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flows. According to the United States Geological Survey (USGS), the most common type of <br />landslides in Minnesota are shallow slope failures that occur during heavy rain. <br /> Land subsidence: The gradual sinking or settling of the earth's surface, often due to the <br />compaction of underground layers of soil, sediment, or rock. This phenomenon can occur <br />naturally or be exacerbated by human activities such as groundwater extraction, oil and gas <br />extraction, mining, or the drainage of organic soils. Examples of land subsidence include <br />sinkholes and soil compaction. According to the USGS, more than 80% of the identified <br />subsidence in the United States is a consequence of human impact on subsurface water and is <br />an often-overlooked environmental consequence of land and water-use practices. Increasing <br />development can exacerbate subsidence problems and initiate new ones. <br />3.9.2 LOCATION <br />Parts of Ramsey County sit on a thick layer of limestone rock that is riddled with small holes and caves, <br />known as karst topography. Its large rivers and hills also create many slopes and cliffs. Heavy surface <br />rains may cause karst landscapes to fail causing landslides or sinkholes. Figure 9 shows karst distribution <br />throughout Minnesota. <br />Ramsey County | Multi-Jurisdiction Hazard Mitigation Plan 58 <br />Qbhf!328!pg!488 <br /> <br />