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1867 Manhattan, Kansas earthquake

Coordinates: 39°30′N 96°42′W / 39.5°N 96.7°W / 39.5; -96.7
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1867 Manhattan earthquake
1867 Manhattan, Kansas earthquake is located in Kansas
1867 Manhattan, Kansas earthquake
UTC time??
Magnitude5.1 ML
Epicenter39°30′N 96°42′W / 39.5°N 96.7°W / 39.5; -96.7[1]
Areas affected United States, Kansas

On April 24, 1867, the 1867 Manhattan earthquake struck Riley County, Kansas. Measuring 5.1 on the Richter scale, the earthquake's epicenter was by the town of Manhattan. To this day, it remains the strongest earthquake to originate in Kansas.

The earthquake had an intensity of VII on the Mercalli intensity scale, and was felt over an area of roughly 193,051 square miles (500,000 km2). It caused largely minor damage, reports of which were confined to Kansas, Iowa, and Missouri, according to the United States Geological Survey.

Manhattan is near the Nemaha Ridge, a long structure that is bounded by several faults. The nearby Humboldt Fault Zone in particular poses a threat to the city even today. Kansas is not known for earthquake activity, but an earthquake could occur at any time.

Background and geography

The earthquake was pinpointed to Manhattan, Kansas, a town just off the connection of the Kansas River and the Big Blue River.[2] Nearby is the anticline Nemaha Ridge, which has been associated with at least a few earthquakes of Kansas. A 300 million year old Precambrian granite range bounded by faults, it hosts the Humboldt Fault Zone, which, in addition to serving as the range's easternmost boundary, has hosted a large portion of the state's earthquakes. Each year, it produces at least several small tremors < magnitude 2.7.[2] It cuts through Permian rock, and according to the Geological Society of America, may actually be a complex fault. Previously, it was believed to be a simple, Precambrian structure.[3] The Nemaha Range is roughly 50 miles (80 km) east of the Midcontinent rift, which forms a layer of basaltic rock around 1100 million years old. This rift extends northward to Lake Superior and the surrrounding area and southward to Kansas, then stops abruptly.[4] Also present in the state is the Central Kansas Uplift, the faults of which produced several small earthquakes during the late 1980s. Between December 1977 and June 1989, more than 200 earthquakes were recognized by a strong seismograph network. All were between 4 and .8 on the Richter magnitude scale.[5]

Felt over an area of 193,051 square miles (500,000 km2), the earthquake followed the Midcontinent seismic trend.[6] Unlike earthquakes on the Western Coast of the US, events in the central and east-central sectors of the country are spread out over extensive areas: for example, the 1968 Illinois earthquake also followed this trend.

The 1867 Manhattan earthquake remains the only notable earthquake to originate in the state,[7] though 25 in total have taken place since.[2] According to the Bulletin of Seismological Society of America, the frequency between earthquakes is between 40 and 45 years.[8]

Damage and casualties

Originating at 20:22 UTC, or around 2:30 local time,[9] the earthquake was assigned a maximum intensity of VII. Minor damage occurred throughout the geographical region. Injuries were reported as well. The earthquake fractured walls, downed chimneys, and interfered with the stability of structures, even loosening stones. In Louisville and Leavenworth, chimneys fell; in Paola, the earthquake destroyed one wall of a large post office building. Waves were observed on the Kansas River, 2 feet (1 m) in height. Isolated reports from Iowa and Missouri, describing fallen and cracked plaster in Dubuque and Chillicothe, compliment additional reports of fallen plaster and roof shingles, damaged wells, and cracked walls.

A series of articles were published by the Chicago Tribune describing the extent of the damage throughout the state of Kansas. "At Kansas City" details that the earthquake jolted homes with a sudden burst, giving off a resonating roar like thunder.[9] "At Leavenworth, Kansas" delves into the reactions of affected citizens.[10]

The earthquake extended into Indiana and Illinois, according to the United States Geological Survey.[6]

Reaction

The Chicago Tribune observed in its article "At Leavenworth, Kansas" that the earthquake was completely unexpected, describing the event as "[...] sudden in its coming and departure." It confirms that earthquakes were not common in earlier time and states that "all were more or less startled, and, indeed, frightened."[10]

Future threat

Despite the fact that Kansas is not seismically active, a strong earthquake could pose significant threats to the state. If an earthquake were to occur, it would likely be along the Nemaha Ridge, which is still active.[8] The Humboldt Fault Zone, a fault just off the Ridge, lies just 12 miles (19 km) eastward of the Tuttle Creek Reservoir near Manhattan. If an earthquake were to occur here, it would likely destroy the dam, releasing 300,000 feet (91,440 m) of water per second and flooding the nearby area, also threatening roughly 13,000 people and 5,900 homes. A moderate earthquake "between 5.7 to 6.6 would cause sand underneath the dam to liquefy into quicksand, causing the dam to spread out and the top to drop up to three feet."[2] A large earthquake would spawn gaps, forcing water to leak and eventually cause the dam to collapse. Any earthquake that could pose a threat occurs on a cycle of roughly 1,800 years, according to the United States Army Corps of Engineers, who studied the area first in 1980.[2]

To counter this threat, the group has galvanized an effort to strengthen the dam. Replacing the sand, which could shift during an earthquake, with more than 350 walls, the group has equipped the dam with sensors. Alarms are connected to these sensors, which would alert nearby citizens to the earthquake.[2]

See also

References

  1. ^ IISEENET (Information Network of Earthquake disaster Prevention Technologies). "Search Parameters". Retrieved 2009-11-04.
  2. ^ a b c d e f Metz, Christine (May 2, 2008). "Earthquakes in Kansas a real threat". Lawrence Journal-World. Retrieved February 11, 2010.
  3. ^ Steeples, Don W. (1979). "Seismicity, faulting, and geophysical anomalies in Nemaha County, Kansas: Relationship to regional structures". Geological Society of America. p. 134-138. Retrieved February 20, 2010. {{cite web}}: Unknown parameter |coauthors= ignored (|author= suggested) (help); Unknown parameter |month= ignored (help)
  4. ^ "Earthquakes in Kansas". Kansas Geological Survey. July 1996. Retrieved February 17, 2010.
  5. ^ "Recording Earthquakes in Kansas". Kansas Geological Survey. July 1996. Retrieved February 17, 2010.
  6. ^ a b "Historic Earthquakes: Manhattan, Riley County, Kansas". United States Geological Survey. October 26, 2009. Retrieved February 10, 2010.
  7. ^ "Historic United States Earthquakes". United States Geological Survey. November 23, 2009. Retrieved February 10, 2010.
  8. ^ a b Merriam, Daniel F. (1956). "History of earthquakes in Kansas". Bulletin of the Seismological Society of America. 46 (2): 87–96. {{cite journal}}: |access-date= requires |url= (help); Unknown parameter |month= ignored (help); line feed character in |journal= at position 41 (help)
  9. ^ a b "At Kansas City". Tribune Company. April 30, 1867. {{cite news}}: |access-date= requires |url= (help)
  10. ^ a b "At Leavenworth, Kansas". Chicago Tribune. Tribune Company. April 30, 1867. {{cite news}}: |access-date= requires |url= (help)
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