SUBHEAD: HVO geologist estimates the lava lake had risen over 260 feet, since November.
By Peter Sur on 13 February 2011 for the Tribune-Herald - (http://www.hawaiitribune-herald.com/articles/2011/02/13/local_news/local01.txt)
Image above: Painting of Halemaumau Crater by Diane Burko (2000). From (http://www.dianeburko.com/work/paintings/volcanoes/hawaii/halemaumau_crater1.html).
[IB Editor's note: In the last few years volcanic activity on the Big Island has increased vog (volcanic smog) frequency and volume. Vog includes sulfuric acid mixed with dust. As a result many people sensitive to vog have suffered sinus, throat and bronchial problems as far away as here on Kauai. This is not be something like a passing weather condition. It is a geological phenomena. It could go away tomorrow, but could easily last a hundred years. If there is increased volcanic activity we will have more voggy days on the Garden Island.]
The lava lake at the summit of Halema'uma'u crater has been rising gradually in the last few months. It's within 235 feet of Halema'uma'u floor. One of Hawaii's hidden wonders, a circulating body of molten lava some 460 feet in diameter, rises and falls at the bottom of a pit in the floor of Halema'uma'u, within the Kilauea caldera. The lava was first seen in November 2009, lurking in a hole 660 feet below the surface of the old crater, fluctuating in height.
Since that time, the lake has grown in size and risen to within 235 feet of the crater floor as of Saturday morning. It is not visible from the overlook at the Thomas A. Jaggar Museum, but volcanologists are able to watch it through a webcam perched on the rim of the crater. Much of the rise has taken place within the past several days. Wednesday, the lava lake was some 340 feet below the floor of Halema'uma'u.
Thursday, it topped 300 feet as Kilauea volcano shivered with nearly two dozen small earthquakes. By Friday, it had risen to within 260 feet of the crater floor. "We've seen since November, just sort of a gradual increase in the height of the lava lake," said Hawaiian Volcanoes Observatory geologist Janet Babb. "Over the last four months or so, there's just sort of an overall increase in height." HVO geologist Tim Orr on Friday estimated the lake had risen at least 80 meters, or 262 feet, since November. "It has come up pretty significantly," Orr said.
As is the norm with Kilauea, the significance of the rising lava lake is unknown. It's possible that the lava could spill out of the pit and on to the crater floor, though this might take months to happen. It's possible that pressure on the magma system could force an intrusion somewhere on the East Rift Zone. It's equally possible that nothing will happen. "Magma is building up at the summit. There is pressure on the system," Orr said. This could be due to an increase in the magma supply or a backing up of the magma in the East Rift Zone. Sensitive monitoring instruments have followed the steadily inflating volcano for months; the pace picked up near Halema'uma'u in November.
Since the middle of last year, GPS receivers positioned on opposite sides of Kilauea's caldera have moved nearly 4 inches apart to accommodate the increased amount of magma. "Clearly some things are changing, but what this leads to, we don't know," Orr said. HVO seismologists are also watching an increased number of earthquakes in the upper East Rift Zone. They are careful not to call it an earthquake swarm; that would imply an imminent outbreak of lava.
According to Jim Kauahikaua, HVO's scientist-in-charge, the current increase in seismicity resembled in some ways the prelude to the intrusion and brief eruption on June 17, 2007, in a remote section of Hawaii Volcanoes National Park. But there were also several similar seismic episodes when nothing happened, so it's hard to say what will happen. The largest earthquake so far struck at 8:30 a.m. Thursday. It measured magnitude 3.8 and was centered three miles southeast of Kilauea's summit.
Magma upwelling from deep within the Earth surfaces at the lava lake and then passes through an underground conduit in the East Rift Zone, where it erupts again near the Pu'u 'O'o vent on its way to the sea.
Image above: Lava rising in Halemaumau Crater. From original article.
.
By Peter Sur on 13 February 2011 for the Tribune-Herald - (http://www.hawaiitribune-herald.com/articles/2011/02/13/local_news/local01.txt)
Image above: Painting of Halemaumau Crater by Diane Burko (2000). From (http://www.dianeburko.com/work/paintings/volcanoes/hawaii/halemaumau_crater1.html).
[IB Editor's note: In the last few years volcanic activity on the Big Island has increased vog (volcanic smog) frequency and volume. Vog includes sulfuric acid mixed with dust. As a result many people sensitive to vog have suffered sinus, throat and bronchial problems as far away as here on Kauai. This is not be something like a passing weather condition. It is a geological phenomena. It could go away tomorrow, but could easily last a hundred years. If there is increased volcanic activity we will have more voggy days on the Garden Island.]
The lava lake at the summit of Halema'uma'u crater has been rising gradually in the last few months. It's within 235 feet of Halema'uma'u floor. One of Hawaii's hidden wonders, a circulating body of molten lava some 460 feet in diameter, rises and falls at the bottom of a pit in the floor of Halema'uma'u, within the Kilauea caldera. The lava was first seen in November 2009, lurking in a hole 660 feet below the surface of the old crater, fluctuating in height.
Since that time, the lake has grown in size and risen to within 235 feet of the crater floor as of Saturday morning. It is not visible from the overlook at the Thomas A. Jaggar Museum, but volcanologists are able to watch it through a webcam perched on the rim of the crater. Much of the rise has taken place within the past several days. Wednesday, the lava lake was some 340 feet below the floor of Halema'uma'u.
Thursday, it topped 300 feet as Kilauea volcano shivered with nearly two dozen small earthquakes. By Friday, it had risen to within 260 feet of the crater floor. "We've seen since November, just sort of a gradual increase in the height of the lava lake," said Hawaiian Volcanoes Observatory geologist Janet Babb. "Over the last four months or so, there's just sort of an overall increase in height." HVO geologist Tim Orr on Friday estimated the lake had risen at least 80 meters, or 262 feet, since November. "It has come up pretty significantly," Orr said.
As is the norm with Kilauea, the significance of the rising lava lake is unknown. It's possible that the lava could spill out of the pit and on to the crater floor, though this might take months to happen. It's possible that pressure on the magma system could force an intrusion somewhere on the East Rift Zone. It's equally possible that nothing will happen. "Magma is building up at the summit. There is pressure on the system," Orr said. This could be due to an increase in the magma supply or a backing up of the magma in the East Rift Zone. Sensitive monitoring instruments have followed the steadily inflating volcano for months; the pace picked up near Halema'uma'u in November.
Since the middle of last year, GPS receivers positioned on opposite sides of Kilauea's caldera have moved nearly 4 inches apart to accommodate the increased amount of magma. "Clearly some things are changing, but what this leads to, we don't know," Orr said. HVO seismologists are also watching an increased number of earthquakes in the upper East Rift Zone. They are careful not to call it an earthquake swarm; that would imply an imminent outbreak of lava.
According to Jim Kauahikaua, HVO's scientist-in-charge, the current increase in seismicity resembled in some ways the prelude to the intrusion and brief eruption on June 17, 2007, in a remote section of Hawaii Volcanoes National Park. But there were also several similar seismic episodes when nothing happened, so it's hard to say what will happen. The largest earthquake so far struck at 8:30 a.m. Thursday. It measured magnitude 3.8 and was centered three miles southeast of Kilauea's summit.
Magma upwelling from deep within the Earth surfaces at the lava lake and then passes through an underground conduit in the East Rift Zone, where it erupts again near the Pu'u 'O'o vent on its way to the sea.
Image above: Lava rising in Halemaumau Crater. From original article.
.
No comments :
Post a Comment