens Valley in July 1986.
The 1985 Rapel Lake earthquake occurred on 8 April at 21:56:59 local time with a moment magnitude of 7.2 and a maximum perceived intensity of VI (Strong). The shock was centered 75 kilometres (47 mi) southwest of Santiago, Chile, with a focal depth of 37.8 km (23 mi).
The 1872 North Cascades earthquake occurred at 9:40 p.m. local time on December 14 in central Washington Territory. A maximum Mercalli intensity of VIII (Severe) was assessed for several locations, though less intense shaking was observed at many other locations in Washington, Oregon, and British Columbia. Some of these intermediate outlying areas reported V (Moderate) to VII shaking, but intensities as high as IV (Light) were reported as far distant as Idaho and Montana. Due to the remote location of the mainshock and a series of strong aftershocks, damage to structures was limited to a few cabins close to the areas of the highest intensity.
The 1948 Desert Hot Springs earthquake occurred on December 4 at 3:43 p.m. Pacific Standard Time with a moment magnitude of 6.4 and a maximum Mercalli intensity of VII. The shock was felt from the central coast of California in the north, and to Baja California in the south, and came at a time when earthquake research in southern California resumed following the Second World War. It was one of two events in the 20th century that have occurred near a complex region of the southern San Andreas Fault system where it traverses the San Gorgonio Pass and the northern Coachella Valley. Damage was not severe, but some serious injuries occurred, and aftershocks continued until 1957.
The 2011 Kütahya earthquake struck near a populous region of western Turkey at 23:15 EEST (20:15 UTC) on 19 May with a moment magnitude of 5.8 and a maximum Mercalli intensity of VII. With an epicenter just to the east of Simav, it occurred at an estimated depth of 9.1 kilometers (5.7 mi), resulting in strong shaking in much of Kütahya.
The 1979 Imperial Valley earthquake occurred at 16:16 Pacific Daylight Time on 15 October just south of the Mexico–United States border. It affected Imperial Valley in Southern California and Mexicali Valley in northern Baja California. The earthquake had a relatively shallow hypocenter and caused property damage in the United States estimated at US$30 million. The irrigation systems in the Imperial Valley were badly affected, but no deaths occurred. It was the largest earthquake to occur in the contiguous United States since the 1971 San Fernando earthquake eight years earlier.
The geology of New Hampshire is similar to that of the rest of New England in comprising a series of metamorphosed sedimentary and volcanic rocks of Late Proterozoic to Devonian age, intruded by many plutons and dikes ranging in age from Late Proterozoic to early Cretaceous. New Hampshire is known as "the Granite State", but less than half is underlain by granite; much of it is schist or gneiss, both of which are metamorphic rocks.
The 1898 Mare Island earthquake occurred in Northern California on March 30 at 23:43 local time with a moment magnitude of 5.8–6.4 and a maximum Mercalli intensity of VIII–IX (Severe–Violent). Its area of perceptibility included much of northern and central California and western Nevada. Damage amounted to $350,000 and was most pronounced on Mare Island, a peninsula in northern San Francisco Bay. While relatively strong effects there were attributed to vulnerable buildings, moderate effects elsewhere in the San Francisco Bay Area consisted of damaged or partially collapsed structures, and there were media reports of a small tsunami and mostly mild aftershocks that followed.
The 1934 Hansel Valley earthquake occurred on March 12 at approximately 8:05 a.m. MST with a moment magnitude of 6.6 and a maximum Mercalli intensity of VIII (Severe). The shock originated in the Hansel Valley at the north end of the Great Salt Lake in Utah in the United States. Damage was mostly confined to vulnerable buildings, and two people died. The dip-slip (normal) fault that generated the shock ruptured the surface of the ground and other geologic features were documented. A large aftershock occurred three hours after the initial event and may have caused additional damage.
The 2020 Central Idaho earthquake occurred in the western United States on March 31, 2020, at 5:52 PM MDT, near Ruffneck Peak in the Sawtooth Mountains of central Idaho, 72 miles (116 km) northeast of Boise and 19 miles (31 km) northwest of Stanley. It had a magnitude of 6.5 and was felt with a maximum intensity of VIII.
The 1921 Sevier Valley earthquake was a series of three earthquakes. The primary quake was a magnitude Mw6.3 earthquake that occurred on Thursday, 29 September 1921 at approximately 7:12 AM MT in Elsinore, Utah, United States. The first aftershock occurred in the evening on the same day, and a second aftershock occurred two days later on 1 October. No people were killed in the quake or in the subsequent aftershocks.
The 1990 Carlentini earthquake occurred off the Sicilian coast, 20 km east northeast from the town of Augusta, Sicily on 13 December at 01:24 local time. The moderately-sized earthquake measuring 5.6 on the moment magnitude scale (Mw ) resulted in the deaths of 19 people and caused at least 200 injuries. It also inflicted significant damage in the region, leaving 2,500 homeless.
An earthquake struck approximately 53 kilometres SSE of the town of Mansfield, in the Victorian Alps of Australia on 22 September 2021, at 09:15 local time. The earthquake measured 5.9 on the moment magnitude scale. The earthquake caused minor structural damage in parts of Melbourne and left one person injured. The earthquake was also felt in New South Wales, Australian Capital Territory, South Australia and Tasmania. The earthquake was substantially stronger than the 1989 Newcastle earthquake that measured 5.6 and killed 13 people.
The 2021 Lasithi earthquake was a magnitude 6.4 Mw earthquake with a maximum intensity of VIII (Severe) on the Modified Mercalli Intensity Scale which occurred on October 12, 2021, 12:24 (UTC+3:30) off the island of Crete. The quake was also felt at low intensity as far as Cairo and Istanbul.
The 1895 Charleston earthquake, also known as the Halloween earthquake, occurred on October 31, at 05:07 CST near Charleston, Missouri. It had an estimated moment magnitude of 5.8–6.6 and evaluated Modified Mercalli intensity of VIII (Severe). The earthquake caused substantial property damage in the states of Missouri, Illinois, Ohio, Alabama, Iowa, Kentucky, Indiana, and Tennessee. Shaking was widespread, being felt across 23 states and even in Canada. At least two people died and seven were injured.
↑ (Abridged from Seismicity of the United States, 1568–1989 (Revised), by Carl W. Stover and Jerry L. Coffman, U.S. Geological Survey Professional Paper 1527, United States Government Printing Office, Washington: 1993.)
1 2 3 von Hake, Carl A. (October 21, 2009). "South Carolina Earthquake History". South Carolina Earthquake Information. U.S. Geological Survey. Retrieved 2011-09-15. South Carolina averages 20 earthquakes a year" says research team from College of Charleston.
↑ "Earthquake". The Charleston Daily Courier. 1860-01-28. p.2. Retrieved 2023-08-09.
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