Nav: Home

OU team details foreshock activities leading up to Pawnee earthquake

July 12, 2017

A University of Oklahoma geophysics professor, Xiaowei Chen, details the foreshock activities leading up to the Pawnee earthquake, and highlights the complicated relationship between seismicity and wastewater injection rates in a research study published this week in Scientific Reports. The study details the precursory earthquake (foreshock) sequences that culminated in the September 3, 2016, 5.8 magnitude earthquake near Pawnee, Oklahoma, which ruptured along the previously unmapped Sooner Lake Fault.

"In this study, we sought to better understand the nucleation processes of large earthquakes in Oklahoma, with the focus on the triggering process of the Pawnee earthquake. We began with an overview of occurrence patterns of earthquakes in Oklahoma, and their relationship with injection zones. Then, we focused on Pawnee County with a detailed analysis of the relationship between injection and precursory activities, as well as stress interactions between magnitude 3 plus foreshocks and the mainshock," Chen said.

Chen, a professor in the OU School of Geology and Geophysics, led the study and collaborated with Nori Nakata, OU geophysics professor; Colin Pennington and Jackson Haffener, OU graduate students; Jefferson Chang and Jacob Walter, Oklahoma Geological Survey researchers; as well as collaborators Zhongwen Zhan, Caltech; and Sidao Ni and Xiaohui He, China. The study suggests that the Pawnee earthquake was a result of a complicated interplay among wastewater injection, faults and prior earthquakes in the region.

Within the broader Pawnee area, increased seismic activities started in 2014, but only until May 2016 did researchers detect microearthquakes in the immediate vicinity of the Pawnee magnitude 5.8 epicenter. The foreshocks from May to September 2016 occurred in two major episodes, and the seismicity rate correlates with wastewater injection rates from nearby wells. The pattern of foreshocks also reveals possible aseismic (or slow) slip near where the magnitude 5.8 occurred, which appears to drive foreshocks to "migrate" along the Sooner Lake Fault. Additionally, the three largest foreshocks were optimally-oriented so that their slip may have promoted failure along the Sooner Lake Fault.
-end-
Part of this study was funded by the Oklahoma Governor's Emergency Fund to study induced seismicity, and the field deployment was supported by the National Science Foundation geophysics program with equipment supplied by the Incorporated Research Institutions of Seismology. The study was published online on July 10, 2017, by Scientific Reports at https://www.nature.com/articles/s41598-017-04992-z. For more information about this study, please contact Chen at xiaowei.chen@ou.edu.

University of Oklahoma

Related Earthquakes Articles:

Distant earthquakes can cause underwater landslides
New research finds large earthquakes can trigger underwater landslides thousands of miles away, weeks or months after the quake occurs.
New model could help predict major earthquakes
Nagoya University-led researchers characterized several earthquakes that struck South America's west coast over the last 100 years by using seismographic data, tsunami recordings, and models of the rapid plate movements associated with these natural disasters.
Forecasting large earthquakes along the Wasatch Front, Utah
There is a 43 percent probability that the Wasatch Front region in Utah will experience at least one magnitude 6.75 or greater earthquake, and a 57 percent probability of at least one magnitude 6.0 earthquake, in the next 50 years, say researchers speaking at the 2017 Seismological Society of America's (SSA) Annual Meeting.
Anticipating hazards from fracking-induced earthquakes in Canada and US
As hydraulic fracturing operations expand in Canada and in some parts of the United States, researchers at the 2017 Seismological Society of America's (SSA) Annual Meeting are taking a closer look at ways to minimize hazards from the earthquakes triggered by those operations.
Oklahoma is laboratory for research on human-induced earthquakes
Earthquakes such as the February 2016 magnitude 5.1 Fairview quake, November 2016's 5.0 Cushing quake, and the September 2016 5.8 Pawnee quake -- the state's largest in historic times -- have made Oklahoma a laboratory for studying human-induced seismicity, according to researchers gathering at the 2017 Seismological Society of America's (SSA) Annual meeting.
Prediction of large earthquakes probability improved
As part of the 'Research in Collaborative Mathematics' project run by the Obra Social 'la Caixa', researchers of the Mathematics Research Centre (CRM) and the UAB have developed a mathematical law to explain the size distribution of earthquakes, even in the cases of large-scale earthquakes such as those which occurred in Sumatra (2004) and in Japan (2011).
Manmade earthquakes in Oklahoma on the decline
Stanford scientists predict that over the next few years, the rate of induced earthquake in Oklahoma will decrease significantly, but the possibility for damaging earthquakes to occur will remain high.
Crowdsourced data can help researchers study earthquakes
A new study on how people feel the effects of earthquakes illustrates the value that members of the public can add to the scientific research process.
Humans have been causing earthquakes in Texas since the 1920s
Earthquakes triggered by human activity have been happening in Texas since at least 1925, and they have been widespread throughout the state ever since, according to a new historical review of the evidence published online May 18 in Seismological Research Letters.
Bubble volcano: Shaking, popping by earthquakes may cause eruptions
A new study on the connection between earthquakes and volcanoes took its inspiration from old engineering basics.

Related Earthquakes Reading:

Earthquakes (Let's-Read-and-Find-Out Science 2)
by Dr. Franklyn M. Branley (Author), Megan Lloyd (Illustrator)

The Great Quake: How the Biggest Earthquake in North America Changed Our Understanding of the Planet
by Henry Fountain (Author)

Earthquakes (Smithsonian-science)
by Seymour Simon (Author)

National Geographic Kids Everything Volcanoes and Earthquakes: Earthshaking photos, facts, and fun!
by Kathy Furgang (Author)

Earthquakes (True Books: Earth Science (Paperback))
by Ker Than (Author)

Earthquakes! (TIME FOR KIDS® Nonfiction Readers)
by Cy Armour (Author)

Quakeland: On the Road to America's Next Devastating Earthquake
by Kathryn Miles (Author)

Earthquakes: 2006 Centennial Update
by Bruce Bolt (Author)

Earthquakes: Geology and Weather (Science Readers)
by William Rice (Author)

I Survived the San Francisco Earthquake, 1906 (I Survived #5)
by Scholastic Inc.

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Approaching With Kindness
We often forget to say the words "thank you." But can those two words change how you — and those around you — look at the world? This hour, TED speakers on the power of gratitude and appreciation. Guests include author AJ Jacobs, author and former baseball player Mike Robbins, Dr. Laura Trice, Professor of Management Christine Porath, and former Danish politician Özlem Cekic.
Now Playing: Science for the People

#509 Anisogamy: The Beginning of Male and Female
This week we discuss how the sperm and egg came to be, and how a difference of reproductive interest has led to sexual conflict in bed bugs. We'll be speaking with Dr. Geoff Parker, an evolutionary biologist credited with developing a theory to explain the evolution of two sexes, about anisogamy, sexual reproduction through the fusion of two different gametes: the egg and the sperm. Then we'll speak with Dr. Roberto Pereira, research scientist in urban entomology at the University of Florida, about traumatic insemination in bed bugs.