An ODOT crew uses a boom to inspect underneath a bridge in southwestern Oklahoma.
ODOT Refines Department's
Post-Earthquake Response Guidelines
- The Oklahoma Department of Transportation has not identified any structural damage caused by earthquakes since 2011. However, many of the state's highway bridges are very old and have pre-existing damage. ODOT would close a bridge if it was deemed unsafe for any reason.
- Earthquakes have been primarily concentrated in north-central and central Oklahoma, with ODOT inspectors going more often to check bridges in these areas.
- ODOT designs bridges to national standards and they are built to withstand some amount of vibration due to traffic and to expand and contract due to weather changes.
Prior to April 2016, the department inspected bridges within a 5-mile radius after every 4.0-magnitude earthquake. Because no structural damage was ever found during the two years that the department inspected at this level and after scientific analysis and recommendations from its consultant, ODOT changed its inspection procedure to the following:
- 4.7 to 4.8 magnitude — 5-mile inspection radius;
- 4.9 to 5.3 magnitude — 15-mile inspection radius;
- 5.4 to 5.8 magnitude — 30-mile inspection radius;
- 5.9 to 6.2 magnitude — 60-mile inspection radius; and
- 6.3-plus magnitude — 120-mile inspection radius
- A 5.6-magnitude earthquake shook Oklahoma and up to six other states in the region on Sept. 3, 2016, near Pawnee, Okla. ODOT immediately responded after the 7:02 a.m. earthquake and sent inspection teams to look at bridges within a 30-mile radius of the earthquake's epicenter. No structural damage was found on the 180 state bridges inspected, however, cosmetic damage was found on SH-15 over Red Rock Creek in Noble County and on SH-108 over the Cimarron Turnpike in Payne County. On Sept. 7, the USGS revised the earthquake's magnitude to 5.8, making this the largest recorded earthquake in Oklahoma to date. ODOT widened its inspection radius to 60 miles from the epicenter, inspecting an additional 179 bridges. No damage was found.
How We Got Here
- In early 2014, ODOT met with California Department of Transportation officials, U.S. Geological Survey and the Oklahoma Geological Survey to learn from their experiences and create an interim policy for post-earthquake inspections. They helped advise ODOT on what to look for and how to make rapid assessments after an earthquake.
- In April 2015, ODOT hired consultant Infrastructure Engineers to help formulate an earthquake policy that is specific to Oklahoma. While ODOT does not believe any of its bridges are in any eminent danger from earthquakes, the agency wants to be prepared.
- The contract approved by the Oklahoma Transportation Commission tasked the consultant to draft an inspection protocol, create a field inspection manual, provide training, write a draft of an earthquake response plan and evaluate three types of highway bridges for seismic vulnerability, among other tasks.
- In 2011, a 5.6 magnitude earthquake near Prague in Lincoln County caused minor damage to the roadway on US-62. This damage was quickly repaired by ODOT maintenance crews at a cost of about $1,000. This has been the only reported earthquake damage to highways to date.
Last Modified on 10/17/2016
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