TexNet - Earthquake Catalog - 2023

Health & Safety - Mining, Environmental, & Cybersecurity

TexNet is a statewide earthquake monitoring system and research program funded by the State of Texas and managed and operated by the Bureau of Economic Geology at The University of Texas at Austin. The Bureau is the State Geological Survey of Texas. The TexNet system has a network of permanently installed seismometers across the state, as well as an inventory of portable seismometers that are deployed on a temporary basis. TexNet’s role is to detect, locate, and report on earthquakes within the State of Texas. TexNet research includes analysis and reporting of earthquakes and their possible causes (whether naturally occurring or induced).

Does TexNet regulate industry activity?

No. TexNet does not have a regulatory role in the State of Texas.

How will TexNet use its earthquake data, and who will have access to it?

TexNet research builds on the existing foundation of data and knowledge to better understand earthquake patterns and potential in Texas. TexNet data and results are being incorporated into other geologic and engineering studies and made available to regulators, industry, academics, researchers, the national earthquake reporting system run by the United States Geological Survey (USGS), and the public.

What can I do to prepare my family and myself for possible earthquakes?

First, keep the risk in perspective. Small earthquakes may unnerve you, but they won’t hurt you. Larger earthquakes can be dangerous but are rarer. The biggest earthquakes are the rarest of all. Although no one can precisely predict the size, location, or timing of earthquakes, people can prepare for them.

Typically, people are injured during an earthquake when strong ground shaking damages the “built environment” (buildings, building contents, nonstructural elements like chimneys or water heaters, or infrastructure). One of the best ways to prepare for an earthquake is to improve the safety of the built environment. You can also practice what to do during an earthquake by joining millions of other people in the annual ShakeOut Earthquake Drill: https://www.shakeout.org.

For more information:

 https://www.earthquakecountry.org/sevensteps/   
https://www.ready.gov/earthquakes 
https://earthquake.usgs.gov/learn/preparedness.php

Do scientists want to know if I feel an earthquake?

Yes. Gathering data on what people feel during earthquakes is important for assessing local earthquake trends and behavior.
Please visit the USGS “Did You Feel It?” website to provide information on earthquakes that you have experienced: 
https://earthquake.usgs.gov/data/dyfi/

What is the difference between naturally occurring and induced earthquakes?

Most naturally occurring earthquakes are related to the movement of the tectonic plates of Earth’s crust. Such earthquakes are called tectonic earthquakes. Induced earthquakes are those caused by human activity. The most common causes of induced earthquakes include geothermal energy extraction, underground mining, oil and gas withdrawal, water disposal by injection, and the filling of surface-water reservoirs behind dams. Induced earthquakes are sometimes called triggered earthquakes.

For more information: 

https://www.sciencedaily.com/terms/earthquake.htm

Does Texas experience naturally occurring and induced earthquakes?

Yes. Researchers Frohlich and Davis (2002, Texas Earthquakes, University of Texas Press) looked at historical records from newspapers and technical reports and found accounts of naturally occurring earthquakes in Texas, up to and above magnitude 5.0, as far back as 1925. In Texas, where earthquakes have been reported for 170 years, the biggest recorded earthquake had a magnitude of about 6.0; it occurred in 1931 near the town of Valentine in West Texas. This is one of five earthquakes above magnitude 5.0 that have been recorded in our state. The oldest reported felt earthquake event occurred on May 1, 1873, in Manor, near Austin.

Regarding induced earthquakes, USGS data show an increase since 2008 in the number of earthquakes in Texas exceeding magnitude 2.5. This increase corresponds timewise to an increase in the rate of wastewater disposal in geologic formations in the state. To understand if and how wastewater disposal causes earthquakes, new data and advanced geologic analysis—part of TexNet’s mission—are required.

Is there any way to tell if an earthquake was induced?

It is often difficult to definitively determine whether a specific earthquake was induced. Experts look at when the earthquake occurs, its depth, its magnitude, the previous patterns of earthquakes in that area, and other factors that are influenced by human activities.

Can hydraulic fracturing cause earthquakes?

The hydraulic fracturing process causes tiny earthquakes as it cracks the nearby rock. In certain circumstances, the cracks can contact a pre-existing fault and trigger additional motion. In such cases reported in British Columbia, Ohio, and Oklahoma, the earthquake ceased after the fracturing process was complete, and almost all events were too small to be felt.

What are the hypocenter and epicenter of an earthquake?

The hypocenter (or focus) is the point within the earth where the fault first begins to slip. The epicenter, on the other hand, is the point directly above the hypocenter on the ground surface. The TexNet webpage shows the epicenter location and the depth to hypocenter. The depth is provided in terms of two reference points: relative to ground surface and relative to mean sea level.

https://earthquake.usgs.gov/learn/glossary/?term=hypocenter

https://earthquake.usgs.gov/learn/glossary/?term=epicenter

What is the ground motion of an earthquake?

Ground motion is the shaking caused by seismic waves. Special instruments called seismometers measure ground motion, recording the actual ground-motion characteristics that affect structures and people. Ground motion and magnitude are related, but in very complex ways that depend on geology, distance from the earthquake, and characteristics of the earthquake.

Why are so many earthquakes showing up on the TexNet website?

With the installation of more than 50 new seismometers across the state, Texas has increased its ability to detect earthquakes, including very small earthquakes that are not felt at the surface. In nature, far more small earthquakes than large ones occur. Because much smaller events can now be detected, more earthquakes will be recorded.

Do we really need to spend public money monitoring earthquakes in Texas?

Experience has repeatedly shown that proactive responses and sensible management decisions can address earthquake-activity issues before they become a significant problem. By analyzing data from the monitoring network and placing those data into a geologic context, TexNet provides an independent, comprehensive investigative approach that:

1) will better inform the public, industry, and regulators;
2) can be used by officials and citizens to make better decisions; and
3) can help mitigate and reduce effects of future earthquakes through improved knowledge and operational and regulatory practices.