South winds on Dec. 17 blow the gas plume from the Halemaumau Overlook vent across Kilauea’s caldera toward Volcano Village. A Webcam located directly above the vent on the crater rim captures much of the activity, especially during nighttime, when the plume is not too thick. Images are uploaded at least every 5 minutes during the day and 2 minutes during the night to the following Web page: http://volcanoes.usgs.gov/hvo/cams/HMcam/ (Photo courtesy of HVO)

(Volcano Watch is a weekly article written by scientists at the U.S. Geological Survey’s Hawaiian Volcano Observatory.)

Clear weather and an active lava column in the Halemaumau Overlook vent this week is brightening the nighttime glow at the summit of Kilauea just in time for the holiday season. The glow is especially notable from the Jaggar Museum viewing area in Hawaii Volcanoes National Park, located only 1.2 mile from the vent.

Activity in the summit vent is following a pattern observed many times in 2009. Early this past week, lava in the vent went through a series of impressive filling and draining cycles that lit up the base of the gas plume with incandescent glow. One filling and draining cycle took about 5 minutes to complete.

At this high stand of lava, small plates of cooled crust would form around the edges of the pond. As the lava flowed back into the opening during the drainback phase of the cycle, the cooled crust pieces moved toward the center of the opening and disappeared down into the vent. The draining created a chaotic area of spattering at the center of the pond.

Similar to earlier episodes, the draining phase happened faster than the filling phase. During both filling and draining the sounds of lava sloshing and spattering were quite loud, and, when the draining was finished, there was a quiet period lasting tens of seconds. During this quiet period the vent went fairly dark compared to the very bright levels during active filling and draining.

This activity was captured on video by scientists making routine observations and measurements early this past week from directly above the Overlook vent, and can be viewed on the Web site of the Hawaiian Volcano Observatory.

For images and video of Kilauea’s activity, visit the following Web page: http://hvo.wr.usgs.gov/kilauea/update/images.html

The vent continues to release between 700 and 1,000 tonnes of sulfur dioxide gas each day as the height of the lava column in the vent remains more than 660 feet below the foor of Halemaumau Crater and 950 feet below the crater rim.

The nighttime glow from the Overlook Vent varies considerably from hour to hour and week to week as the height of the lava column changes and the size of the opening above the column is altered by the accumulation of cooled lava and spatter and collapse of the material into the churning lava.

Thus, at the time of this writing (Wednesday evening), the glow was a little subdued compared to earlier in the week, but beautiful at sunset nonetheless! Be sure to bring warm clothes if you plan to visit the Jaggar Museum at night!