Significant earthquakes are rare in Louisiana. The state’s geological setting results in a unique seismic profile, characterized by infrequent, minor events. This explains why major seismic activity is uncommon within its borders.
The Latest Recorded Seismic Event
The most recent verifiable earthquake within Louisiana’s borders was a magnitude 3.5 tremor that occurred on Saturday, January 18, 2025, approximately 2 kilometers west-northwest of Mooringsport. Another notable, slightly earlier event was a 3.1 magnitude earthquake that struck 7 kilometers south-southwest of Mooringsport late on Friday, December 20, 2024, at a depth of 5 kilometers.
While these events were felt by some residents in surrounding areas, they caused no significant damage or injuries. Several other small tremors, including a 3.0 magnitude quake on January 6, 2025, have also been reported in the northwest region of the state around Mooringsport and Oil City in late 2024 and early 2025.
Louisiana’s Geological Stability
Louisiana is situated within the Gulf Coast Basin, a geological zone recognized for its low seismic activity. Its location far from active tectonic plate boundaries is a primary reason for the rarity of large earthquakes. Unlike regions at plate margins where significant crustal movements occur, Louisiana rests on a stable continental platform.
While major fault lines that cause large-scale earthquakes are largely absent, Louisiana does have shallow “growth faults,” particularly in its northwestern and southern areas. These faults are associated with the immense weight of sediments deposited by the Mississippi River over geological time, causing the crust to gradually sag in a process known as the Gulf Geosyncline. Movement along these growth faults is typically slow and gradual (creep), rather than sudden, energy-releasing ruptures that generate strong earthquakes. This geological characteristic contributes to the state’s very low classification for earthquake hazard, with a less than 2% chance of damaging shaking over a 50-year period.
Historical Patterns of Seismic Activity
Despite its generally stable geological setting, Louisiana has experienced occasional minor tremors throughout its recorded history. These events have typically been infrequent and of low magnitude. Since 1900, the state has recorded over 100 earthquakes with magnitudes above 2.0, with most being below magnitude 3.0.
The largest earthquake ever recorded within Louisiana occurred in 2006, registering a magnitude of 5.3 approximately 157 kilometers south of Grand Isle. Earlier notable historical events include a 4.2 magnitude quake near Donaldsonville in 1930, which was felt in New Orleans and caused objects to fall. Other minor tremors, such as a 3.8 magnitude event in the Grand Chenier and Creole area in 1959 and another 3.8 magnitude quake near Lake Charles in 1983, also form part of Louisiana’s seismic record.
A series of earthquakes, ranging from magnitude 3.0 to 4.0, occurred between April and August 1964 near the Texas-Louisiana border, coinciding with the filling of the Sam Rayburn Reservoir and construction of the Toledo Bend Dam. Louisiana can also feel the effects of distant earthquakes, such as those from the New Madrid Seismic Zone, which typically manifest as minor tremors rather than damaging ground shaking within the state.
Understanding Minor Tremors and Induced Seismicity
Minor tremors are the most common form of seismic activity experienced in Louisiana. These small quakes are often barely perceptible, or may only cause slight vibrations or rattling. They are distinct from larger, more damaging earthquakes in seismically active regions.
Human activities can also contribute to seismic events through induced seismicity, particularly related to wastewater injection. In Louisiana, large volumes of water from oil and gas operations are frequently disposed of by injecting them into deep underground wells. While induced seismicity is a more significant concern in other states like Oklahoma and Texas, it has been linked to increased minor tremors in specific areas of Louisiana. For instance, recent tremors in northwest Louisiana have been attributed to fluid injection from oil and gas operations, which can increase underground pressure and activate existing faults.