Eight earthquakes rattle Oklahoma in less than 24 hours, geologists say

Seven earthquakes rumbled in Oklahoma between Sunday afternoon and Monday morning, according to the United States Geological Survey.

The first earthquake shook just before 1 p.m. about 4 miles east of Renfrow near the Kansas state line, data show. The USGS did not receive reports of anyone feeling the 1.7 magnitude temblor.

The next and largest earthquake of the group — magnitude 2.9 — rattled at 4:26 p.m. roughly 4 miles north of Ames, the USGS reported. Ames is about 70 miles southwest of Renfrow.

The USGS received one report of shaking that was categorized as II on the Modified Mercalli Intensity Scale; or weak shaking. Typically, weak shaking does not produce damage. The Modified Mercalli Intensity Scale measures the intensity of an earthquake and is determined by how the temblor is felt by people and by observed structural damage, according to the USGS.

The next temblor hit several minutes later at 4:50 p.m., also near Ames, USGS reported. The earthquake measured magnitude 1.8, according to data.

The fourth earthquake was magnitude 1.7 and rumbled at 8:33 p.m., about 2-and-a-half miles north of Drummond, the USGS reported. Drummond is about 13 miles east of Ames.

Another 1.7 magnitude temblor shook about 3 miles north of Ames at 8:46 p.m., followed by a sixth quake — also magnitude 1.7 — also near Ames at 9:43 p.m., according to the USGS.

The seventh earthquake was magnitude 1.9 and shook about 7 miles northwest of Longdale at roughly 12:30 a.m. Monday, the USGS reported.

An eighth temblor rattled at 6:03 a.m. about 3 miles north of Ames, according to the USGS. It was measured as magnitude 1.3, data say.

Magnitude measures the energy released at the source of an earthquake and replaced the old Richter scale, the USGS reported.

Most of these earthquakes were characterized as a I on the Modified Mercalli Intensity Scale, meaning they likely were not felt.

Correction: An earlier version of this story indicated that there were eight earthquakes in less than 12 hours. USGS data shows that there were seven earthquakes in less than 12 hours and eight in less than 24 hours.

This story was originally published June 8, 2020 at 8:11 AM.