Thursday, January 26, 2012

[Geology2] Halema‘uma‘u Overlook Vent

Link to latest web cam photo below

This image is from a temporary research camera positioned at the Halemaʻumaʻu Overlook Vent.

January 24, 2011: A wider lens was added to the webcam in order to capture the full range of vertical lava movement. The view now includes the floor of Halemaʻumaʻu Crater in the upper part of the frame.

December 14, 2010: Because the lava high stands in the Overlook vent have been well above the field of view of the Webcam, the camera was zoomed all the way out and the back leg of the tripod was shortened to tilt the camera back, thus minimizing the amount of foreground in the picture. These changes should allow more of the lava surface to be seen even during the high lava stands.

June 18, 2010: Since late January, the view has included a crusted, circulating lava surface whose level has risen to about 200 m below the camera site, 115 m below the Halemaʻumaʻu Crater floor. The gray scale image indicates that the camera is in "night vision" mode which allows better visibility through fume than the normal color visual mode. 

September 11, 2009: This camera was replaced with a higher-resolution model that is also low-light sensitive, producing a clearer view of activity on the floor of the Halemaʻumaʻu cavity.  The floor of the cavity is about 290 m below the camera site.  This month, an active spattering hole on the floor of the cavity has been visible at night towards the right side of the image.  During the day, only thick fume is visible.  

May 8, 2009: This camera was repositioned to look straight down into the vent cavity. The camera records color during the day (mostly fume) and light intensity at night. In early June, the best views of the circulating lava deep below the Halemaʻumaʻu Crater floor were available around dusk and dawn.

Laser-ranging measurements in June, 2009, determined that the lava surface is about 290 m (950 ft) below the Halemaʻumaʻu Crater rim (where this webcam is installed) and 205 m (670 ft) below the crater floor. Mahalo to Todd Ericson, University of Hawai`i at Manoa, for helping us with these measurements.

The webcam is operational 24/7 and faithfully records the dark of night if there are no sources of incandescence or other lights.  At times, clouds and rain obscure visibility. The camera is subject to sporadic breakdown, and may not be repaired immediately. The camera is observing an area that is off-limits to the general public because of significant volcanic hazards.

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