The Hawaiian Volcano Observatory (HVO) is on a captivating mission to monitor the rapid growth of a new volcanic cone, or 'puʻu', at Kīlauea. But this isn't your average volcano watch—it's a tale of innovation and adaptation in the face of nature's raw power.
Volcano Watch (https://volcanoes.usgs.gov/hvo/hvovolcanowatch.html) is a weekly feature that brings you insights from the front lines of volcanic activity. This week, HVO geologist Natalia Deligne shares the challenges and triumphs of tracking the growth of this new puʻu.
Tephra, including the iconic Pele's hair, has been raining down since the eruption began, but the puʻu's growth became a focal point in late March and early April. Initially, geologists used a road sign as a makeshift gauge, photographing its gradual burial. But by May 11, the sign was almost entirely buried, rendering this method ineffective.
And this is where it gets tricky. The team tried a new approach: garden stakes. They placed 5-foot-tall stakes along the closed road, hoping to measure tephra accumulation like a rain gauge. But nature had other plans. During episodes of lava fountaining, the puʻu grew so rapidly that the stakes were quickly buried, rendering this method impractical.
But here's where it gets controversial... Should they have anticipated this? Was there a better way to measure the tephra accumulation without being overwhelmed by the puʻu's growth? The HVO team had to adapt quickly.
They turned to high-tech solutions, employing handheld GPS instruments to walk transects and collect precise data. This method, though more time-consuming, provided the accuracy needed. Geologists take measurements at multiple locations, including near the peak of the puʻu, which is a challenge due to its changing shape and potential instability.
The GPS instrument must lock onto enough satellites to ensure vertical accuracy, and then it records a data point every second for four minutes. This meticulous process is repeated at each site, making the whole transect a 2-3 hour endeavor. The data is then processed using a nearby permanent GPS monitoring station, resulting in highly accurate elevation measurements.
HVO also utilizes a helicopter-mounted airborne lidar system to scan the entire puʻu in high-resolution 3D. However, processing this data is complex, and attempts to use photogrammetry methods have been unsuccessful due to the puʻu's uniform surface.
The results are astonishing. During lava fountaining episodes, the puʻu can grow by several meters in just a few hours. For instance, at the site of the buried road sign, tephra deposits reached 11 feet thick after episode 23, and episode 24 added a staggering 25.6 feet in just over 7 hours!
The puʻu thrives during high-fountaining episodes, especially those over 1,000 feet tall. Interestingly, when lava fountains are lower, tephra has a harder time reaching the new puʻu. This growth is occurring where visitors once drove around Halemaʻumaʻu, showcasing the dramatic changes Hawaiian volcanoes can bring.
Kīlauea's Current Activity:
- Kīlauea has been erupting episodically within the summit caldera since December 23, 2024, with a current USGS Volcano Alert level of WATCH.
- Episode 37 produced 9 hours of lava fountaining on November 25, and another episode is expected between December 6 and 9.
- Mauna Loa is not erupting, and its alert level is NORMAL.
- A M3.5 earthquake was felt near Pāhala on November 29.
HVO's dedicated monitoring continues, providing valuable insights into the ever-changing world of Hawaiian volcanoes. What do you think of their methods and findings? Are there alternative approaches you'd like to see explored? Share your thoughts in the comments, and stay tuned for more volcanic adventures!
