Earthquake readiness in Caribou

Last week’s catastrophic earthquake in Myanmar was almost literally halfway across the world, but the reality of earthquakes along the Rocky Mountain and Wasatch mountains is all too close to home.  According to USGS mapping data, Caribou County joins most of Southeast Idaho in being labeled a high risk earthquake area.  It’s only the extremely long scale of geologic time that hides the frequency of earthquake events in and around the area.  For many years now, residents of this part of the state have been worried about the “Yellowstone Caldera” and the potential for a “supervolcano event.”  The phrasing is certainly alarming, but a standard earthquake event is probably more likely (and certainly plenty destructive enough) in most of our lifetimes.

Next week, Caribou County should be essentially finalizing its “All-Hazard Mitigation Plan,” which is a grant prerequisite from FEMA for disaster mitigation funds, according to Caribou County Emergency Services Manager Eric Hobson.   “By the end of the week, Bancroft, Grace, Soda Springs, and the Commissioners will hopefully have signed off on it so it can be officially approved.  FEMA might take a bit longer.  I don’t foresee any changes between now and then, though.”

“When we had the last one, that spurred some action.  Obviously, we know we’re earthquake prone.  There are some places that will tell you they can predict a quake exactly, but most of the experts we talked to seem to agree that it’s really an educated guess.”  Hobson and the county have been working with some of those experts at getting better readings on the geology of the area.   

The most recent larger earthquake was a 4.2 magnitude quake in January of 2021 near the Caribou/Bear Lake border.

“It was out by Fossil Basin, about six miles east of Soda Springs.  That was over 4, so it was pretty significant,” Hobson said.  “I don’t mean to sound nonchalant about the smaller ones, but we get a lot of smaller ones—a three or a two—a few times a year.  They come, they shake a little bit, we talk about it on Facebook and life moves on.”

“But we did earthquake surveys in the aftermath of the 2021 quake,” Hobson said.  The surveys were performed as part of an HMGP (Hazard Mitigation Grant Program) with the state of Idaho.  “They came and surveyed a lot of our public infrastructure and found that we have a lot of ‘concern’ buildings, but not any more than other communities with aging buildings.  Idaho implemented building construction for earthquake years ago.  But our historical buildings are a little different.  We looked at options for grants and retrofitting.  Unfortunately, retrofitting a building often means paying what you would to build a new building three times the size.”

There are some locations with the resources to fully retrofit old buildings to quakeproof them—Japan is one of the clearest examples of undertaking such a feat—but for most cities, counties, and even countries the costs of doing so are prohibitive.

“So, we haven’t pursued some of those options,” Hobson said.  “We have pursued education, though.  We’ve had people come up to speak about earthquake readiness, and we’ve identified some of our what we can do moving forward in the mitigation plan.  We monitor it, we look at it, we promote earthquake safety, but unfortunately we do have a number of hundred plus year old buildings where we don’t always have a lot of options.”

Earthquakes are listed alongside wildfires and winter storms as the biggest potential disaster threats the county faces.  The mitigation plan was developed over the course of a number of public and stakeholder meetings involving residents, emergency service personnel, city and county officials, and many others.  Threats such as power outages, internet attacks, domestic terrorism, flooding, civil unrest, and a range of other potential issue were discussed and various mitigation plans were developed for those threats considered most urgent.

Having the threats identified in the plan, and a record of the county’s mitigation solutions for them,  provides a means for securing disaster funding through FEMA in the event of an emergency.  The sheer scale of most natural disasters in terms of financial recovery is staggering, which is one strong reason to make sure that all available political, economic, and human resources are ready for deployment.

It also explains why the mitigation part of the plan is so essential.  As Hobson explains, “the saying is that one dollar on mitigation makes up for four dollars spent on disaster.”

While it’s obviously a good thing that there has not been a recent major earthquake, it also means that there is not a lot of direct experience with them.

“That quake [in 2021]  was a learning experience for me.  I’m in my garage, and I look up and my roof is shaking as I’m sitting there.  I can watch the joists going back and forth and I’m thinking ‘well, that’s not good.’  And then after a minute I realized I’d better go outside because, you know, my garage was shaking.  And then I realized that, holy crap, we just had an earthquake!  I remember it was a Sunday afternoon, so I had to figure out who do you call for this?  How do you take care of this?  Finally, I called the weather service because I knew there was someone there.  And they just said, ‘oh yeah, we felt it too in Pocatello.’  They told me to call the USGS, but of course no one was there because it was Sunday.  Ultimately, they told me that they contract out for earthquake monitoring and told me to call University of Idaho.  I called them, and they told me that since we were in the Bear River Basin, it was the U of U that I needed to talk to.”

“They were great to work with.  They were up here for a week with their team.  They came up here with their surveys, installed the seismographs and got us connected.”

With monitoring providing some potential early warning, the county will move forward with other mitigations outlined in the All-Hazard plan, we should be available to the public after it is approved.  The plan covers many potential natural disasters and threats, with Hobson agreeing that wildfire is perhaps the most pressing.

“Every five years, FEMA requires us to have a plan in place.  We make the plans, we identify the hazards, and we identify plans.  A lot of the projects I do have to do with wildfire mitigation.  We’re doing fuel mitigation right now.  We’ve put in some road projects that we’re hoping to get funded through the process.  And the cities are involved with the plans.  A lot of city projects involving infrastructure upgrades and other things are in there.”

The county has been using SICOG (Southeast Idaho Council of Governments) to administer grants and contracting for disaster mitigation projects and Hobson feels that “they’ve been great.  They are unbelievably fairly priced—they look at the budget and make sure they can work it to support communities like ours in the best way possible.  It’s been super nice for us.”

It can be hoped that no serious earthquake event will occur in the area anytime soon, but it’s somewhat reassuring to know that if it does those who will be on the front lines of response are taking it seriously.