Editing Manhattan, Kansas (section)

===Geographic features===
[[File:Flint Hills Discovery Center.JPG|thumb|right|[[Flint Hills Discovery Center]]]]
[[File:Rocky Ford spillway in Manhattan Kansas.jpg|thumb|Rocky Ford spillway fishing area on the [[Big Blue River (Kansas)|Big Blue River]] (2021)]]
Manhattan is in the [[Flint Hills]] region of Kansas, which consists of continuous rolling hills covered in tall grasses. However, the downtown area – Manhattan's original site – was built on a broad, flat [[floodplain]] at the junction of the Kansas and Big Blue rivers. Manhattan is the largest town in the Flint Hills, and is home to the [[Flint Hills Discovery Center]].

[[Tuttle Creek Reservoir]] is {{convert|5|mi|km|0}} north of Manhattan. The lake was formed when the Big Blue River was dammed for flood control in the 1960s, and it is now a [[List of Kansas state parks|state park]] that offers many recreational opportunities.  South of the city is the [[Konza Prairie]], a tallgrass [[prairie]] preserve owned by [[The Nature Conservancy]] and [[Kansas State University]].

====Earthquakes====
Kansas is not known for earthquake activity, but Manhattan is near the [[Nemaha Ridge]], a long structure bounded by several faults, and which is still active.<ref>{{cite journal|title=History of earthquakes in Kansas|author=Merriam, Daniel F.|journal=Bulletin of the Seismological Society of America|date=April 1956|volume=46|issue=2|pages=87–96|doi=10.1785/BSSA0460020087|bibcode=1956BuSSA..46...87M}}</ref> In particular, the [[Humboldt Fault]] Zone lies just {{convert|12|mi|km|0}} eastward of Tuttle Creek Reservoir.

On April 24, 1867, the [[1867 Manhattan earthquake]] struck Riley County. Measuring 5.1 on the [[Richter magnitude scale]], the earthquake's [[epicenter]] was by Manhattan. It remains the strongest earthquake to originate in Kansas, at an intensity of VII (''Very strong'') on the [[Mercalli intensity scale]], and felt across roughly {{convert|193051|sqmi|km2|0}}. It caused largely minor damage, reports of which were confined to Kansas, Iowa, and Missouri, according to the [[United States Geological Survey]].

Although Kansas is not seismically active, a strong earthquake could pose significant threats to the state. If an earthquake had occurred along the Nemaha Ridge prior to 2010, it could have destroyed the dam on Tuttle Creek Reservoir, releasing {{convert|300000|ft|m|0}} of water per second and flooding the nearby area, threatening roughly 13,000 people and 5,900 homes. A study in the 1980s found 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." To address this threat, the [[United States Army Corps of Engineers|Army Corps of Engineers]] completed a project in July 2010 that replaced the sand with more than 350 concrete walls and equipped the dam with sensors. Alarms are connected to these sensors, which would alert nearby citizens to the earthquake.<ref name=LJW>{{cite news|url=http://www2.ljworld.com/news/2008/may/02/shaking_kansas/|title=Earthquakes in Kansas a real threat|work=[[Lawrence Journal-World]]|author=Metz, Christine|date=May 2, 2008|access-date=February 11, 2010}}</ref>