KAILUA-KONA — While Thursday’s magnitude-5.0 earthquake tremors were largely localized, they remind us of the islandwide effects of Hawaii’s earthquakes past.
The 10:30 a.m. quake, south of Pu’u ‘O’o, caused rockfalls and potentially another collapse in the crater on Kilauea Volcano’s East Rift Zone.
Some West Hawaii residents reported they felt the quake, according to the “Did You Feel it?” U.S. Geological Survey online earthquake report system.
Also prompted by magma movement was the earthquake of Nov. 29, 1975, the second-largest earthquake on the Hawaiian islands in recent history, only out-shaken by 1868’s magnitude-7.9 quake.
And actually, two temblors hit the morning of the ‘75 rumblings, the first a magnitude-5.7 and the second a magnitude-7.2, at 3:35 a.m. and 4:48 a.m., respectively.
The tremors roused West Hawaii residents and a small tsunami followed.
West Hawaii Today archives detail that the ‘75 tsunami had destructive impacts on Kona. Small boats off the coast were swamped, and debris washed up on Alii drive.
However, a tsunami is unlikely to occur again unless an earthquake is large enough, said Janet Babb, Hawaiian Volcano Observatory spokesperson.
“It’s really hard to say (if a large earthquake will occur),” Babb said. “Most of the large earthquakes on the island are tectonic.”
And even with a large earthquake, a specific set of conditions would be necessary to produce a tsunami, she added.
Another west-side impact from the ‘75 tremors was a few-hour stop to interisland flights.
For now, Big Island flight activity has remained unaffected by the volcano’s rumbles.
“The HDOT Airports Division will monitor the developments and continue conducting runway and terminal inspections,” Timothy Sakahara, state Department of Transportation spokesman, said in an email to West Hawaii Today.
“It is difficult to predict what the volcano will do; however right now there haven’t been any impacts on airport operations,” said Sakahara.
Tsunamis and tremors aside, eruptions from the volcano could impact West Hawaii’s air quality.
“There might be more vog than usual,” said Babb. “There might be some additional volcanic gases released and that might affect air quality.”
Vog contains chemicals that are damaging to plants, humans and other animals. Effects of vog include headaches, lethargy, watery eyes, sore throat, and difficulty breathing. Such symptoms are more common and pronounced in children and those with respiratory conditions.