Scientists say Thursday’s earthquake in Russia is aftershock from July, expect it to continue

HONOLULU (KHON2) — There was no tsunami threat to Hawaii after a strong earthquake struck off Russia Thursday morning. It’s the same region that triggered a tsunami warning for us back in July.

Scientists say Thursday’s quake is connected to that earlier activity, warning we could see more of it in the weeks ahead.

Everyone remembers the gridlock on Oahu in July because of a tsunami warning. That was triggered after an earthquake at the Kamchatka Peninsula in Russia. Scientists say Thursday’s earthquake is an aftershock from that one.

“So the aftershock sequence from a big earthquake like the 8.8 can happen for weeks, months, even years after,” said Dr. Helen Janiszewski, UH Manoa Department of Earth Sciences Assistant Professor.

After an earthquake, scientists monitor hundreds of sensors spread out across the Pacific to check if a tsunami was generated.

‘They’re amazing because they’re sitting down 4000 meters below the seafloor, below the sea surface and they’re able to measure millimeter changes in water height,” said Dr. Steven Colbert, UH Hilo Marine Science Associate Professor.

Because tsunami waves can be spread out 15 minutes apart, this creates some lag time for the Pacific Tsunami Warning Center to issue its alerts.

There are many factors involved if a tsunami is generated after an earthquake. Some of them include the shape of the ocean floor, how deep the earthquake occurred, and, of course, the size. But when it comes to magnitude, scientists say, don’t let that number fool you.

“We can have cases, and we know we have had cases, where we’ve had lower magnitude earthquakes that, for whatever reason, generate a particular type of fault slip or other secondary effects that amplify the tsunami,” said Janiszewski. “So it is very important, just because you see a lower magnitude earthquake is not a sure sign that the tsunami generated is going to be lower.”

Scientists say we were extremely fortunate in July. And because earthquakes can happen throughout the Pacific, where we might not have as much lead time, it’s crucial for the public to heed warnings.

“There’s a lot of great information that’s coming out, and they’re there,” said Colbert. “They respond so quickly to when these happen in order to keep our community safe. It’s really important to pay attention to what they’re doing.”