Swarm of deep earthquakes recorded at Kilauea volcano, Hawaii

Swarm of deep earthquakes recorded at Kilauea volcano, Hawaii

Posted by Adonai on February 27, 2014 in categories Featured stories, Volcanoes





A swarm of very deep earthquakes was recorded in last 24 hours in the area of Punalu`u on the south-west flank of Kilauea volcano, Hawaii.
The following map shows earthquakes registered in last 7 days (February 20 - 27, 2014). Orange markers show current swarm of deep earthquakes. Group of blue markers represent shallow earthquakes registered at the crater.

During February 19 - 25 HVO reported that the circulating lava lake occasionally rose and fell in the deep pit within Kilauea's Halema'uma'u Crater. The plume from the vent continued to deposit variable amounts of ash, spatter, and Pele's hair onto nearby areas. At Pu'u 'O'o Crater, glow emanated from spatter cones on the N and S portions of the crater floor, and a lava pond was active in the NE spatter cone.
Image below, captured February 20, shows the flow front of the Kahaualeʻa 2 flow, looking west. The flow front has focused into a new lobe that is slowly migrating through thick forest, triggering scattered forest fires. The smoke from these fires seems to be "seeding" the cloud above it. The active flow front was 7.4 km (4.6 miles) northeast of the vent on Puʻu ʻŌʻō. Mauna Loa can be seen in the distance. 

HVO's latest update, issued 17:35 UTC on February 26, said the eruption continued at the summit within the east rift zone. The summit tiltmeter network recorded slowing DI deflationary tilt and the summit lava-lake level dropped several meters overnight. At the middle east rift zone, the Pu`u `O`o tiltmeter recorded weak deflationary tilt; the vent continued feeding the Kahauale`a 2 lava flow whose distal end remained active and burning forest to the northeast. Gas emissions remained elevated.

Recent Observations at the middle east rift zone vents: The tiltmeter at Pu`u `O`o cone recorded continuing weak deflationary tilt with several hours of rain-induced increase between 3-7 pm yesterday. The most recent sulfur-dioxide emission-rate measurement was 300 tonnes per day on January 29, 2014, from all east rift zone sources; emission rates typically ranged between 150 and 450 t/d since July 2012. GPS receivers on the north rim and south flank of Pu`u `O`o cone recorded fluctuations mimicking the tilt changes while also recording almost 3 cm of extension since mid-December 2013. The Pu`u `O`o eruption continued with no significant changes. Spatter cones on the floor of Pu`u `O`o crater displayed persistent glow with a possibly crusted-over lava pond within the collapsed northeast spatter cone (see images and video). The south spatter cone continued to erupt lava across the crater floor until about 10 am yesterday morning.

Recent Observations of the Kahauale`a 2 flow: The northeast spatter cone complex continued to feed the Kahauale`a 2 lava flow and PNcam views early this morning clearly showed multiple active breakouts and fires within the adjoining forested areas near its distal tip. The new breakout, reported yesterday high on the tube, was no longer active last night. Early this year, the Kahauale`a 2 lava flow reached 7.8 km (4.8 mi) northeast of Pu`u `O`o by mid-January before stalling. Recent surface flows have been active as small scattered breakouts behind the flow front. HVO geologists on an overflight Thursday mapped the flow front which showed little expansion over the past two weeks, with most active breakouts back from the flow front and margins. On February 20, the active breakouts extended 7.4 km (4.6 mi) northeast of the vent on Pu`u `O`o mostly covering previously-erupted lava flows. 

In general, this slow-moving lava flow has made erratic progress over the past few months. Disruption of the flow front has occurred during strong DI deflation events when the lava supply abruptly decreased causing the flow front to stagnate. DI inflation and resumption of lava supply usually follow a few days later. Breakouts reappear well behind the stalled flow front and take some time to reach the front again. In this way, the flow front has not advanced more than 500 m (1,600 ft) since the first time it stalled in early November, 2013. 

Background: The eruption in Kilauea's middle east rift zone started with a fissure eruption on January 3, 1983, and continued with few interruptions at Pu`u `O`o Cone, or temporarily from vents within a few kilometers to the east or west. A fissure eruption on the upper east flank of Pu`u `O`o 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 Hawai`i 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 Kahauale`a flow, which started from the spatter cone/lava lake at the northeast edge of the Pu`u `O`o crater floor in mid-January, 2013, was dead by late April, but a new flow (informally called Kahauale`a 2) became active in the same general area in early May. In general, activity waxes with inflation and wanes with deflation. (HVO)

Map below shows the Kahaualeʻa 2 flow in relation to the eastern part of the Big Island as of February 20, 2014. The front of the Kahaualeʻa 2 flow was 7.8 km (4.8 miles) northeast of Puʻu ʻŌʻō about one month ago. These forked fingers stalled during a prolonged deflation–inflation cycle (DI event) at Kīlauea’s summit around January 23. Lava flows have since resumed and are approaching the stalled flow front with a new narrow lobe (red), with the farthest active flow on February 20 at about 7.4 km (4.6 miles) from the vent. The area of the Kahaualeʻa 2 flow as of February 7 is shown in pink, while small areas of flow widening as of February 20 are shown in red. Older lava flows are distinguished by color: episodes 1–48b flows (1983–1986) are shown in gray; episodes 48c–49 flows (1986–1992) are pale yellow; episodes 50–55 flows (1992–2007) are tan; episodes 58–60 flows (2007–2011) are pale orange, and episode 61 flows (2011–2013) are reddish orange. The active lava tube is shown with a yellow line.



The following image was acquired by the Earth Observing 1 satellite's Advanced Land Imager sensor on February 2, and shows Kīlauea's summit and east rift zone. Although this is a false-color image, the color map has been chosen to mimic what the human eye would expect to see. Active lava is shown by the bright red pixels, present at the summit - in the lava lake at Halemaʻumaʻu Crater - as well as on the east rift zone on the far end of the Kahaualeʻa 2 flow. These active flows are slowly advancing into the forest, and extend to about 6.7 km (4.2 miles) northeast of the vent on Puʻu ʻŌʻō cone. 

Kilauea, one of five coalescing volcanoes that comprise the island of Hawaii, is one of the world's most active volcanoes. Eruptions at Kilauea originate primarily from the summit caldera or along one of the lengthy E and SW rift zones that extend from the caldera to the sea. About 90% of the surface of Kilauea is formed of lava flows less than about 1,100 years old; 70% of the volcano's surface is younger than 600 years. A long-term eruption from the East rift zone that began in 1983 has produced lava flows covering more than 100 sq km, destroying nearly 200 houses and adding new coastline to the island (GVP).

• Kilauea's photos & videos (HVO)
  
• Maps of Kīlauea’s ERZ flow field (HVO)
  
• Recent earthquakes in Kilauea (MAP/LIST - HVO)
  
• WEBCAMS (HVO)
  

Featured image: Northeast spatter cone in Puʻu ʻŌʻō on February 10, 2014. Image credit: HVO

Thanks to: http://thewatchers.adorraeli.com