1867 Manhattan, Kansas earthquake
 Manhattan
 |
|
| UTC time | ?? |
|---|---|
| ISC event | |
| USGS-ANSS | |
| Local date | April 24, 1867 |
| Local time | 14:30 |
| Magnitude | 5.1 Mfa |
| Epicenter | 39°12′N 96°18′W / 39.2°N 96.3°WCoordinates: 39°12′N 96°18′W / 39.2°N 96.3°W |
| Areas affected |
Kansas United States |
| Max. intensity | VII (Very strong) |
| Casualties | Several injured |
The 1867 Manhattan earthquake struck Riley County, Kansas, in the United States on April 24, 1867 at 20:22 UTC, or about 14:30 local time. The strongest earthquake to originate in the state, it measured 5.1 on a seismic scale that is based on an isoseismal map or the event's felt area. The earthquake's epicenter was near the town of Manhattan.
The earthquake had a maximum perceived intensity of VII (Very strong) on the Mercalli intensity scale. It caused minor damage, reports of which were confined to Kansas, Iowa, and Missouri, according to the United States Geological Survey. Felt over an area of 200,000 square miles (520,000 km2), the earthquake reached the states of Indiana, Illinois, and possibly Ohio, though the latter reports have been questioned.
Manhattan is near the Nemaha Ridge, a long anticline structure that is bounded by several faults. The nearby Humboldt Fault Zone in particular poses a threat to the city. Kansas is not known for earthquake activity, but an earthquake could occur at any time. A 2016 hazard map from the United States Geological Survey estimated a 1% or lower risk for a major earthquake in Kansas for the following year, though scientists from the agency think an earthquake of magnitude 7.0 remains possible.
The earthquake's epicenter was near Manhattan, Kansas, a town just off the confluence of the Kansas River and the Big Blue River. Manhattan lies near the Nemaha Ridge, an anticline and 300‑million-year-old Precambrian granite range bounded by faults, which likely produced the earthquake. It hosts the Humboldt Fault Zone, which, in addition to serving as the range's easternmost boundary, has produced a large portion of the state's earthquakes. A normal, or dip-slip fault, it is responsible for at least several small tremors smaller than magnitude 2.7 each year. The fault cuts through Permian rock. Despite being previously thought to be a simple, Precambrian structure, according to the Geological Society of America, it may be a complex fault.
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