Tsunamis generated by earthquakes on the Alaska Subduction Zone are a persistent risk in the Pacific Northwest. Decisions being made in the other Washington regarding the fate of nine unassuming and relatively inexpensive pieces of technology in Alaska will make our region less nimble in reacting to distant-source tsunamis.

Last month, nine seismic monitoring stations in Alaska were shuttered after the federal government declined to renew a $300,000 grant from the National Oceanographic and Atmospheric Administration to continue keeping them online. Local and regional emergency management officials have said that while it shouldn’t drastically impact the emergency response in the event of a tsunami generated off the seismically active Alaskan coast, it will decrease their response time.

The stations collected data that helped researchers determine the magnitude and shape of earthquakes along the Alaska Subduction Zone. The fault regularly produces powerful earthquakes and is the nearest threat that the U.S. West Coast faces when it comes to distant tsunamis; waves generated by a quake along the Alaska Subduction Zone would reach the shores of the Pacific Ocean in 3-4 hours.

“It’s not the end of the world” that the stations have gone offline, according to Pacific County Emergency Management Agency Director Scott McDougall, but he noted it will have an effect on the timeliness of the agency’s response in the event that an earthquake along that fault causes a tsunami.

“We’re concerned about this,” McDougall said. “We have a fairly large toolbox, but we’re losing an important tool out of that toolbox. The analogy I might use would be if this is a torque wrench, we still have a crescent wrench and sockets in the box that we can use in place of the tool that we’re losing.” Other tools

With the National Tsunami Warning Center no longer being able to receive information from the Alaska Earthquake Center, McDougall said earthquakes in the affected area will still be picked up by seismometer sensors all over the region — as far south as Portland.

“Those readings will be available, they just may be more delayed,” McDougall said, roughly estimating it could take an additional 15 minutes compared to when the Alaskan seismic stations were still online.

The NTWC will still have the ability to read DART buoys, which are positioned all along the Pacific Ring of Fire and report sea level measurements to warning centers that allow them to produce more accurate tsunami forecasts.

“They’re still gonna have their basic capability, it’s just going to slow down notifications regarding a distant-source tsunami in the state of Alaska,” McDougall said. “We are adapting and we are making plans to adapt to our new reality. We’re not happy about it, but I don’t know that the public will see a huge difference.”

Distant vs. local tsunamis

In addition to distant tsunamis taking a much longer time to reach the shores of the peninsula than a tsunami generated by an earthquake along the Cascadia Subduction Zone, when the first wave could arrive in as soon as 15-20 minutes, the threat posed to peninsula life and property by distant tsunamis are also expected to be more muted in scale compared to a local-source tsunami.

The most significant distant tsunami to affect the peninsula in recent history was generated by the 1964 Good Friday earthquake that struck near Anchorage, Alaska. The quake, with a magnitude of 9.2, unleashed a 12-foot wave in Seaview that had dissipated by the time it reached Pacific Avenue. No lives were lost, but tents and cars of weekend campers were washed away on the beach.

“We have modeling coming out that’s showing we can issue much more targeted tsunami warning information [in the event of a distant tsunami] and that most people on the Long Beach Peninsula are not going to have to evacuate,” said McDougall, adding that new local plans based on that modeling cannot be released until the peer-review process has been completed.

In the case of a threatening distant tsunami, All Hazard Alert Broadcast (AHAB) sirens will be activated, reverse 911 calls and text messages will be sent out, and PCEMA will post information on its website (pcema.info) and Facebook page (facebook.com/PCEMA) among other efforts to try and inform the public.

Local-source tsunamis are the most severe and widespread threat facing the peninsula, and people will not need to wait for guidance from authorities to know that they need to evacuate — if you live in a tsunami inundation zone and feel the ground shake for at least 45 seconds, seek higher ground or move inland immediately. Tsunami evacuation maps for all of coastal Pacific County can be found at pcema.info/plans.

McDougall said he’s not currently concerned about losing federal funding for seismic stations that monitor the Cascadia Subduction Zone. But thanks to Mother Nature’s own earth-moving warning system, people will know immediately if they need to take action in the event of a local tsunami — unlike a distant tsunami, where they rely on human initiative both near and far.

“There was a time when that information would come down and I had a moment to take a deep breath,” McDougall said regarding the expected delay caused by the Alaskan seismic stations going offline. “I probably am going to lose that time to take a deep breath and I’m just going to have to get the information pushed out faster on our end.”