page_title: 1867 Manhattan, Kansas earthquake
section_title: Background and geography
hierarchical_section_title: 1867 Manhattan, Kansas earthquake / Background and geography
context_page_description: 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 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, 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.
context_section_description: 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.
  The Nemaha Range lies roughly 50 miles (80 km) east of the Midcontinent rift, which forms a layer of basaltic rock about 1.1 billion years old. This rift extends northward to Lake Superior and the surrounding area and southward to Kansas, then terminates abruptly. Also present in the state is the Central Kansas Uplift, the faults of which produced several small earthquakes during the late 1980s. According to United States Geological Survey geophysicist Don Steeples, earthquakes at the Humboldt Zone have decreased, and activity at the Uplift was increasing as of the 1980s.
  Felt over an area of 193,000 square miles (500,000 km²), with other sources listing the felt area as 300,000 square miles (780,000 km²) or 95,000 square miles (250,000 km²), the 1867 earthquake followed the Midcontinent seismic trend: unlike coastal earthquakes in the United States, events in the central and east-central sectors of the country are spread out over extensive areas. This occurs as a result of the region's stiff soil, and because earthquakes in Kansas tend to occur at a shallow depth. The 1867 Manhattan earthquake remains the largest earthquake to originate in the state, though at least 25 have taken place since, including another powerful earthquake 10 miles (16 km) north of Manhattan in Pottawatomie County. In 2016, a magnitude 5.1 earthquake with an epicenter in Oklahoma shook the Manhattan area. According to a report in the Bulletin of the Seismological Society of America, the frequency of moderately strong earthquakes within the state is between 40 and 45 years. One study found that between December 1977 and June 1989, more than 100 earthquakes were recognized by a seismograph network. All were between 4.0 and 0.8 on the Richter magnitude scale.
caption: The Humboldt Fault (red) and Midcontinent Rift System (green) in Kansas and Nebraska