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Earthquakes have killed dozens of people, destroyed hundreds of homes and caused millions of dollars in damage in Hawaii.
Yet it’s hardly a top-of-mind issue for many in the islands, even with regular reminders like the magnitude 6.0 quake Sunday in Northern California.
The Napa earthquake wasn’t just a lot of spilled wine. More than 100 people were injured — three critically — and early estimates put total economic losses at more than $1 billion.
Based on historical data, experts say there is a high probability of a far more destructive earthquake rocking Hawaii — probably the Big Island — within the next decade.
“If you want to flip a coin and not prepare for the next 10 years, you’ve got a 50-50 chance of being right,” said Wes Thelen, a U.S. Geological Survey seismologist at the Hawaiian Volcano Observatory.
“It’s certainly coming,” he said. “There’s no doubt about it.”
Pinpointing when and where, though, is a lot harder. There’s no way (yet) to forecast an earthquake beyond best guesses based on statistical evidence.
Scientists can, however, say with a great deal of confidence that the Big Island is by far the most likely place in Hawaii for the next major earthquake to hit.
Thousands of quakes are recorded each year on or near the Big Island, which is more prone than the other main Hawaiian islands due to its larger land mass and active volcanoes.
Few earthquakes over the past century have been severe enough to level a home or collapse a bridge in Hawaii.
The most recent earthquake to be considered very destructive — scientists set that benchmark at magnitude 6.5 or higher — was in 2006 at Kiholo Bay.
There were no deaths from the 6.7 magnitude quake but power outages were reported statewide. There were landslides and more than $100 million in damage — some buildings were damaged 150 miles away on Oahu.
In 1975, a magnitude 7.7 quake in Kalapana on the Big Island generated a tsunami that killed two people who were camping. Some $4 million in damage was attributed to the disaster.
The most destructive earthquake in recorded history in Hawaii happened in 1868 on the south flank of Mauna Loa. With an estimated magnitude of 7.5 to 8.1, it wrecked areas all over the island and was felt all the way up the chain to Kauai. The quake set off a mudflow and tsunami that together killed 81 people and destroyed more than 100 homes.
Some experts suggest Hawaii has gotten lucky for a long time.
Thelen pointed to the fact that a large earthquake hasn’t struck the islands during business hours since 1973, when a magnitude 6.2 quake hit north of Hilo, causing $5.6 million worth of damage.
He questions how ready Hawaii residents are for an earthquake to hit in the middle of the day.
“What’s your response going to be when your kids aren’t sleeping in the bedroom next door?” Thelen said.
USGS is working with other government agencies, the University of Hawaii and the American Red Cross to improve earthquake preparedness through the 2014 Great Hawaii ShakeOut, part of a worldwide event Oct. 16.
The event involves teaching as many people as possible about earthquake readiness tips — like practicing drop, cover and hold-on drills — as well as survival strategies. More than 15,000 Hawaii residents took part in the event last year, and 15.1 million people participated worldwide.
“It’s not enough to just acknowledge that yes, we are prone to earthquakes,” Thelen said. “We want people to think about if there was an earthquake that happened right now, what would I do? What if I was at the supermarket? Or in my car? Or at the office?”
The Hawaii Emergency Management Agency (formerly Hawaii Civil Defense) is participating in the ShakeOut event and has been working to improve the state’s earthquake readiness.
Shelly Kunishige, the agency’s spokeswoman, said it conducts six to eight multi-hazard public outreach events per quarter, but its work is definitely not limited to informational meetings.
“What’s your response going to be when your kids aren’t sleeping in the bedroom next door?” — Wes Thelen, USGS seismologist
The agency has worked with other groups to provide disaster training for earthquake experts, emergency managers and local officials, as well as conducting mitigation outreach and awareness.
There have been some fiscal challenges, Kunishige said, such as the loss of a grant that was funding an informational website called Mother Nature. The agency is working to find a new portal to host that information.
Since the 2006 earthquake, the agency has worked with the Coast Guard, Navy, City and County of Honolulu and others to find a nautical alternative to Honolulu Harbor in case it is severely damaged in a natural disaster.
That harbor serves as the primary point of entry for most supplies and goods. Kalaeloa Barbers Point Harbor has been identified as an alternative, Kunishige said.
Hawaii has worked to improve its earthquake preparedness in other ways, too.
In 2012, the Big Island updated its building codes after the Legislature passed a bill in 2007 requiring statewide uniformity.
Hawaii County had been relying on building codes from the 1990s. That means buildings constructed in the past two decades didn’t take advantage of the latest and greatest ideas to mitigate damage.
Few homeowners or businesses voluntarily bring their old buildings up to the current code since there’s no legal requirement to do so and it can be costly. So more often than not it’s just the newly constructed buildings that will include the latest best practices, such as better ways to strengthen the building’s foundation or ways to keep walls from caving in.
It’s a serious problem that concerns one of the foremost Hawaii experts.
Gary Chock is a structural engineer and president of the Honolulu firm Martin & Chock, which government agencies have long enlisted for help on these matters. He’s authored key hazard studies, performed engineering risk analyses of major natural disasters and done damage mitigation projects and investigations.
He said the Big Island has a legacy of structures that weren’t built as well as they could have been because it was the most tardy county in the state in adopting new codes.
“Building codes do matter and affect the level of risk you have to earthquakes and hurricanes,” Chock said.
“Essentially, the lesson is that the state and counties should try to use the best available technology and you only get that if you adopt the most recent code. Otherwise, they’re basically ignoring the lessons learned from past disasters.”
Experts like Chock closely monitor the lessons that can be learned not just from earthquakes in Hawaii but on the mainland and elsewhere.
“Engineers basically don’t like people getting killed,” he said.
Often, there’s a knee-jerk reaction to disasters like the Napa earthquake. Photos of the damage included thousands of bottles of wine that rattled off their shelves and crashed onto storeroom floors.
Chock considered that quake a “firecracker” event. Explaining his comment, he pointed at a data visualization that demonstrates the exponential factor of the magnitude scale in which earthquake are measured.
Hawaii doesn’t have to worry as much about earthquakes like the Napa one causing similiar damage because most of the buildings here are not unreinforced brick buildings like in California. It’s mostly just the older buildings that are at risk.
Some of the most impressive damage from the 2006 quake in Hawaii happened to an old church and other buildings that were constructed of the same materials.
Honolulu Planning Director George Atta said the primary purpose of building, electrical and plumbing codes is the health and safety of the public.
The city uses the International Building Code as its model code and last adopted it in 2010, Atta said. The city is in the process of updating the latest version.
“Whenever there is a significant event, such as the Napa earthquake, international experts gather to study the damage and develop mitigation standards that are incorporated into each building code update.” — Honolulu Planning Director George Atta
“The City and County of Honolulu’s building code is established for the earthquake zone that we’re in, which is Zone 2, with 4 being the highest,” he said. “We review building permit applications to ensure that they meet these standards.
“Whenever there is a significant event, such as the Napa earthquake, international experts gather to study the damage and develop mitigation standards that are incorporated into each building code update. As part of the process of updating the county building codes, there is input at the state and county levels to address local conditions.”
Neil Erickson, plans and zoning manager for Hawaii County, said the new building codes are more prescriptive, recommending deeper footings, braced walls, additional nailing or more plywood depending on the case.
The state and counties don’t have too many disaster-proof places for people to go in case of an earthquake, Erickson said, making the building design of houses and businesses all the more important.
“I wouldn’t know where to run to if our house was falling apart,” he said, adding that it’s a “societal question” of whether government should provide such places.
USGS prepared this document to educate the public on what they need to know about earthquakes in Hawaii.