December 15. 2014 Hawai'i Hot Lava

PAHOA, Hawaii —Lava flow continued to flow toward a business center in Pahoa on the Big Island Sunday

The Hawaii County Civil Defense reported that the leading edge of the flow on Kilauea Volcano was about 1.4 miles upslope from the intersection of Pahoa Village Road and Highway 130 in the vicinity of Pahoa Marketplace.
The Hawaiian Volcano Observatory reported that the flow moved about 300 yards since Saturday.
The flow is following what geologists refer to as a steepest descent path or a topographical low in the terrain.
The flow, which began June 27, is being fed through a lava tube from Pu’u O’o crater.
Aerial footage released Friday showed the flow making its way through forest land upslope from Pahoa.
Geologists reported a weak breakout in the tube farther upslope about 1.6 miles from the source.

Pahoa Marketplace still in lava's path

PAHOA — The June 27 lava flow is continuing on its path toward Pahoa Marketplace.

Hawaiian Volcano Observatory officials say the flow still is advancing toward the shopping center and is expected to stay on that route as it passes through an area where two lines of steepest descent nearly converge.

“That’s what we would expect at this point unless something changes,” said Janet Babb, HVO spokeswoman.

“… Our expectation is it will continue to follow that flow path.”

The flow advanced 300 yards between Tuesday morning and Wednesday morning and was about 2 miles from the shopping area, according to Hawaii County Civil Defense.

It was about 50 to 75 yards wide at its front, said Civil Defense Administrator Darryl Oliveira.

Oliveira said outreach with businesses in the area is continuing.

“We are trying to maintain as close communication with them as possible without creating additional fear and anxiety,” he said.

- See more at: http://hawaiitribune-herald.com/news/local-news/pahoa-marketplace-still-lava-flow-s-path#sthash.IFSIDR2t.dpuf

Kilauea Status Report for December 8, 2014

Recent Kilauea Status Reports, Updates, and Information Releases

HAWAIIAN VOLCANO OBSERVATORY DAILY UPDATE
U.S. Geological Survey Monday, December 8, 2014 9:54 AM HST (Monday, December 8, 2014 19:54 UTC)

This report on the status of Kilauea volcanic activity, in addition to maps, photos, and Webcam images (available at http://hvo.wr.usgs.gov/activity/kilaueastatus.php), was prepared by the USGS Hawaiian Volcano Observatory (HVO). All times are Hawai`i Standard Time. 

KILAUEA VOLCANO (VNUM #332010) 
19°25'16" N 155°17'13" W, Summit Elevation 4091 ft (1247 m)
Current Volcano Alert Level: WARNING
Current Aviation Color Code: ORANGE

Activity Summary: Kīlauea Volcano continues to erupt at its summit and within its East Rift Zone. A narrow lobe of lava west of the flow field below the crack system remains active but advanced little since yesterday. The leading edge of this lobe is approximately 3.9 km (2.4 miles) above the intersection of Pāhoa Village Road and Highway 130, near the Pahoa Marketplace. There was no significant change in activity at the summit.

June 27th Lava Flow Observations: HVO is monitoring a narrow flow lobe that branches off the west edge of the flow field below the crack system. A Civil Defense overflight on Sunday found that flow had widened but had advanced very little since Saturday. The leading edge of the flow was still about 3.9 km (2.4 mi) upslope from the intersection of Pāhoa Village Road and Highway 130, near the Pahoa Marketplace. The front of the flow is in area where several lines of steepest descent nearly converge due to flat topography and is probably the main factor in the decline of the advance rate. Until the flow passes this area of flat topography, the future flow path is uncertain. The flow front has also entered a burn scar which has significantly reduced the amount of smoke seen from the flow front in our webcams. 

Puʻu ʻŌʻō Observations: There was weak deflation at Puʻu ʻŌʻō over the past 24 hours. All other monitoring data indicate no significant changes at Puʻu ʻŌʻō. Seismic tremor is low and steady, and webcams revealed no strong variations in the pattern of glow from degassing vents or the configuration of the crater floor. GPS-measured deformation across the cone has shown neither extension nor contraction since July. The most recent measurement of sulfur dioxide emissions from the East Rift Zone was about 250 tonnes per day on November 26, 2014.

Summit Observations: There was no significant ground tilt at the summit since midday yesterday. The summit lava lake showed the usual fluctuations associated with changes in spattering behavior, which are also manifested as variations in tremor amplitudes. Small amounts of particulate material were carried aloft by the plume. The average emission rate of sulfur dioxide was 4,300 tonnes/day for the week ending on December 2 (see caveat below).

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Sulfur Dioxide Emission Rate estimation caveat: Starting in 2014, we report the emission rate estimated by a new, more accurate method. The numbers increase by a factor of 2-4 but the actual emission rate has not changed. For more on this reporting change, please read http://hvo.wr.usgs.gov/volcanowatch/view.php?id=207

Background:
Summit The summit lava lake is within an elliptical crater (unofficially called the Overlook crater), which has dimensions of approximately 160 m (520 ft) by 210 m (690 ft), inset within the eastern portion of Halemaʻumaʻu Crater. The lake level has varied from about 25 m to more than 200 m (out of sight) below the floor of Halemaʻumaʻu Crater. The Overlook crater has been more-or-less continuously active since it opened during a small explosive event on March 19, 2008. The lake level responds to summit tilt changes with the lake generally receding during deflation and rising during inflation. Since 2013, the lava level has been typically between 30 m (100 ft) and 60 m (200 ft) below the floor of Halemaʻumaʻu Crater. Small collapses in the Overlook crater are common, and over time have resulted in a gradual enlargement of the Overlook crater. The ambient SO2 concentrations near the vent vary greatly, but are persistently higher than 10 ppm and frequently exceed 50 ppm (upper limit of detector) during moderate trade winds. The gas plume typically includes a small amount of ash-sized tephra (mostly fresh spatter bits and Pele's hair from the circulating lava lake). The heaviest pieces are deposited onto nearby surfaces while the finer bits can be carried several kilometers before dropping out of the plume. 

East Rift Zone vents and flow field The eruption in Kīlauea's middle East Rift Zone started with a fissure eruption on January 3, 1983, and continued with few interruptions at Puʻu ʻŌʻō Cone, or temporarily from vents within a few kilometers to the east or west. A fissure eruption on the upper east flank of Puʻu ʻŌʻō Cone on Sept. 21, 2011, drained the lava lakes and fed a lava flow (Peace Day flow) that advanced southeast through the abandoned Royal Gardens subdivision to the ocean within Hawaiʻi Volcanoes National Park in early December 2011. The flows stalled and re-entered the ocean starting on November 24, 2012, until activity started to decline and the ocean entry ceased in August 20, 2013; the flow was dead by early November, 2013. The Kahaualeʻa flow, which started from the spatter cone/lava lake at the northeast edge of the Puʻu ʻŌʻō crater floor in mid-January 2013 was dead by late April, but a new flow (informally called Kahaualeʻa 2) became active in the same area in early May 2013, waxing with inflation and waning with deflation. The Kahaualeʻa 2 flow died following the onset of a new breakout from the northeast flank of Puʻu ʻŌʻō on June 27, 2014. The June 27th flow advanced to the northeast, confined to old grounds cracks for part of its length, and has been slowly approaching the town of Pāhoa.

Hazard Summary:
East Rift Zone vents and flow field Lava flows from the June 27 breakout have advanced into Pāhoa and may threaten residential areas depending on their level of activity and advance rate. Near-vent areas could erupt or collapse without warning with spatter and/or ash being wafted within the gas plume. In addition, potentially-lethal concentrations of sulfur dioxide gas may be present within 1 km downwind of vent areas. Active lava flows within forested areas can produce methane blasts capable of propelling rocks and other debris into the air. All recently active lava flows are within Hawaiʻi Volcanoes National Park and adjacent State land managed by the Department of Land and Natural Resources or the Office of Hawaiian Affairs.

Kīlauea Crater Ash and Pele's hair can be carried several kilometers downwind, and potentially-lethal concentrations of sulfur dioxide can be present within 1 km downwind.

Viewing Summary:
East Rift Zone flow field The June 27th lava flow is currently within the Kahaualeʻa Natural Area Reserve, which has been closed by the Hawaii State Department of Natural Land and Resources (DLNR) due to the ongoing volcanic hazards (http://dlnr.hawaii.gov/ecosystems/nars/reserves/hawaii-island/kahaualea/), and the Wao Kele o Puna Forest Reserve, also closed by DLNR and the Office of Hawaiian Affairs (http://dlnr.hawaii.gov/blog/2014/09/12/nr14-113/). According to the Hawaii County Civil Defense website (http://www.hawaiicounty.gov/active-alerts/): "The public is reminded that the flow is not visible and cannot be accessed from any public areas." 

Puʻu ʻŌʻō Cone and Kīlauea Crater These areas are within Hawaiʻi Volcanoes National Park; Park access and viewing information can be found at http://www.nps.gov/havo/planyourvisit/lava2.htm. 

Definitions of Terms Used:

ash: tephra less than 2 mm (5/64 inches) in size.

CD: Hawai`i County Civil Defense

composite seismic events: is a seismic signal with multiple distinct phases that has been recorded frequently at HVO from the Halema`uma`u Overlook vent area since its explosive opening in March, 2008. For the composite events recorded at Halema`uma`u, we typically see an initial high frequency vibration lasting for a few seconds that have been correlated with rockfalls. This is followed by about 30 seconds of a long-period (LP) oscillation with an approximately 2- to 3-second period. The final phase of the signal is several minutes of a very-long-period (VLP) oscillation with an approximately 25- to 30-second period. The LP signals are interpreted to be from the uppermost portion of the conduit and VLP signals are interpreted to be fluid passing through a deep constriction in the conduit through which lava rises to the pond surface we see in the webcam.

DI tilt event: DI is an abbreviation for 'deflation-inflation' and describes a geophysical event of uncertain volcanic significance. DI events are recorded by tiltmeters at Kilauea summit as an abrupt deflation of up to a few microradians in magnitude lasting several hours (weak DI events) to 2-3 days (strong DI events) followed by an abrupt inflation of approximately equal magnitude. The tilt events are usually accompanied by an increase in summit tremor during the deflation phase. A careful analysis of these events suggests that they may be related to changes in magma supply to a storage reservoir at less than 1 km depth, just east of Halema`uma`u crater. Usually, though not always, these changes propagate through the magma conduit from the summit to the east rift eruption site, as many of the DI events at Kilauea summit are also recorded at a tiltmeter at Pu`u `O`o delayed by several hours. DI events often correlate with lava pulses and/or pauses in the eruption at the Pu`u `O`o/Peace Day vents.

glow: light from an unseen source; indirect light.

Halema`uma`u Overlook vent: has been difficult to describe concisely. The vent is actually a pit, or crater, in the floor of the larger Halema`uma`u Crater which is, in turn, in the floor of the larger Kilauea caldera or crater - a crater within a crater within a crater. It is easiest to describe as a pit inset within the floor of a crater within a caldera. The pit is about 160 m (525 ft) in diameter at the Halema`uma`u Crater floor, is about 50 m in diameter at a depth of 200 m (660 ft) below the Halema`uma`u Crater floor. From November, 2009, to now, a lava pond surface has been visible in this pit.

incandescence: the production of visible light from a hot surface. The term also refers to the light emitted from a hot surface. The color of the light is related to surface temperature. Some surfaces can display dull red incandescence at temperatures as low as 430 degrees Centigrade (806 degrees Fahrenheit). By contrast, molten lava displays bright orange to orange-yellow light from surfaces that are hotter than 900 degrees C (1,650 degrees F).

LPs: - Long Period (LP) events refer to earthquakes that have a lower frequency or tone than typical earthquakes and are usually attributed to the resonance of fluid- and gas-filled conduits, cracks and/or chambers. Because of their association with fluids and gases, LP earthquakes in the vicinity of volcanoes can be useful for monitoring purposes. At other volcanoes LP earthquakes are also known as low-frequency earthquakes, tornillos or B-type earthquakes.

mauka, makai: Hawaiian terms for directions relative to the coast - makai or ma kai (toward the coast) and mauka or ma uka (toward the highlands or away from the coast).

microradian: a measure of angle equivalent to 0.000057 degrees.

pali: Hawaiian term for cliff or precipice.

rise/fall events: one of the episodic behaviors exhibited by the summit lava lake starting in 2009. An event starts with a rise in lava level, a decrease in high-frequency summit tremor amplitude, a decrease or total stoppage of spattering, and a small decrease in tilt. After a period of minutes to hours, the lava will abruptly drain back to its previous level amidst resumed vigorous spattering, seismic tremor amplitude will increase for a short time (a seismic tremor burst) before resuming background levels, and summit tilt will return to its previous level. Gas emissions decrease significantly during the high lava stand (the plume gets wispy), and resume during its draining phase. Taken together, the geophysical characteristics suggest that, during the high lava stand, lava is puffed up with gas trapped under the lava lake crust. 

seismic tremor dropout: these behaviors are identical to rise/fall events except that the lava lake level doesn't rise or fall significantly. High-frequency seismic tremor, gas emissions, and spattering decrease abruptly during a dropout. A dropout can end with a burst of seismic tremor and a significant pulse of gas emissions.

tephra: all material deposited by fallout from an eruption-related plume, regardless of size.

tonne (t): metric unit equal to 1,000 kilograms, 2,204.6 lbs, or 0.984 English tons.

More definitions with photos can be found at http://volcanoes.usgs.gov/images/pglossary/index.php.

Additional Information: 
For a definition of volcano alert levels and aviation color codes: http://volcanoes.usgs.gov/activity/alertsystem/index.php

Maps, photos, Webcam views, and other information about Kilauea Volcano are available at http://volcanoes.usgs.gov/hvo/activity/kilaueastatus.php. A daily update summary is available by phone at (808) 967-8862.

A map with details of earthquakes located within the past two weeks can be found at http://hvo.wr.usgs.gov/seismic/volcweb/earthquakes/

HVO Contact Information: askHVO@usgs.gov

The Hawaiian Volcano Observatory is one of five volcano observatories within the U.S. Geological Survey and is responsible for monitoring volcanoes and earthquakes in Hawai`i.

Kilauea Activity Update

Kīlauea Activity Update

The lava flow from Puʻu ʻŌʻō that began on June 27, 2014, remains active and is advancing across State land east of the Wao Kele O Puna Forest Reserve. As of Thursday, December 4, the tip of the flow was about 3.9 km (2.4 mi) upslope from the intersection of Highway 130 and Pāhoa Village Road near the Pāhoa Marketplace. There was no significant change in activity at Puʻu ʻŌʻō.

The level of the summit lava lake within Halemaʻumaʻu Crater fell during the early part of the week, mimicking deflation at Kīlauea’s summit, but was rising again by December 3, in concert with summit inflation. As of Thursday morning, December 4, the lava lake was about 64 m (210 ft) below the rim of the Overlook crater, up from a low of 70 m (230 ft) measured two days earlier.

No earthquakes were reported felt in Hawaii during the past week.

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Visit our Web site (hvo.wr.usgs.gov) for detailed Kīlauea and Mauna Loa activity updates, recent volcano photos, recent earthquakes, and more; call (808) 967-8862 for a Kīlauea activity summary; email questions to askHVO@usgs.gov.

What's going on? Withdrawal of magma or the movement of Kilauea's south flank or both?

The ongoing subsidence of the summit is thought to result mainly from magma movement out of the summit reservoir and into the east rift zone at a faster rate than it is being supplied from below (the hot spot beneath the Big Island). But other deformation surveys show that the subsidence has also been accompanied by the spreading or widening of the summit area and deformation of the rift zones. This broader region of deformation has led some scientists to suggest that another process--the movement of the volcano's south flank--may account for some of the subsidence.

Although the summit area of Kilauea has steadily subsided since the beginning of the Pu`u `O`o-Kupaianaha eruption, it has been subsiding and spreading (widening) at varying rates since a magnitude 7.2 earthquake occurred 9 to 10 km beneath the south flank of Kilauea on November 29, 1975. The earthquake probably originated as movement of the south flank along a broad slip surface defined by the boundary between the volcano and the underlying sea floor. Parts of the south flank moved suddenly seaward 3 to 8 m and subsided 1 to 3.5 m during the earthquake.

Scientists have long measured the seaward movement Kilauea's south flank and noticed correlations with intrusions of magma into the volcano's rift zones, eruptions, and large earthquakes. Three main hypotheses have been proposed to explain the fundamental cause of the south flank's mobility:

1. repeated forceful intrusion of magma into Kilauea's rift zones, which forces the volcano apart
2. gravitational settling of the entire south flank due to its enormous mass
3. the presence of a deep magma reservoir system beneath the summit and rift zones

Thus, in addition to the withdrawal of magma from the summit reservoir since 1983, part of the subsidence and spreading at the summit may also be related to continued movement of the south flank since the 1975 earthquake.

Deformation of the summit, rift zones, and south flank of Kilauea continues to be a major focus of the monitoring program at the Hawaiian Volcano Observatory. Ongoing research into the underlying causes of the volcano's movement is sure to improve our understanding of how Kilauea responds to gravity and its magma reservoir system.

 The URL of this page is http://hvo.wr.usgs.gov/howwork/subsidence/ 

Contact: hvowebmaster@usgs.gov

Hawai'i Hot Lava Video

December 3, 2014 Hawai'i Hot Lava Update

Recent Kilauea Status Reports, Updates, and Information Releases

HAWAIIAN VOLCANO OBSERVATORY DAILY UPDATE
U.S. Geological Survey Wednesday, December 3, 2014 8:45 AM HST (Wednesday, December 3, 2014 18:45 UTC)

This report on the status of Kilauea volcanic activity, in addition to maps, photos, and Webcam images (available at http://hvo.wr.usgs.gov/activity/kilaueastatus.php), was prepared by the USGS Hawaiian Volcano Observatory (HVO). All times are Hawai`i Standard Time. 

KILAUEA VOLCANO (VNUM #332010) 
19°25'16" N 155°17'13" W, Summit Elevation 4091 ft (1247 m)
Current Volcano Alert Level: WARNING
Current Aviation Color Code: ORANGE

Activity Summary: Kīlauea Volcano continues to erupt at its summit and within its East Rift Zone. A finger of lava has broken away from the west edge of the flow field below the crack system continued to move to the north. The leading edge of this finger is approximately 4 km (2.5 miles) above the intersection of Pāhoa Village Road and Highway 130, near the Pahoa Marketplace. At the summit there was a brief period of inflation followed by deflation, which continues.

June 27th Lava Flow Observations: HVO is monitoring a narrow finger of lava that has broken away from the west edge of the flow field below the crack system and that is moving to the north at rates of several hundred meters per day. Webcam imagery of smoke from burning vegetation at the flow front indicates that the flow continues to advance and satellite imagery from the morning of December 3 located the leading edge as being approximately 4 km (2.5 mi) above the intersection of Pāhoa Village Road and Highway 130, near the Pahoa Marketplace. The flow front position is essentially the same as that reported by Civil Defense overflight Wednesday morning. The flow is approximately 500 m from a point where several lines of steepest descent nearly converge due to flat topography. Until the flow passes this area of flat topography, the future flow path is uncertain. 

Puʻu ʻŌʻō Observations: Deflation of Puʻu ʻŌʻō continues, presumably as a consequence of the DI event that is ongoing at the summit. A minor inflection in tilt is correlated with rainfall at Puʻu ʻŌʻō. All other monitoring data indicate no significant changes at Puʻu ʻŌʻō. Seismic tremor is low and steady, and webcams revealed no strong variations in the pattern of glow from degassing vents or the configuration of the crater floor. GPS-measured deformation across the cone has shown neither extension nor contraction since July. The most recent measurement of sulfur dioxide emissions from the East Rift Zone was about 250 tonnes per day on November 26, 2014.

Summit Observations: DI deflation changed to inflation in the afternoon of December 2. Inflation only amounted to about 1 microradian before deflation began at about 3 AM on December 3. The summit lava lake showed the usual fluctuations associated with changes in spattering behavior, which are also manifested as variations in tremor amplitudes. Small amounts of particulate material were carried aloft by the plume. The average emission rate of sulfur dioxide was 6,900 tonnes/day for the week ending on November 25 (see caveat below).

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Sulfur Dioxide Emission Rate estimation caveat: Starting in 2014, we report the emission rate estimated by a new, more accurate method. The numbers increase by a factor of 2-4 but the actual emission rate has not changed. For more on this reporting change, please read http://hvo.wr.usgs.gov/volcanowatch/view.php?id=207

Background:
Summit The summit lava lake is within an elliptical crater (unofficially called the Overlook crater), which has dimensions of approximately 160 m (520 ft) by 210 m (690 ft), inset within the eastern portion of Halemaʻumaʻu Crater. The lake level has varied from about 25 m to more than 200 m (out of sight) below the floor of Halemaʻumaʻu Crater. The Overlook crater has been more-or-less continuously active since it opened during a small explosive event on March 19, 2008. The lake level responds to summit tilt changes with the lake generally receding during deflation and rising during inflation. Since 2013, the lava level has been typically between 30 m (100 ft) and 60 m (200 ft) below the floor of Halemaʻumaʻu Crater. Small collapses in the Overlook crater are common, and over time have resulted in a gradual enlargement of the Overlook crater. The ambient SO2 concentrations near the vent vary greatly, but are persistently higher than 10 ppm and frequently exceed 50 ppm (upper limit of detector) during moderate trade winds. The gas plume typically includes a small amount of ash-sized tephra (mostly fresh spatter bits and Pele's hair from the circulating lava lake). The heaviest pieces are deposited onto nearby surfaces while the finer bits can be carried several kilometers before dropping out of the plume. 

East Rift Zone vents and flow field The eruption in Kīlauea's middle East Rift Zone started with a fissure eruption on January 3, 1983, and continued with few interruptions at Puʻu ʻŌʻō Cone, or temporarily from vents within a few kilometers to the east or west. A fissure eruption on the upper east flank of Puʻu ʻŌʻō Cone on Sept. 21, 2011, drained the lava lakes and fed a lava flow (Peace Day flow) that advanced southeast through the abandoned Royal Gardens subdivision to the ocean within Hawaiʻi Volcanoes National Park in early December 2011. The flows stalled and re-entered the ocean starting on November 24, 2012, until activity started to decline and the ocean entry ceased in August 20, 2013; the flow was dead by early November, 2013. The Kahaualeʻa flow, which started from the spatter cone/lava lake at the northeast edge of the Puʻu ʻŌʻō crater floor in mid-January 2013 was dead by late April, but a new flow (informally called Kahaualeʻa 2) became active in the same area in early May 2013, waxing with inflation and waning with deflation. The Kahaualeʻa 2 flow died following the onset of a new breakout from the northeast flank of Puʻu ʻŌʻō on June 27, 2014. The June 27th flow advanced to the northeast, confined to old grounds cracks for part of its length, and has been slowly approaching the town of Pāhoa.

Hazard Summary:
East Rift Zone vents and flow field Lava flows from the June 27 breakout have advanced into Pāhoa and may threaten residential areas depending on their level of activity and advance rate. Near-vent areas could erupt or collapse without warning with spatter and/or ash being wafted within the gas plume. In addition, potentially-lethal concentrations of sulfur dioxide gas may be present within 1 km downwind of vent areas. Active lava flows within forested areas can produce methane blasts capable of propelling rocks and other debris into the air. All recently active lava flows are within Hawaiʻi Volcanoes National Park and adjacent State land managed by the Department of Land and Natural Resources or the Office of Hawaiian Affairs.

Kīlauea Crater Ash and Pele's hair can be carried several kilometers downwind, and potentially-lethal concentrations of sulfur dioxide can be present within 1 km downwind.

Viewing Summary:
East Rift Zone flow field The June 27th lava flow is currently within the Kahaualeʻa Natural Area Reserve, which has been closed by the Hawaii State Department of Natural Land and Resources (DLNR) due to the ongoing volcanic hazards (http://dlnr.hawaii.gov/ecosystems/nars/reserves/hawaii-island/kahaualea/), and the Wao Kele o Puna Forest Reserve, also closed by DLNR and the Office of Hawaiian Affairs (http://dlnr.hawaii.gov/blog/2014/09/12/nr14-113/). According to the Hawaii County Civil Defense website (http://www.hawaiicounty.gov/active-alerts/): "The public is reminded that the flow is not visible and cannot be accessed from any public areas." 

Puʻu ʻŌʻō Cone and Kīlauea Crater These areas are within Hawaiʻi Volcanoes National Park; Park access and viewing information can be found at http://www.nps.gov/havo/planyourvisit/lava2.htm. 

Definitions of Terms Used:

ash: tephra less than 2 mm (5/64 inches) in size.

CD: Hawai`i County Civil Defense

composite seismic events: is a seismic signal with multiple distinct phases that has been recorded frequently at HVO from the Halema`uma`u Overlook vent area since its explosive opening in March, 2008. For the composite events recorded at Halema`uma`u, we typically see an initial high frequency vibration lasting for a few seconds that have been correlated with rockfalls. This is followed by about 30 seconds of a long-period (LP) oscillation with an approximately 2- to 3-second period. The final phase of the signal is several minutes of a very-long-period (VLP) oscillation with an approximately 25- to 30-second period. The LP signals are interpreted to be from the uppermost portion of the conduit and VLP signals are interpreted to be fluid passing through a deep constriction in the conduit through which lava rises to the pond surface we see in the webcam.

DI tilt event: DI is an abbreviation for 'deflation-inflation' and describes a geophysical event of uncertain volcanic significance. DI events are recorded by tiltmeters at Kilauea summit as an abrupt deflation of up to a few microradians in magnitude lasting several hours (weak DI events) to 2-3 days (strong DI events) followed by an abrupt inflation of approximately equal magnitude. The tilt events are usually accompanied by an increase in summit tremor during the deflation phase. A careful analysis of these events suggests that they may be related to changes in magma supply to a storage reservoir at less than 1 km depth, just east of Halema`uma`u crater. Usually, though not always, these changes propagate through the magma conduit from the summit to the east rift eruption site, as many of the DI events at Kilauea summit are also recorded at a tiltmeter at Pu`u `O`o delayed by several hours. DI events often correlate with lava pulses and/or pauses in the eruption at the Pu`u `O`o/Peace Day vents.

glow: light from an unseen source; indirect light.

Halema`uma`u Overlook vent: has been difficult to describe concisely. The vent is actually a pit, or crater, in the floor of the larger Halema`uma`u Crater which is, in turn, in the floor of the larger Kilauea caldera or crater - a crater within a crater within a crater. It is easiest to describe as a pit inset within the floor of a crater within a caldera. The pit is about 160 m (525 ft) in diameter at the Halema`uma`u Crater floor, is about 50 m in diameter at a depth of 200 m (660 ft) below the Halema`uma`u Crater floor. From November, 2009, to now, a lava pond surface has been visible in this pit.

incandescence: the production of visible light from a hot surface. The term also refers to the light emitted from a hot surface. The color of the light is related to surface temperature. Some surfaces can display dull red incandescence at temperatures as low as 430 degrees Centigrade (806 degrees Fahrenheit). By contrast, molten lava displays bright orange to orange-yellow light from surfaces that are hotter than 900 degrees C (1,650 degrees F).

LPs: - Long Period (LP) events refer to earthquakes that have a lower frequency or tone than typical earthquakes and are usually attributed to the resonance of fluid- and gas-filled conduits, cracks and/or chambers. Because of their association with fluids and gases, LP earthquakes in the vicinity of volcanoes can be useful for monitoring purposes. At other volcanoes LP earthquakes are also known as low-frequency earthquakes, tornillos or B-type earthquakes.

mauka, makai: Hawaiian terms for directions relative to the coast - makai or ma kai (toward the coast) and mauka or ma uka (toward the highlands or away from the coast).

microradian: a measure of angle equivalent to 0.000057 degrees.

pali: Hawaiian term for cliff or precipice.

rise/fall events: one of the episodic behaviors exhibited by the summit lava lake starting in 2009. An event starts with a rise in lava level, a decrease in high-frequency summit tremor amplitude, a decrease or total stoppage of spattering, and a small decrease in tilt. After a period of minutes to hours, the lava will abruptly drain back to its previous level amidst resumed vigorous spattering, seismic tremor amplitude will increase for a short time (a seismic tremor burst) before resuming background levels, and summit tilt will return to its previous level. Gas emissions decrease significantly during the high lava stand (the plume gets wispy), and resume during its draining phase. Taken together, the geophysical characteristics suggest that, during the high lava stand, lava is puffed up with gas trapped under the lava lake crust. 

seismic tremor dropout: these behaviors are identical to rise/fall events except that the lava lake level doesn't rise or fall significantly. High-frequency seismic tremor, gas emissions, and spattering decrease abruptly during a dropout. A dropout can end with a burst of seismic tremor and a significant pulse of gas emissions.

tephra: all material deposited by fallout from an eruption-related plume, regardless of size.

tonne (t): metric unit equal to 1,000 kilograms, 2,204.6 lbs, or 0.984 English tons.

More definitions with photos can be found at http://volcanoes.usgs.gov/images/pglossary/index.php.

Additional Information: 
For a definition of volcano alert levels and aviation color codes: http://volcanoes.usgs.gov/activity/alertsystem/index.php

Maps, photos, Webcam views, and other information about Kilauea Volcano are available at http://volcanoes.usgs.gov/hvo/activity/kilaueastatus.php. A daily update summary is available by phone at (808) 967-8862.

A map with details of earthquakes located within the past two weeks can be found at http://hvo.wr.usgs.gov/seismic/volcweb/earthquakes/

HVO Contact Information: askHVO@usgs.gov

The Hawaiian Volcano Observatory is one of five volcano observatories within the U.S. Geological Survey and is responsible for monitoring volcanoes and earthquakes in Hawai`i.