Q: Are there earthquakes in Texas?
A: Yes. In historical times no earthquake with magnitude larger than about 6 has occurred in Texas. However, seismographs near El Paso record small earthquakes with magnitude of 2 or smaller every few days. Nearly every year earthquakes large enough to be felt by ordinary citizens occur somewhere in Texas.
Locations of earthquakes that have occurred in Texas, or that were felt within Texas. Numbers denote year of occurrence of very recent or very significant Texas earthquakes.
Locations of earthquakes in the Texas region between 01 January 2005 through 05 July 2009.
Q: What is the largest earthquake in Texas in recorded history?
A: The largest earthquake in Texas history had a magnitude of about 6.0 and occurred on 16 August 1931 near the town of Valentine, 220 km southeast of El Paso. It caused severe damage to adobe and brick structures in Valentine, and was felt by Texans as far away as Dallas. Texas' second largest earthquake occurred on 14 April 1995, also in west Texas. It had a magnitude of 5.8, and was felt in Austin.
Q: What is the highest death toll from a historical Texas earthquake?
A: Only one Texas earthquake ever took a human life, and this wasn't in Texas. On 6 March 1923 an earthquake with magnitude of 4.7 occurred near El Paso and Juarez. Juan Ortiz, a Mexican tenant farmer who lived in Mexico six miles from Juarez, suffocated when his adobe house caved in during the quake.
Q: What was the most damaging earthquake in Texas history?
A: No Texas earthquake has caused much damage as compared to some earthquakes in other states or throughout the world. The most damaging was the 16 August 1931 earthquake in Valentine, Texas, where "all but frame houses were badly damaged, and all brick chimneys toppled over....The schoolhouse, consisting of one section built of cement blocks and another of brick....required practically complete rebuilding."
|1991 July 20||3.6||Falls City|
|1993 April 9||4.3||Fashing||Slight damage, some aftershocks|
|1995 April 14||5.7||Alpine||Some damage, some aftershocks|
|1997 March 24||3.8||Alice||Felt In Alice|
|1997 May 31||3.4||Commerce||Felt In Commerce|
|2008 October 30<||3.0||Dallas-Fort Worth||Felt in Bedford, Euless, Fort Worth, Irving, and Dallas. Several aftershocks occurred|
|2009 May 16||3.0||Dallas-Fort Worth||Felt widely in the Dallas-Ft Worth Area, at Bedford, Colleyville, Dallas, Euless, Grand Prarie, Grapevine, Hurst, Irving and Roanoke.|
|2010 April 25||3.9||Alice|
2011 Sep 11
|2011 Oct 20||4.8||Fashing|
|2012 May 17||4.8||Timpson|
|2013 Jan 25||4.1||Timpson|
|2013 Sep 2||4.3||Timpson|
Q: Has an earthquake occurred in Austin in historic times?
A: On 9 October 1902 an earthquake with magnitude about 3.9 occurred about 15 km south of Austin near the town of Creedmoor; this event was felt in Austin. However, there were no felt reports in Austin from an earthquake with magnitude of 3.1 that occurred in Manor (15 km east of Austin) on 1 May 1873. Every few years Austin residents in tall buildings may feel the effects of large, distant earthquakes, such as the 19 September 1985 Michoacan, Mexico earthquake, and the 14 April 1995 earthquake in west Texas.
Q: What sort of earthquakes should we expect from the Balcones Fault?
A: Probably none. The Balcones Fault is the boundary between the central Texas hill country to the west of Austin and the flatter plains regions to the east. About 10 million years ago this was an active fault, but it is not active any longer. A "fault" simply represents a boundary between two sections of the earth's crust that move or slip relative to one another. When slip is ongoing, the fault is active. After the slip stops, the fault remains. Thus, in Texas and elsewhere the land is riddled with faults which no longer present any significant earthquake risk.
Q: Where can I get a map showing the geologic faults of Texas?
A: The University of Texas at Austin Walter Geology Library has a geologic map of Texas which has the major faults on it (but not all the faults). You might also check out the Bureau of Economic Geology.
Q: Have earthquakes occurred in Houston in historic times?
A: No. The closest earthquake occurred on 8 May 1910 near Hempstead, Texas, about 70 km northwest of Houston. This earthquake had a magnitude of about 3.8, and was felt by individuals within about 30 km of Hempstead, but not in Houston. Of course, Houston residents in tall buildings may occasionally feel large very distant earthquakes that occur in Mexico or western Texas.
Near Houston there may be examples of faults which are active, but which don't have any earthquakes. Land in some communities southeast of Houston such as Clear Lake and Dickenson is sinking because water has been pumped out from the ground for many years; this sinking may be associated with slip along faults. However, when such slip is a slow or continuous "creep," it isn't an earthquake. To cause an earthquake the faults need to "stick" then slip suddenly enough to radiate seismic waves.
Q: Have earthquakes occurred in Dallas-Fort Worth in historic times?
A: Yes. On October 30, 2008, an earthquake was felt in the Dallas-Fort Worth Area. Since May 16, 2009, several earthquakes have been felt in the Dallas-Fort Worth Area.Q: Have earthquakes occurred in San Antonio in historic times?
A: No. However, since 1973 a number of earthquakes have occurred near the cities of Fashing and Pleasanton about 50 km south of San Antonio. The largest of these had a magnitude of 4.8 and occurred on 20 October 2011 in Fashing. Of course, San Antonio residents in tall building may occasionally feel effects of very distant earthquakes in Mexico or west Texas.
Figure 2, an isoseismal map of the cities of Fashing and Pleasanton.
Q: Have earthquakes occurred in Corpus Christi in historic times?
A: On 24 March 1997 and on 25 April 2010 two very similar earthquakes with magnitude 3.9 shook Alice, Texas, a community situated about 60 km west of Corpus Christi. These are the only known earthquakes in this local area in historic times. Although the Corpus Christi Caller Times reported that the 1997 quake was felt in Corpus Christi, interviews by a team of UT students determined that this was erroneous; apparently reporters were confused by reports of people "near" Corpus (but actually in Alice) feeling the quake. Felt report studies for both quakes determined that the entire felt areas were about 900 km2; the highest Mercalli intensities of about VI were from a sparsely populated region about 10-15 km ESE of Alice, Texas. This region lies along the Vicksburg fault zone that runs nearly parallel to the Gulf coast and is within a few kilometers of the currently producing Stratton oil field. Although this location suggests that these earthquakes may have been triggered by hydrocarbon withdrawal, another likely possibility is that they have a tectonic origin and fall within a band of weak, natural seismic activity occurring inland from the Gulf coast eastward to the Texas-Louisiana border.
Q: Does drilling for oil and gas cause or trigger earthquakes?
A: Drilling itself never causes earthquakes, but some quakes are caused by various activities associated with petroleum production.Research carried out by UTIG scientists suggests that earthquakes in some parts of Texas may be induced by the pumping of fluids at oil and gas fields, or by the injection of fluids, either to enhance production or to dispose of fluid wastes, such as flowback brines from hydrofracturing operations. The earthquakes in the Fashing-Pleasanton area southeast of San Antonio are almost certainly caused by or triggered by pumping. Earthquakes near Snyder, Texas, appear to be caused by injection to enhance production; earthquakes near Dallas-Fort Worth and Timpson, Texas, seem to be triggered by fluid waste disposal operations.
Q: If pumping oil and gas cause earthquakes, is it safe to continue pumping?
A: Yes, it is usually safe. Earthquakes induced by the injection or pumping of fluids from wells are generally very small; most have magnitudes of 3 or less. Moreover, while tens of thousands of oil and gas wells exist in Texas, only a few fields show any evidence that oil and gas pumping induces earthquakes. However, a few apparently induced or triggered earthquakes in Texas have had magnitudes of 4.5-4.8; in urban areas such events pose a concern.