In 2025, professor Bruce Houghton retired from the University of Hawaii at Manoa after 25 years as the Gordon A. Macdonald chair of volcanology. He was only the second person to hold the position in the past half century. With his retirement, let’s reflect on a career that helped shape how scientists understand explosive eruptions, volcanic hazards, and how communities live with active volcanoes.

Born and educated in New Zealand, Houghton established himself as a leading volcanologist at the Institute of Geological and Nuclear Sciences New Zealand before joining the University of Hawaii in 2000. In Hawaii, he became not only a researcher and professor, but also the state volcanologist.

Much of Houghton’s scientific work focused on a deceptively simple question: what can volcanic deposits tell us about the processes that created them? His answer is that the details matter. The textures and densities of erupted volcanic particles, their organization in volcanic deposits, and how they travel in the atmosphere are not just measurements. They are clues to how magma rises, releases gas, interacts with the vent environment, and ultimately erupts.

Houghton also pioneered the application of high-speed, high-resolution imaging of active volcanoes to quantify eruption processes with unprecedented spatial and temporal resolution. The impact of this work is reflected in a research record that includes more than $8 million in research funding since 2000, 291 journal publications, and nearly 20,000 references to his work.

His research challenged the common perception that basaltic volcanoes such as Kilauea and Mauna Loa are relatively simple compared with explosive volcanoes elsewhere in the world. Houghton showed that basaltic eruptions can display a remarkable range of explosive behavior, from exceptionally weak bubble bursts to powerful explosive activity. Basaltic eruptions can shift rapidly and reversibly through a spectrum of styles in a single event, from pulsating gas emission and episodic bursts to Hawaiian fountaining and more explosive eruptions. His work demonstrated that these changes often depend on shallow conduit processes and the vent environment, not just magma composition.

Houghton remained deeply connected to Hawaii’s volcanoes and communities. He worked closely with scientists at the U.S. Geological Survey Hawaiian Volcano Observatory and participated in the scientific response to both the 2008-2018 summit lava lake eruption and the 2018 lower East Rift Zone eruption of Kilauea.

His influence extended far beyond his own research through the generations of students he mentored — 17 doctoral students at the University of Hawaii, four in New Zealand, and two in Iceland — many of whom now work in universities, geological surveys, volcano observatories, and emergency management organizations around the world. During the 2018 eruption, many former and current University of Hawaii students who trained under Houghton played important roles in the response, demonstrating the lasting impact of his commitment to education, mentorship, and public service.

Houghton also refused to separate volcano science from the human world around it. He championed the idea that volcanic crises are not purely scientific events; decisions by residents, emergency managers, planners, and elected officials can strongly influence how communities experience volcanic hazards.

Throughout his career, he advocated for closer collaboration between volcanologists, social scientists, emergency managers, and educators. As science director of the National Disaster Preparedness Training Center at the University of Hawaii, he helped develop training programs connecting volcanic science with emergency preparedness and public safety.

The scientific community recognized Houghton’s contributions through numerous honors. In 2017, he received the Thorarinsson Medal, the highest award in international volcanology. He was also elected a fellow of the American Geophysical Union, the Geological Society of America, and the Royal Society of New Zealand.

In 2025, he was named the world’s second-highest-ranked physical volcanologist based on publications, citations, awards, and impact. He was president of the Geological Society of New Zealand (at age 28!) and deputy secretary-general of the International Association of Volcanology.

Although Houghton has retired from his roles in Hawaii and returned to New Zealand, his connections to volcanology here remain strong. His continuing collaborations, including studies of Kilauea’s ongoing episodic lava-fountaining eruption, ensure that his influence extends well beyond his years at the University of Hawaii. As volcanic activity continues in Hawaii, many of the scientists, ideas, and approaches that guide our understanding of eruptions will continue to reflect the lasting influence of Bruce Houghton.

Volcano Activity Updates

Kilauea has been erupting episodically within the summit caldera since Dec. 23, 2024. Its USGS Volcano Alert level is ADVISORY.

Episode 49 of summit lava fountaining happened for 7.5 hours on June 14. Summit region inflation since the end of episode 49 indicates that another fountaining episode is possible. Models currently indicate that episode 50 is most likely to occur between June 25-27. No unusual activity has been noted along Kilauea’s East Rift Zone or Southwest Rift Zone.

Mauna Loa is not erupting. Its USGS Volcano Alert Level is at NORMAL.

Eight earthquakes were reported felt in the Hawaiian Islands during the past week. Those above magnitude-3 are: a M3.6 earthquake 14 km (8 mi) S of Volcano at 7 km (4 mi) depth on June 24 at 8:29 a.m., a M3.2 earthquake 13 km (8 mi) SSE of Fern Forest at 6 km (3 mi) depth on June 23 at 9 a.m. HST, a M3.8 earthquake 21 km (13 mi) S of Honaunau-Napoopoo at 5 km (3 mi) depth on June 22 at 6:20 a.m., and a M3.1 earthquake 12 km (7 mi) SSE of Volcano at 6 km (3 mi) depth on June 20 at 7:55 p.m.

Please visit HVO’s website for past Volcano Watch articles, Kilauea and Mauna Loa updates, volcano photos, maps, recent earthquake information, and more. Email questions to askHVO@usgs.gov.

Hawaii’s Kaanapali Beach is a famed tourist destination with a problem: The beach itself is gradually disappearing. Now a major debate is underway in Maui about how, or whether, to save it, reports SFGate. Photos from the late 1980s show a much wider beach, one that has narrowed to a sliver in some places. In short, it “still looks spectacular, but there is less of it,” is how the Beat of Hawaii puts it. And it’s not always so spectacular: “Exposed rock and drainage pipes are sometimes seen jutting out from the sand, while orange plastic fencing blocks access to erosion-impacted areas,” per SFGATE. A long-planned state-backed effort to pump offshore sand back onto the beach cleared environmental review, but the state’s land board pulled its funding in 2023 after residents blasted the price tag and raised alarms over marine impacts.

Now hotel and condo owners are reviving the project themselves. Through a new nonprofit, they’re pitching a “nature-based” plan to rebuild the beach to roughly its 1988 width, restore dunes, and plant natives, with applications headed to the state in coming months. Supporters frame it as a way to keep Kaanapali usable and accessible. Opponents like community advocate Kai Nishiki say the real fix is “managed retreat”—moving buildings inland and letting the shoreline migrate naturally. In her view, the real issue is that hotels and condos were built decades ago on dunes too close to the shorefront, without much thought to the long-term ecological impact.

“The problem is the structures, not the beach,” Nishiki tells SFGATE. “The beach is completely fine and healthy if we would just support the coastal ecosystem and support the landward migration of our beaches.” Beachfront owners disagree, and their renewed proposal will trigger another state review and public hearing. In the meantime, “Kaanapali remains a quintessentially beautiful and worthwhile destination, but visitors arriving this year should come with adjusted expectations,” per the Beat of Hawaii.

LOS ANGELES >> Stress on the San Andreas Fault system has reached a 1,000-year high, according to new research from the University of Hawaii.

Higher stress on a fault means the pressure that causes earthquakes is building.

“Our results show that stress levels on multiple fault segments are now at or above the highest values seen in the past millennium and that the region may be capable of a large through-going rupture involving both fault systems,” said lead author Liliane Burkhard, research affiliate in the Hawai‘i Institute of Geophysics and Planetology at the UH-Manoa School of Ocean and Earth Science and Technology and a scientist at the University of Bern, Switzerland.

“We also found that Cajon Pass may act as an ‘earthquake gate:’ sometimes blocking large ruptures from crossing between the faults, and sometimes allowing them to pass through and involve both systems in a single event,” Burkhard said in a UH news release.

Multi-fault ruptures, where earthquakes continue from one fault to another, have occurred in multiple recent earthquakes, including the 2011 Tohoku, Japan, earthquake and became a part of the U.S. Geological Survey’s earthquake forecasting model in 2015.

This type of quake would be possible if the Cajon Pass, which is between the San Bernardino and San Gabriel mountains in Southern California, allows an earthquake to pass through it, meaning rather than affecting the area along one fault line, a quake could continue along a second fault and affect a larger area.

But Kate Scharer, a co-author of the study and a seismologist with the U.S. Geological Survey in Pasadena, said there’s no reason for California residents to be significantly more concerned than they were before hearing about the study.

While the stress has reached a milestone, the pressure was already high and the fault has been overdue for a large earthquake for some time, according to the study.

It has been over 100 years since a major tectonic rupture has affected the greater Los Angeles area, which means stress on the tectonic plates has been building, according to the study.

The 1857 Fort Tejon earthquake was the most recent “big one” to affect Southern California, while the San Jacinto Fault saw moderate earthquakes in 1918, 1968 and 1987, according to the study. A long period without seismic activity “raised concern that the next slip event in this region could be both large and complex,” the study says.

As more time passes, an earthquake becomes more likely because built-up energy needs to be released.

“We know for the southern San Andreas and the San Jacinto fault that they were just a little bit over the average (time between earthquakes) from looking at the geologic record,” Scharer said.

Those two faults are at highest risk for an earthquake because they are the fastest moving, she said.

The study looked at a geologic record of earthquake activity across the past 1,000 years, giving a new perspective on the total stress the San Andreas and San Jacinto fault systems are under. Tectonic plates are always moving and accumulating stress, save for those few seconds where an earthquake is happening.

When an earthquake releases built-up stress from hundreds to thousands of years of an interseismic period, energy is felt in the form of an earthquake, Scharer said.

Earthquake forecast models from the U.S. Geological Survey are “a reminder that damaging earthquakes are inevitable for California,” and the new study highlights just how much stress the fault systems are under as Californians prepare for the “big one,” according to the USGS.

The study’s importance is with the calculations of stress the researchers did. After a geologic record, which looks at prehistoric earthquakes and is assembled by digging trenches across faults and looking at layers that have been offset in the past, is created, the researchers were able to determine that the stress on the San Andreas fault is at a 1,000-year high.

The stress level could influence if the Cajon Pass facilitates an earthquake spreading from one fault to another, or if it stops an earthquake from doing so. When the stress levels on both faults are similar, both faults appear to rupture jointly, according to the study.

Using a physics-based computer model, the researchers found that that the stress that would normally be released in large earthquakes has continued to accumulate and is at unprecedented levels.

The Cajon Pass, the study suggests, could facilitate a joint rupture of both the San Andreas and San Jacinto faults simultaneously, which could be “significantly more damaging than a single-fault event,” affecting densely populated areas including Los Angeles, San Bernardino, Riverside and the Coachella Valley, according to the UH news release.

“This is not a prediction of when an earthquake will happen,” Burkhard said. “However, studies like this are important contributions to national and global earthquake hazard research in that we are using rigorous, quantitative science to better understand the risk facing millions of people. What we can say is that the system is critically stressed, and that physics-based models like this one give us a clearer picture of the range of scenarios we should be prepared for. That information matters for hazard assessments, infrastructure planning, and emergency preparedness.”

Honolulu Star-Advertiser staff contributed to this report.