Update: Six earthquakes of magnitude 2.5 or larger have been recorded in Oklahoma on Saturday, according to the U.S. Geological Society. Today's quakes so far are:
- 2.5 magnitude at 2:43 p.m. Saturday about 1 miles ENE of Luther
- 2.7 magnitude at 1:42 p.m. Saturday about 17 miles east of Cherokee
- 2.6 magnitude at 8:04 a.m. Saturday about 8 miles NNW of Medford
- 2.6 magnitude at 7:21 a.m. Saturday about 6 miles NNW of Pawnee
- 2.7 magnitude at 5 a.m. Saturday about 8 miles NNW of Medford
- 2.8 magnitude at 3:22 a.m. Saturday about 9 miles NE of Cherokee
Three earthquakes of 3.0 magnitude or greater shook an area just northwest of Medford in Grant County within a 15-minute time period Thursday evening.
The first and biggest of the three, a 4.1 magnitude temblor, hit at 4:40 p.m. and could be felt as far as the Tulsa area to the east and Wichita, Kansas, to the north, according to the U.S. Geological Survey.
The measurement initially went out as a 4.6 magnitude quake but was quickly amended to 4.1 on the Geological Survey's website.
Two more earthquakes followed from the same area between 8 and 9 miles northwest of Medford. A 3.1 magnitude quake hit at 4:53 p.m. Friday, followed by a 3.9 quake two minutes later.
About 45 miles to the southwest near Helena, another quake erupted at 5:09 p.m. Friday, this time with a 3.3 magnitude. The quake was recorded about 7 miles northwest of Helena.
The Oklahoma Corporation Commission announced Friday plans to shut off four disposal wells within 3 miles of the earthquake activity near Crescent on Thursday. Two quakes were recorded, one of which was a magnitude 4.0.
The plan also called for a 50 percent volume reduction at seven Arbuckle disposal wells. Operators at other nearby wells also were put on notice to be prepared for possible changes in operation.
A 4.7 magnitude Oklahoma earthquake Thursday — the largest recorded in the state since 2011 — caused the Oklahoma Corporation Commission to shut down or reduce capacity at 25 disposal wells.
However, the state's quake activity has continued since that milestone temblor, according to the U.S. Geological Survey.
The USGS recorded 17 Oklahoma earthquakes since the 4.7, including a 4.0 magnitude near Crescent, and the 4.1 magnitude near Medford.
The quakes recorded as low as 2.6 magnitude (two Thursday near Cherokee and Medford), but also include six recorded earlier today:
- 2.7 magnitude 6:07 a.m. about 9 miles south-southwest of Cherokee
- 2.8 magnitude 9:42 a.m. about 15 miles north-northwest of Fairview
- 3.1 magnitude 3:11 p.m. about 15 miles east of Cherokee
- 3.2 magnitude 2:06 a.m. about 18 miles north-northwest of Fairview
- 3.5 magnitude 12:12 a.m. about 9 miles southwest of Cherokee
- 3.5 magnitude 5:22 a.m. about 9 miles southwest of Cherokee.
The Oklahoma Corporation Commission has said this year that 558 disposal wells are in an area of interest under scrutiny by scientists. That was an expansion from 347 wells first targeted earlier in the year.
World Staff Writer Stacy Ryburn contributed to this report.