Kailua-Kona is not in immediate danger from volcanic activity, but it’s not volcano-free either. The town sits on the western flank of Hualālai, a volcano the USGS classifies as having “high” threat potential, and it falls within reach of lava flows from both Hualālai and Mauna Loa. For most visitors and residents, the day-to-day risk is low. The more regular concern is vog, the volcanic smog that drifts over from Kīlauea and periodically degrades air quality along the Kona coast.
Two Volcanoes That Could Affect Kona
Kailua-Kona sits directly on the slopes of Hualālai, which last erupted in 1800 and 1801. During that eruption, two large lava flows reached the ocean. The Kona International Airport is literally built on top of one of them. Hualālai has not erupted since, but the USGS considers it a potentially dangerous volcano that is likely to erupt again. It ranks third among Hawaiian volcanoes for long-term lava flow threat, behind Kīlauea and Mauna Loa.
Mauna Loa, the massive shield volcano to the east, poses a second risk. Its Southwest Rift Zone can send lava flows toward the Kona and Kaʻū districts on the western coast. Mauna Loa last erupted in 2022 (from its Northeast Rift Zone, away from Kona) and before that in 1984. USGS scientists use eruption data going back to 1843, combined with topographic modeling, to forecast which communities could be in the path of future flows. The Southwest Rift Zone is not currently active, but it has produced flows aimed at the Kona side in the past.
What Lava Flow Hazard Zones Mean
The USGS divides the Big Island into nine lava flow hazard zones, with Zone 1 being the most dangerous and Zone 9 the least. These rankings are based on where historic and prehistoric eruptions have occurred and how frequently lava has covered each area. Kailua-Kona falls in Zone 4, which reflects moderate long-term risk. For comparison, active rift zones on Kīlauea and Mauna Loa sit in Zones 1 and 2, while the northern tip of the island near Kohala is Zone 9.
Zone 4 means lava flows have reached the area in the past but infrequently. It’s not the kind of zone where you’d expect to deal with an eruption in any given decade, but over centuries, flows have covered that ground. The practical takeaway: Kailua-Kona is significantly safer than communities like Leilani Estates (Zone 1, partially destroyed in 2018), but it is not outside the reach of volcanic hazards entirely.
Vog Is the More Common Problem
If you’re living in or visiting Kailua-Kona, volcanic smog is the hazard you’re most likely to actually experience. Vog forms when sulfur dioxide and other gases from Kīlauea’s eruptions react with sunlight and moisture in the air. Prevailing trade winds push this haze around the southern tip of the island and up the Kona coast, where it can settle in and linger.
During Kīlauea’s eruption that began in December 2024, air monitoring stations across Hawaiʻi Island recorded periodic spikes in sulfur dioxide and fine particulate matter. Most readings on the Kona coast showed good or moderate air quality, but stations in southern parts of the island occasionally hit unhealthy levels. Conditions can shift quickly based on wind direction and how much gas the volcano is emitting.
For most healthy adults, vog causes temporary irritation: stinging eyes, scratchy throat, mild coughing. People with asthma, bronchitis, emphysema, or heart disease can experience more serious symptoms, including difficulty breathing or flare-ups of existing conditions. Children, elderly individuals, and pregnant women are also more vulnerable. On heavy vog days, the Hawaii Department of Health recommends staying indoors, closing windows, and setting air conditioners to recirculate. If you have a respiratory condition and plan to spend time in Kona, keeping your medications accessible is a practical precaution.
Earthquakes on the Kona Coast
Volcanic activity drives most of the seismic activity on the Big Island. On average, the island experiences one earthquake above magnitude 5.0 every year and a half, and one above magnitude 6.0 roughly every six years. Large, damaging earthquakes struck beneath the Kona coast in 1950, 1951, and 1952, though that area has been relatively quiet since. The 2006 Kīholo Bay earthquake (magnitude 6.7) was centered off the northwest coast and caused significant damage in parts of West Hawaiʻi, including broken water mains and structural damage to older buildings.
Earthquake risk in Kona is real but comparable to living in other seismically active regions. Buildings constructed to modern codes handle moderate shaking well. If you’re buying property, the age and construction of the building matters more than being in Kona specifically.
Tsunamis and Volcanic Landslides
Mapping of the ocean floor around Hawaiʻi has revealed ancient debris fields from massive flank collapses, where huge chunks of volcanic rock slid into the sea and likely generated enormous tsunamis. One such collapse left visible cliff scars along the coast, with debris scattered up to 100 kilometers (62 miles) offshore. These events sound terrifying, but they occur on average once every 350,000 years across the Hawaiian Island chain. Scientists do not consider this a realistic near-term threat.
Tsunamis generated by distant earthquakes (in Alaska, Chile, or Japan) are a more practical concern for any Hawaiian coastline, including Kona. Hawaiʻi has a robust warning system for these events, and coastal evacuation zones are clearly marked throughout Kailua-Kona.
What Happens if an Eruption Threatens Kona
Lava flows on Hawaiʻi move relatively slowly compared to other volcanic hazards like pyroclastic flows. In most Hawaiian eruptions, people have hours to days of warning before flows reach populated areas. The Hawaiian Volcano Observatory monitors Hualālai and Mauna Loa continuously with seismometers, GPS stations, and gas sensors. A significant uptick in earthquakes beneath Hualālai or inflation of the volcano’s surface would trigger alerts well before any lava appeared.
If an eruption were to threaten Kailua-Kona, Hawaiʻi County Civil Defense would issue evacuation orders based on HVO scientists’ tracking of flow location and direction. One important factor to keep in mind: lava flows can cut off roads. Kailua-Kona’s main highway corridors run along the coast, and a flow crossing one of those routes could complicate evacuation. Knowing your evacuation routes in advance, and not waiting until the last minute to leave, is the standard advice for anyone living downhill of a rift zone.
For the typical visitor spending a week in Kona, the chance of a volcanic event disrupting your trip is extremely small. For residents, the risk profile is more like living in earthquake country: not something that affects daily life, but worth understanding and preparing for over the long term.