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Centenary geologist tells Shreveport council recent tremors are shallow, minor and likely to continue
Summary
Dr. Scott Vetter, chair of geology at Centenary College, told the Shreveport City Council that a series of small, shallow earthquakes in the region are expected to continue but are unlikely to cause structural damage or loss of life.
Dr. Scott Vetter, chair of the Department of Geology at Centenary College, told the Shreveport City Council that the recent earthquakes felt around Shreveport were small, shallow events and posed little risk to structures or people.
“Less than a week ago… there was an earthquake about 6 kilometers southeast of Mooringsport, had a magnitude of 3… had a depth of about 5 kilometers,” Vetter said, describing the event and showing a map of reported felt locations. He added, “We’re not going to have a big earthquake. Basically, our earthquakes here in Louisiana are very shallow.”
Vetter told the council the region’s quakes are typically magnitude 3 or lower and are associated with shallow growth faults in sedimentary basins rather than major plate-boundary faults. He said instruments can detect many events that most people do not feel and that there has been no reported structural damage or loss of life associated with recent tremors.
The geologist addressed public concerns that hydraulic fracturing (fracking) was the primary cause. He said that while fracking can induce microseismic events, most induced earthquakes traced by scientists have been associated with deep disposal of wastewater from oil and gas operations, not the fracking process itself. Quoting a USGS review, he summarized: “Most of the induced earthquakes are due to deep disposal of this wastewater… fracking is a very small portion of it.”
Council members asked follow-up questions about groundwater and aquifers. Vetter said local aquifers are much shallower than the shallow earthquakes (roughly 3.1 miles or about 5 kilometers deep versus aquifers “at most a couple thousand feet”), and he said the small magnitude of recent events made any effect on aquifers “very slim.”
Vetter provided his presentation file to city staff and made himself available for further questions. He said the region should expect occasional small quakes but that they pose a low risk to public safety or infrastructure.
Ending: The council did not take formal action during the presentation. The briefing was presented to respond to constituent calls and to give councilmembers scientific context for public concerns about the recent tremors.
