University of Iowa using new equipment to learn from earthquakes

IOWA CITY - Before noon Friday, in Trowbridge Hall on the University of Iowa campus, scientists and students alike watched in real time as seismic waves rocked the island nation of Japan 6,000 miles away.

'The waves started to roll in here about 10 minutes after the earthquake started in Japan,” said Bill Barnhart, an assistant professor with the UI Department of Earth and Environmental Sciences. 'It takes about 10 minutes to get from Japan to Iowa City.”

Barnhart, who took the UI job last year after previously working at the U.S. Geological Survey's National Earthquake Information Center in Colorado, administers the university's new seismometer installed on campus in the basement of Trowbridge Hall in November.

The weekend's massive earthquakes in both Japan and Ecuador are the first major tremors the UI equipment has recorded, and Barnhart said it worked wonderfully to capture the strength of the quakes and the types of seismic waves - among other things.

'We have absolutely beautiful recordings for those earthquakes,” he said.

The data, which is continuing to roll in, will be used both for outreach and in the classroom to study the earth's interior structure and how quakes occur by analyzing the different types of seismic waves and their varying effects.

'It's about better characterizing earthquakes and better locating them,” Barnhart said. 'That helps us to respond to them better.”

Because earthquakes start with deep seismic waves that occur before the surface ground starts shaking, some at-risk nations and communities have or are implementing early-warning systems giving them 10 to 15 seconds to move under a pillar, run outside, or even shut down a nuclear reactor.

Barnhart stressed that Iowa is not in the business of predicting earthquakes - its seismometer can report deeper waves minutes after they occur, but it takes even longer for surface shaking to transmit to Iowa.

'The waves that people would feel take more than an hour and a half to arrive,” he said.

Rather, Iowa's seismometer readings are ideal for unpacking earthquake source properties. The UI equipment, which includes a hallway monitor outside Barnhart's office, can track waves that bounce off the earth's inner core and travel to the surface.

'When students walk by, we can talk about earthquakes and point out the interesting features,” he said.

Although Barnhart said he watched in real time Friday's 7.0 quake near Kumamoto, Japan, the 7.8 earthquake that subsequently hit Ecuador occurred Saturday evening in Iowa, meaning he was not in the office.

But both quakes, he said, will be interesting to analyze - as they appear to be unrelated and quite different.

As for the Japan quake, Barnhart said, it was relatively shallow, not quite as strong as the one in Ecuador, and preceded by two slightly smaller quakes - one registering 6.2 in magnitude at 9:26 p.m. Thursday, Japan time, and one registered 6.0 in magnitude at 12:03 a.m. Friday.

'The Japan quake was preceded by foreshocks - earthquakes that happen a couple of days, one to two days, before,” Barnhart said. 'That is not too uncommon, but it's not terribly common either, and it might indicate that one of the smaller earthquakes triggered the larger.”

That could be important in understanding the potential impact of future earthquakes.

'People are still digging up and wrapping up what happened,” Barnhart said. 'But there will be lots and lots of research.”

Due to the nature of the Japanese quake - and the quality of that country's infrastructure - Barnhart said much of that follow-up investigation will occur on the ground.

'With the Japan earthquake, lots will be done with ground instruments and going out into the field and looking at surface ruptures,” he said. 'But Ecuador is different.”

Because the quake that shook that South American nation was much deeper and didn't result in 'surface rupture,” the main mode for follow-up research will be satellite imagery.

'They will look at the different types of waves that come in and how to use the time that those arrive to locate the earthquake,” Barbhart said.

That quake also could take longer to assess, as the nation is not as advanced, had weaker infrastructure, and suffered more damage.

'It's going to be an interesting earthquake,” he said. 'But Ecuador doesn't have the level of scientific instruments on the ground, so it will take longer.”

Even though the two earthquakes occurred at similar times and both were strong, Barnhart said they're not related and they're not indicative of any uptick in earthquake frequency. In fact, he said, earthquakes occur all the time, 'and it's just occasionally that they happen where people feel them.”

'Earthquakes of these magnitudes are happening at about the rate you expect,” he said.

The type of earthquake, the strength, and the preparations in place also factored into the level of destruction and need for relief in Japan and Ecuador.

The Japan quakes have killed more than 40 people and injured more than 1,000, according to media reports. The Ecuador quake, which hit hardest near the coastal Manabi Province, has killed more than 400 people and injured 2,500-plus - and rescue crews are continuing to comb through the rubble.

'Japan has excellent building codes for earthquakes,” Barnhart said. 'But other countries don't implement as rigorous building requirements - so shaking can lead to significant loss of buildings and life.”