Seismologists Say They're Forecasting Earthquakes
OKLAHOMA CITY - They're a constant part of our weekly and sometimes daily reports. The Oklahoma Geological Survey says we've already had more 3.0 magnitude or greater earthquakes this year than all of 2013! In the same way we forecast the weather, can we forecast earthquakes?
Dr. Thomas Jordan with the Southern California Earthquake Center located at the University of Southern California is trying to figure that out.
"We look at each fault and ask, how active is it? How big an earthquake can it produce? How frequently will it produce earthquakes?" said. Dr. Thomas Jordan. "From that data, we put together a statewide earthquake forecast."
Dr. Jordan showed me a simulation of how earthquake forecasting works.
Sophisticated models like that allow scientists at USC to predict just how much the Los Angeles area would shake during a major earthquake. But we don't have models like that for Oklahoma.
Director of the Oklahoma Geological Survey and OU Geophysics professor Dr. Randy Keller isn't fully convinced in earthquake forecasting.
"Tomorrow we probably won't have any earthquakes, but look out for next week. That kind of forecasting is not with us at this point," said. Dr. Randy Keller.
"Our forecasting models are not bad at predicting where and how big the earthquakes might be," Dr. Jordan said. "Even know something about how frequently they occur. We can't say when they're going to occur."
Determining the location and size of a future earthquake starts with studying the sequences.
Dr. Jordan said, "My guess is when we start getting earthquake sequences, bigger than what you're seeing in Oklahoma, that we'll begin to understand how those sequences evolve."
Dr. Jordan said forecasting Oklahoma earthquakes is a completely different challenge because he believes they're man made.
"It's pretty clear they're related to deep injection of waste water and other fluids deep into the earth's crust," said. Dr. Jordan.
Jordan added there's only one way to forecast those.
"In a place like Oklahoma, you're going to be able to have earthquake forecasts based on deep injection activity," said Dr. Jordan.
"The activities are not causing a situation where there's earthquakes occurring where they would not occur sooner or later anyhow," Dr. Keller said.
"We can't say, hey, next week there's a 70% chance of having a big earthquake on the San Andreas fault," Dr. Jordan said. "We do know the probability of having earthquakes change with time."
While earthquake forecasting is not like predicting a thunderstorm, one area that scares Dr. Keller is the Meers fault north of Lawton.
"In areas that don't have well known faults that have a history of movement, you know they're sitting there and waiting to cut loose at some point," Dr. Keller said.
Dr. Jordan has his eyes on a different part of the country, the area of the San Andreas fault that's south of Los Angeles.
"That part of the faults are ten months pregnant and we are concerned that the entire southern San Andreas fault is locked, loaded and ready to roll," Dr. Jordan said.
While Dr. Jordan says Oklahoma earthquakes are harder to predict, they do have a scientific benefit.
"Sequence of earthquakes occurring in Oklahoma is going to provide very rich data source," Dr. Jordan said. "Understand how rocks in that part of the world interact with each other to cause earthquakes."
Dr Keller says small earthquakes can also be good for Oklahoma because they release stress in the earth's crust. And an explanation for the frequency of earthquakes in Oklahoma may have to do with improved technology.
Dr. Keller said, "There were zero seismograph stations prior to late 1970s. There were roughly ten until about 2006. Now we have 20 first class stations."
The first earthquake was reported in 1882. Since then, there have been at least one earthquake in every county in Oklahoma, except two: Jackson and Washington counties.
Earthquake Size Explanation:
Magnitude 4 or less: small
Magnitude 4-6: intermediate
Magnitude 6 or greater: large