Volcano Watch: Remembering a time when I forgot Hawaiʻi has earthquakes
“Volcano Watch” is a weekly article and activity update written by U.S. Geological Survey Hawaiian Volcano Observatory scientists and affiliates. Today’s article is by Hawaiian Volcano Observatory Seismic Network Manager Jefferson Chang.
I am a seismologist at Hawaiian Volcano Observatory — earthquakes are always on my mind. But this wasn’t always the case.
By any number of measures, Hawaiʻi Nei is paradise. Growing up in Waimānalo on Oʻahu, with picturesque sandy beaches stretching from Bellows to Makapuʻu, natural disasters were few and far between.
Hurricane ʻIniki is the one that sticks out most when looking back at my childhood. Other than hurricanes, I don’t remember much else disrupting life as I knew it, including earthquakes.
I knew I wanted to pursue a degree of some sort, so I went to Leeward Community College for a few years. Eventually, I moved to the continent and ended up studying geology.
I know what you’re thinking, “rocks are so amazing!” and I completely agree. But more so than looking at rocks, I enjoyed trying to figure out how rocks came to be, how they got to where they are or how they moved to create mountains that span continents.
In Hawaiʻi, we have basalt rocks; maybe a few more if you really get nerdy about it, but it’s mostly basalt. Around the world, there are many more kinds of rocks. I wanted to see all of them.
I was looking at so many rocks that years came and went, and by the time I realized it, I was doing a doctoral degree in geophysics — more specifically, studying the processes of faulting (rocks breaking) and seismology (how the ground shakes).
By this time in my life, I had written off living back home if I was to pursue a career in geoscience.
It wasn’t until I was waiting for a flight out of the San Francisco airport that I met a random person who asked if I was from Hawaiʻi — which was pretty obvious because I almost always walk around in slippahs — that triggered a tectonic shift in my way of thinking about returning home.
We got to talking, and this random person turned out to be Paul Okubo, former seismic network manager and research seismologist at Hawaiian Volcano Observatory, now retired.
As soon as he mentioned he was from the observatory, memories of my eighth-grade field trip to the Big Island came flooding back. In a seismic snap, I remembered Hawaiʻi has earthquakes.
Because I grew up on Oʻahu, far from the typical epicenters of the Island of Hawaiʻi, earthquakes were rarely felt. I surely don’t remember feeling any from hanabada days. That chance meeting I had at San Francisco provided a beacon for me to find my way back home, while still doing what I love doing.
The fact that the Island of Hawaiʻi has active volcanoes means we have lots and lots of earthquakes.
Most of these earthquakes aren’t strong enough to be felt let alone devastating. But every once in a while, large earthquakes are produced, like the one earlier this year.
The magnitude-6 earthquake that nucleated under the west side of the Island of Hawaiʻi on May 22 was felt throughout the entire state. It is the most-reported earthquake to date — “Did You Feel It” reports came in from every populated island.
Rockslides blocked roadways. Houses were damaged. Hundreds of homes lost electricity. A federal disaster was declared.
The magnitude-6 earthquake is a harsh reminder that we cannot forget about earthquakes.
We should always be thinking about earthquake preparedness. Yes, we should drop, cover and hold on as soon as earthquake shaking begins — this is a reactive drill.
But beyond reacting to ground shaking, we can also take proactive steps in earthquake preparedness.
The Great Hawaiʻi ShakeOut web page has resources that show how anyone can be better prepared for the next big earthquake.
While on the ShakeOut web page, you, your ʻohana, community or organization can sign up to participate in the Great Hawaiʻi ShakeOut drill, which is an annual minute-long earthquake drill on the third Thursday of October, with the “earthquake” time depending on the date.
Join Hawaiian Volcano Observatory at 10:15 a.m. next week Thursday, Oct. 15, from wherever you might be throughout the Hawaiian Islands as we practice what to do when the ground starts shaking: DROP, COVER, HOLD ON.
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VOLCANO ACTIVITY UPDATES
KĪLAUEA volcano
VOLCANO ALERT LEVEL: Watch
Kīlauea has erupted episodically since Dec. 23, 2024, within the summit caldera.
North and south vents in Halemaʻumaʻu Crater continue to intermittently erupt spatter, with strong glow and flames visible overnight. Sulfur dioxide emissions are in the range of 1,000 to 5,000 tonnes per day.
Kīlauea’s summit region remains at a high level of pressurization. Current conditions remain favorable for another fountaining episode or change in eruptive activity. No unusual activity has been noted along Kīlauea’s East Rift Zone or Southwest Rift Zone.
MAUNA LOA volcano
VOLCANO ALERT LEVEL: Normal
Mauna Loa is not erupting. Read the most recent monthly Mauna Loa activity update online.
Hawaiian Volcano Observatory continues to closely monitor Kīlauea and Mauna Loa.
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EARTHQUAKE ACTIVITY UPDATES
Three earthquakes were reported felt during the past week in the Hawaiian Islands:
- MAGNITUDE-3 earthquake at 6:39 p.m. Oct. 6 located 6 miles south-southeast of Leilani Estates at a depth of 5 miles.
- MAGNITUDE-3.6 earthquake at 2:31 a.m. Oct. 5 located 7 miles southwest of Volcano at a depth of 17 miles.
- MAGNITUDE-3.5 earthquake at 7:55 a.m. Oct. 2 located 3 miles west-southwest of Volcano at depth of 0 miles.
Visit the Hawaiian Volcano Observatory website for past “Volcano Watch” articles, Kīlauea and Mauna Loa updates, volcano photos, maps, recent earthquake information and more. Email questions to askHVO@usgs.gov.
