UIS Commission on Karst Hydrogeology and Speleogenesis
Schindel, Geary M.
  PDF: /pdf/seka_pdf9591.pdf


The Edwards Aquifer is a large karst aquifer located in south-central Texas USA. The Index Well J-17, in which water levels in the aquifer are continuously monitored since 1934, detected distinctly the March 11, 2011 Honshu, Japan earthquake (9.0 magnitude). The Edwards Aquifer fluctuated approximately 0.3 meters (1 foot) during the initial response and continued to oscillate for approximately two hours after the event.