Some Like It Hot…Really Hot!

Volcanic activity played a major role in shaping the Chico area, and the eruption of Lassen Peak in May of 1915 has a special place in our local history. Researchers from the College of Natural Sciences are taking advantage of our proximity to the Lassen Volcanic Center by engaging students in out-of-classroom field work and research there.

Professors Rachel Teasdale and Dave Brown, along with undergraduate students Mike Parker, Warren Hacker, and Stephanie Mendes (photo at right), have developed techniques to monitor water temperature of volcanic lakes, using test sites in Lassen Volcanic National Park (LVNP), the southernmost volcano of the Cascades Volcanic Arc. The research is based on the idea that water temperature in volcanic lakes and fumaroles will vary with magmatic activity.

Water temperature at Boiling Springs Lake (BSL) and Sulfur Works (SW) is measured by automated data loggers. There is currently no magmatic activity in the Lassen Volcanic National Park, so data recorded by this project provides information about background conditions for the hydrothermal system there. And because there is no continuous monitoring program at any of the other Cascades volcanoes, the research of the CSU, Chico monitoring project may serve as a useful model for other volcanoes.

The research team installed the data loggers at each field site in June 2007. Data is recorded several times per hour and downloaded monthly or bi-monthly. During site visits, pH and CO2 data are also collected. During summer and fall, the research team can download water temperature data and reinstall data loggers for nearly uninterrupted measurements. In winter months, access is more difficult, requiring the research team to snowshoe to both sites.

The data loggers are housed in PVC pipe, submerged with weights, and connected to the shore for retrieval. They record the temperature below the surface of the water and above the muddy lake floor. Measurements can be collected and recorded at any interval, so in summer months, loggers record temperatures every 15 minutes and data is collected monthly; in winter months, it is recorded every 30 minutes and collected less frequently.

As an example of the extreme water temperatures the team is dealing with, water temperature at Sulfur Works has a “baseline” of approximately 77ºC (170ºF). Temperature drops repeatedly by 1–15ºC, generally in the late afternoon (about 2–3 pm) for about three hours, then rises to baseline temperature over the next one to three hours. Water temperature at Boiling Springs Lake fluctuates on an irregular schedule. In summer 2007, temperatures increased approximately 7ºC) for three to five days, and then dropped (about 5ºC) at nearly weekly intervals. Within these fluctuations, temperature increased and decreased multiple times every day (1–3ºC). Water temperature at BSL are generally lower than at SW, ranging from 45ºC to 75ºC (113ºF to 167ºF), with irregular fluctuations. Lake temperature variations are not consistent with daily temperature change, nor do they correlate with air temperature recorded by the California Department Resources at Chester (approximately 20 km from BSL). See graph of water temperature data below.

So far, monitoring the hydrothermal systems at LVNP confirms that the Boiling Springs Lake and Sulphur Works hydrothermal systems are independent from one another, and temperature variations do not correlate with diurnal temperature variations or with air temperature variations. Preliminary measurements indicate pH is higher during wet months and lower in dry months. With only one wet month measurement, this observation is considered preliminary and is the subject of ongoing interpretation.

Mendes (Chemistry), Parker (Geology), and Hacker (Geology) recently presented the results of this work at the Geological Society of America Rocky Mountain/Cordilleran Section Meeting and also presented it at the College of Natural Sciences’ Poster session April 22.

Teasdale and Brown anticipate continuing research in Lassen Volcanic National Park. “Our proximity to Lassen makes this project feasible for the long term,” said Teasdale. “It provides an excellent training ground for fieldwork and high-quality research. Through this research experience, students collaborate with faculty who have diverse backgrounds as well as learn to synthesize their own backgrounds in geology and chemistry in order to conduct research important to our region.”

—Kathleen McPartland with Rachel Teasdale, Natural Sciences

Research in Lassen Photos