Kokua Line: What caused East Oahu homes to shudder?

Question: What caused homes in East Oahu to shudder Thursday afternoon? It’s all over social media but I don’t see the cause. It seemed like an earthquake but it wasn’t. What does the military say?

Answer: The military branches we’ve heard back from say they did not cause the disturbance. Since Friday, Kokua Line has called and emailed multiple branches and bases, asking whether military activity by land, air or sea could explain what numerous residents initially assumed was an earthquake or aftershock at about 2:25 p.m. Thursday, felt most strongly in East Oahu; we heard from readers or saw social media reports from Diamond Head to Kalama Valley. In addition, more than 450 people reported the shaking to a commercial website that tracks seismic activity worldwide.

Some residents said they heard a very low rumble and felt two waves of motion ripple through their homes about a second or a fraction of a second apart. Some said their windows rattled or their roofs heaved. It was over in a few seconds.

However, the U.S. Geological Survey’s official seismic network did not record an earthquake around that date and time, and the National Weather Service said nothing on its radar could explain the incident. “This did not appear to be weather-related,” meteorologist Thomas Vaughan said by phone Friday. Residents had called the NWS immediately after the event, asking about lightning, thunder or high winds — it was none of those things, he said.

With an earthquake or storm ruled out, we turned to the military for an explanation, but by deadline Tuesday had found none. Some residents had speculated that military jets may have caused unusual sonic booms because of the Kona low weather pattern that lingered last week, with extensive cloud cover. The U.S. Air Force has a fact sheet about sonic booms at 808ne.ws/sboom.

“There were Hawaii Air National Guard F-22 Raptors flying at that time, however they did not cause the noise that was heard,” retired Maj. Jeff Hickman, spokesperson for the state Department of Defense, said Tuesday in an email.

Hickman said he asked a seasoned pilot whether the weather may have caused an unusual effect and was told no, it wasn’t a factor. “The location that our F-22s were training at was too far out to sea for Oahu to hear their sonic booms, if they performed any,” he said.

We also heard back from officials with Marine Corps Base Hawaii, U.S. Army Garrison Hawaii and Joint Base Pearl Harbor-Hickam, who said there was no Marine, Army, Air Force or Navy training scheduled that day that could explain the disturbance.

As of deadline Tuesday, Kokua Line was waiting to hear back from the U.S. Indo-­Pacific Command and Pacific Air Forces, which includes the Space Force.

Although we haven’t received any reports of damage from Thursday’s event, people do want to know what happened, so we’ll continue to follow up.

Q: Auwe! My dermatologist advises me to wear sunscreen daily, so I bring a lot when I travel. I’ve never had trouble before, but flying home they enforced the “3-1-1 rule” and I had to throw out a tube.

A: The Transportation Security Administration’s 3-1-1 rules says that passengers may bring a quart-size bag filled with containers of liquids, aerosols, gels, creams and pastes through the airport security checkpoint as long as each container holds 3.4 ounces or less. “Medically necessary” liquids, gels and aerosols over 3.4 ounces are allowed in “reasonable quantities,” but over-the-counter sunscreen is not considered to be medically necessary as a carry-on item, it says. Larger containers of sunscreen are allowed in checked bags.

Write to Kokua Line at Honolulu Star-Advertiser, 500 Ala Moana Blvd., Suite 7-500, Honolulu, HI 96813; call 808-529-4773; or email kokualine@staradvertiser.com.