Nemaha Ridge

Structures of Kansas showing the Nemaha Uplift/Ridge

The Nemaha Ridge (also called the Nemaha Uplift) is located in the Central United States. It is a buried structural zone associated with a granite high in the Pre-Cambrian basement that extends from approximately Omaha, Nebraska to Oklahoma City, Oklahoma. The ridge is associated with the seismically active Humboldt Fault zone. It is also associated with the Proterozoic Midcontinent Rift System, which extends into northern Kansas about fifty miles west of the Nemaha.^[1]

Along the Nemaha Ridge is a series of faults referred to as the "Nemaha Fault Zone".^[1] The long term uplift along the ridge has been attributed to isostatic uplift due to the anomalously thick crust adjacent to the Midcontinent Rift.^[2]

References

1 2 Kansas Geological Survey, Current Research in Earth Sciences, Bulletin 250, part 1 "Review of the Nemaha Ridge: A New Look at an Old Structure"
↑ Gao, Stephen S., et al., Old Rifts Never Die: Crustal Thickening Across the Midcontinent Rift and Its Possible Role in Post-Rifting Tectonics, Structure and Tectonics of the Midcontinent, North America, GSA 2002 Denver Annual Meeting

Significant seismically active faults of North America

North America
(crosses national borders)

Alaska-Aleutian megathrust (US-RU)
Basin and Range Province (US-MX)
Cascadia subduction zone (US-CA)
Clarendon-Linden fault system (US-CA)
Denali Fault (US-CA)
Northern Cordilleran Volcanic Province (CA-US)
Puget Sound faults (US-CA)
Rio Grande rift (US-MX)
San Andreas Fault (US-MX)
Southern Great Lakes Seismic Zone (US-CA)
Tintina Fault (US-CA)

Canada

United States

Washington and Oregon	Brothers Fault Zone Olympic-Wallowa Lineament Puget Sound (Seattle Fault, Tacoma Fault) Walker Lane

California	Calaveras Fault Garlock Fault Hayward Fault Zone Mendocino Fracture Zone Newport–Inglewood Fault Puente Hills Fault Rose Canyon Fault San Jacinto Fault Zone (Elsinore Fault Zone)

Great Basin	Independence Valley fault system Moab Fault Teton Fault Wasatch Fault

Great Plains	Central Oklahoma Fault Zone Humboldt Fault Long Point–Eureka Heights fault system Nemaha Fault Zone Wilzetta Fault

Midwest	Marianna Fault New Madrid Seismic Zone Sandwich Fault Zone Wabash Valley Seismic Zone

Appalachian Mountains and Atlantic Coast	Aiken-Augusta Fault Eastern Tennessee Seismic Zone Middleton Place-Summerville Seismic Zone (Woodstock Fault) Northern Appalachians Seismic Zone Ramapo Fault Virginia Seismic Zone

Caribbean & Mexico

Cayman Trough
Chixoy-Polochic Fault
Enriquillo–Plantain Garden fault zone (Cuba)
Gulf of California Rift Zone
Lesser Antilles subduction zone
Middle America Trench (Central America)
Motagua Fault (Central America)
Pedro Miguel Fault
Puerto Rico Trench

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