OKLAHOMA CITY (AP) -- Oklahoma's largest recorded earthquake affected geological structures both above and below ground, but experts caution there still is much that scientists don't know the 5.8-magnitude temblor that struck last year near Pawnee.
Ten separate academic studies into the Sept. 3 quake will be included in an upcoming issue of Seismological Research Letters, an internationally recognized peer-reviewed journal.
Thousands of earthquakes have been recorded in Oklahoma in recent years, with many linked to the underground injection of wastewater from oil and natural gas production
Oklahoma Geological Survey Director Jeremy Boak says the number of quakes larger than 4.0 magnitude has dropped dramatically so far this year, but it's still not clear what caused several large quakes last year that were above 5.0 magnitude.
Copyright 2017 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.