You might tremor to know how many earthquakes and their magnitude have impacted our state of Texas. The earliest recorded earthquake in Texas was on February 14, 1847, located in Sequin, Texas, with a magnitude of 3.6. Since then, over 200 earthquakes over 3.0 on the Richter Scale have been documented. Shockingly there have been six earthquakes between 5.0 and 6.0, all located with an epicenter in West Texas or the Texas Panhandle. The 5.0 Mentone Texas quake happened on March 26, 2020. People felt tremors as far as away as the City of El Paso.
The strongest earthquake reported in Texas was the 6.0 earthquake with an epicenter in Valentine, Texas (Jeff Davis County) on August 16, 1931. Newspapers reported this geological phenome was felt as far east as Taylor, Texas (Williamson County just north of Austin, Texas). An alarming seven tremors shook the area that day, some lasting as long as 72 seconds. The series of quakes started early morning and continued to the early afternoon. The earthquake was felt as far south as San Antonio. Comanche Springs, which is located 100 miles northeast, reported that the water out of the springs, 60 million gallons at the time, was muddy for an hour after the quakes. Damage to buildings and chimneys was reported in Valentine. Sources say that almost all the buildings in the area were damaged. As the buildings continued to sway, the town citizens took refuge outside and slept out in the open that night. This earthquake was even felt in Carlsbad, New Mexico, and affected the Caverns.
The second most robust earthquake was a 5.7 on April 14, 1995, with an epicenter in Alpine in Brewster County. Some of the impacts are reports of water main damage, fire hydrants, cracked walls, breaking gas mains, creating fires, and causing landslides. The area was stunned with 12 minutes of aftershocks.
To round out the subsequent three strongest earthquakes in Texas include
|Rank in Texas||Year||Day||Month||Time||Magnitude||County||City|
Jeff Davis and Potter counties have experienced 13 reported more significant magnitude earthquakes. Winkler county has experienced 16 reported earthquakes within 3 to 4 magnitude. This is due to the fault lines for the Rio Grande Rift belt, the Panhandle belt, the Ouachita belt located in West Texas, and the Panhandle areas. Another tectonic fault line is near the Coastal Plain.
Large earthquakes have also impacted Texas from Mexico, such as September 19, 1985, which had a magnitude of 8.0. This earthquake centered in Mexico City was felt as far north as Houston. Some Texas cities experienced broken water pipes and other damage.
While there are earthquakes almost every year in Texas detected by seismograms, these earthquakes are small in magnitude. As engineers and readied citizens, it is essential to know your risk in where you are designing and living on earthquakes. An easy way to find out the history of earthquakes in your area is to visit http://www-udc.ig.utexas.edu/external/TXEQ/index.html. This site provides an easy way to look at recorded earthquakes by county. This link is the Texas Earthquakes site by the Institute for Geophysics at the Jackson School of Geosciences at the University of Texas at Austin. The site has resources that you can also study further about being ready to protect your family and other information. Another site to look at would be the USGS Earthquake Hazards for the latest earthquakes. https://www.usgs.gov/natural-hazards/earthquake-hazards/earthquakes
Quake Stricken in Texas
By Melinda Luna PE | ASCE Texas Section History & Heritage Committee Chair
This is a three-part series on the Rehabilitation of the Waco Suspension Bridge. Parts 2 and 3 will be added in during future issues as the project progresses. Bookmark this article and set a reminder to check back for the conclusion of this insightful series.
〰 Part 1 〰
The team of Modjeski and Masters, Structural Technologies, Sparks Engineering Inc. (Engineer of Record) and Gibson & Associates (General Contractor) with the City of Waco have undertaken the project of rehabilitation of the Waco Suspension Bridge. Tom Balk LA, the Program Manager for Waco’s Park Planning and Assets, describes the venture as a “very exciting project for the City of Waco.” He goes on to say, “this remarkable bridge has been foundational in our city’s development and is a key piece of our history.”
The Waco Suspension Bridge was originally built, completed, and officially opened in 1870. Before the bridge, people crossing the Brazos River as part of the Chisholm Trail would use a ferry. A group in Waco saw the need to form a team and obtain a charter to build the bridge. The group, led by Thomas M. Griffith, an engineer who had worked for John A. Roebling’s Sons Company (built the Brooklyn Bridge in New York City), hired Waco Bridge Company to complete the project. The bridge has already been rehabilitated once in 1914 after a flood but its cables have not been replaced since then.
The bridge spans the Brazos River at Bridge Street in Waco, McLennan County, Texas and is now a walking bridge, a favorite for prom photos and tourists.
The current group of engineers and contractors is working to restore the bridge and ensure the bridge is around for another generation of Texans. We contacted the City of Waco and Patrick Sparks PE of Sparks Engineering to gain deeper insight into this great project with an estimated construction costs of $12.4 million.
What has been the biggest challenge so far?
Sparks: One of the biggest challenges was putting in the temporary piers in the main river channel to support the stiffening trusses. This step will allow the bridge to be supported while the cables are de-tensioned and removed.
What is the progress of the project so far?
Sparks: The bridge is fully supported by temporary piles in the river, and the suspender rods are being removed. Shortly, the cable de-tensioning will begin. Modjeski team began working on the project in the Summer of 2020.
When can we expect the project to be completed considering the progress?
Sparks: It looks like we are on track for Spring of 2022.
What is the plan to open the bridge?
Sparks: It is too early to know what we are going to be dealing with as far as the current situation. Everyone is excited about the project and there will be something planned to celebrate the project. The City of Waco says that planning will start toward the end of this year (2021)
Join us for Part 2 of this series in a future issue of the Texas Civil Engineer (TCE). If you have a question on this project for Mr. Sparks, please send it to Melinda Luna PE at [email protected].
Photos Credit: Waco Suspension Bridge, Spanning Brazos River at Bridge Street, Waco, McLennan County, TX (Library of Congress Prints and Photographs Division, http://hdl.loc.gov/loc.pnp/pp.print)