OROVILLE (KPIX 5) — As the main spillway failed at Oroville dam last February, researchers at the U.S. Geological Survey were focused on another event happening at the dam that couldn’t be seen or heard without special equipment.
USGS research geophysicist Ole Kaven said they noticed two earthquakes: one a magnitude 1.0 and the other 0.8.
“We were wondering what was going on,” said Kaven.
Kaven and other scientists took a closer look, going back to records as far as 1993.
“And found close to 20,000 of these tiny events, more or less in the same location,” he said.
But now the questions were: what was causing them? Could it be the dam itself? And could the quakes be the cause of the spillway?