Item talk:Q228393

{

 "@context": "http://schema.org/",
 "@type": "WebPage",
 "additionalType": "Activity",
 "url": "https://www.usgs.gov/mission-areas/water-resources/science/groundwater-level-response-virginia-earthquake-august-23-2011",
 "headline": "Groundwater-Level Response to Virginia Earthquake, August 23, 2011",
 "datePublished": "February 23, 2019",
 "author": [
   {
     "@type": "Person",
     "name": "Rodney A Sheets, Jr.",
     "url": "https://www.usgs.gov/staff-profiles/rodney-a-sheets",
     "identifier": {
       "@type": "PropertyValue",
       "propertyID": "orcid",
       "value": "0000-0003-0063-4903"
     }
   }
 ],
 "description": [
   {
     "@type": "TextObject",
     "text": "Step changes in groundwater levels occur 'near field' of an earthquake because the earthquake subjects the earth's crust, including its aquifer systems, to stress and permanent strain (deformation). This deformation process results in altered fluid pressure within the aquifer systems, and consequently, a steplike change in water level would be expected. Changes can be up or down, because the stress and strain effects on the system vary. For upward steps in shallow wells, compaction of overlying sediments may raise the groundwater level. Alternately, in a fractured rock aquifer, the fractures providing water to the well may be widened, unclogged, or sealed by the wave train of an earthquake. New water-bearing fractures may even be created. Water levels in these systems can permanently increase or decrease as a result."
   },
   {
     "@type": "TextObject",
     "text": "Slide Show of Selected Hydrographs"
   },
   {
     "@type": "TextObject",
     "text": "How do Earthquakes Affect Groundwater Levels?"
   },
   {
     "@type": "TextObject",
     "text": "Groundwater-level responses to earthquakes have been investigated for decades, and have been documented close to and far from earthquake epicenters. The most common groundwater-level response is a water-level oscillation. This occurs frequently, but often is not recorded because water-level measurements typically are not recorded frequently enough with today\u2019s electronic instrumentation to record the water-level response. An instantaneous water-level offset, or step, is more commonly recorded. These step changes can be large enough to make a well flow at land surface, or to cause a well to go dry near an earthquake. Typically, however, the water-level changes are several feet or less. Recovery to the pre-earthquake water level can be nearly instantaneous, or it may take as long as days or months, or may not recover at all."
   },
   {
     "@type": "TextObject",
     "text": "A magnitude 5.8 (Mw) earthquake occurred at 1:51 pm EDT (17:51 UTC) on August 23, 2011, at a depth of about 3.7 miles (6 kilometers) beneath the town of Mineral, Virginia, located approximately 27 miles (45 kilometers) east of Charlottesville. The event is among the largest earthquakes recorded in the eastern United States."
   },
   {
     "@type": "TextObject",
     "text": "Groundwater-level responses most often occur as the earthquake\u2019s seismic wave train arrives (coseismic), though responses have been observed after the wave train passes (postseismic); scientists also are investigating water-level changes observed before an earthquake (preseismic), though research is needed to explain these phenomena."
   },
   {
     "@type": "TextObject",
     "text": "The six hydrographs below present groundwater levels measured in selected wells monitored by the USGS (all data are from the National Water Information System). These graphs were selected as examples of locations where measured groundwater levels responded to the August 23, 2011, Virginia earthquake. The red arrow indicates the approximate time of the mainshock of the earthquake near Mineral, Virginia."
   },
   {
     "@type": "TextObject",
     "text": "Other Information"
   }
 ],
 "funder": {
   "@type": "Organization",
   "name": "Water Resources Mission Area",
   "url": "https://www.usgs.gov/mission-areas/water-resources"
 },
 "about": [
   {
     "@type": "Thing",
     "name": "Energy"
   },
   {
     "@type": "Thing",
     "name": "Geology"
   },
   {
     "@type": "Thing",
     "name": "Hazard and Event Monitoring"
   },
   {
     "@type": "Thing",
     "name": "Hazards (Floods, Droughts, Hurricanes, etc.)"
   },
   {
     "@type": "Thing",
     "name": "Science Technology"
   },
   {
     "@type": "Thing",
     "name": "Environmental Health"
   },
   {
     "@type": "Thing",
     "name": "Measuring and Monitoring Water"
   },
   {
     "@type": "Thing",
     "name": "Groundwater, Aquifers, Wells, and Springs"
   },
   {
     "@type": "Thing",
     "name": "Types of Water"
   },
   {
     "@type": "Thing",
     "name": "Common Water Issues"
   },
   {
     "@type": "Thing",
     "name": "Water"
   },
   {
     "@type": "Thing",
     "name": "Information Systems"
   },
   {
     "@type": "Thing",
     "name": "Groundwater Monitoring"
   },
   {
     "@type": "Thing",
     "name": "Methods and Analysis"
   }
 ]

}