Earthquakes

Earthquake hazard map
Earthquake hazard maps show the probability that ground shaking will exceed a certain level over a 50-year period. The low-hazard areas have a 2% chance of exceeding a designated low level of shaking and the high-hazard areas have a 2% chance of topping a much greater level (modified from USGS seismic hazard maps and data, 2014).

 

Most movement in Earth's crust, known as seismicity, occurs when stress causes a fault or faults in subsurface rocks to slip and release enough energy to generate tremors. The vast majority of earthquakes are instigated naturally where Earth's tectonic plates interact. Away from plate boundaries, earthquakes are most often triggered when geological processes, such as the deposition and erosion of surface rock, alter the balance of opposing stresses on subsurface rocks.

Many Kansans have never felt so much as a tremor, but the state has a long history of felt earthquakes. The most powerful one documented, centered near Wamego east of Manhattan in 1867, caused moderate damage. Beginning in 2013, the state saw an increase in seismic activity, particularly in the south-central part of the state. This increased shaking raised questions about whether human activity, or induced seismicity, was to blame.

KGS scientists monitor and document seismic activity in Kansas. In relation to the potential for induced seismicity, scientists and others have developed geologically based approaches to identify areas at higher risk and recommendations to help prevent induced seismicity related to oil and gas operations.

 

 

Resources

 

Earthquake Highlights newsletter

Earthquakes: Kansas Geological Survey Public Information Circular 3

Induced Seismicity: The Potential for Triggered Earthquakes in Kansas: Kansas Geological Survey Public Information Circular 36

Kansas Earthquakes

Resources on induced seismicity

Seismology and Its Applications in Kansas: Kansas Geological Survey Public Information Circular 37, 2014, 6 p.