Kilauea 2/22

Activity for 2/21-2/22:

At the summit activity continued at the Halema`uma`u crater. A large gas plume reached 600 meters into the air, and small amounts of ash were carried upwards also. In the crater lava activity continued with lava levels dropping and rising and lava circulating. Some small lava fountaining also occurred. 2 earthquakes occurred the were large enough to be located.

At the Pu`o`O`o crater some glow (of lava) was also visible. Lava flowed from the TEB vents onto the TEB flow field. Some vegetation was burned due to lava flows.

Respond by explaining what lava fountaining is AND copy and paste a link to a picture of lava fountaining into your reply.

Every day all Kilauea update info from http://volcanoes.usgs.gov/kilaueastatus.php

Posted by Emma Heaps

Volcanic Landforms Study Questions

1. A shield volcano forms when quiet eruptions over time produce lava flows that run over land (and can spread out) and cool and harden into volcanic rock. Overtime, these layers of volcanic rock build on-top of each other to make a gently sloping shield volcano. (Example: Kilaeua)

2. Composite volcanoes form when repeated eruptions of pyroclastic flow (cooling volcanic rock particles of ash, cinder, and bombs) build up on each other. These are often steep, cone-shaped mountains. (Example: Paricutin)

3. Eruptions of lava flows (quiet) and pyroclastic flow (explosive) alternate to form composite volcanoes. The volcano is then built up of a layer of ash, cinders, and bombs and then a layer of lava over and over again. The volcanoes have a steeper slope at the top and then a gentler slope at the bottom. (Example: Mt. St. Helens)

4. Often the soils produced from volcanic eruptions and volcanic rock are actually high in nutrients and can be good to grow crops.

5. See above

Posted by Emma Heaps

Kilauea 2/18

Activity for 2/17-2/18:

At the summit:
The lava levels in the pit of Halema`uma`u crater were low, but the lava was still moving around inside the crater. At 7 AM a hybrid earthquake occurred alogn with rockfalls. At this time the lava level lowered more. Seismic tremors continued at steady levels and two earthquakes below Kilauea were large enough to be located.
The tiltmeter recorded DI deflation and a a "positive offset" at 7AM when the hybrid earthquake occurred. The GPS receivers also indicated contraction (they came closer together which confirms that deflation is occurring).

At the east rift zone:
The tiltmeter at Pu`o`O`o crater also recorded DI deflation. Pahoehoe lava flowed down the flow fields.

The Hawaiian volcano Observatory Page updates their info with images of tiltmeter and GPS recordings. Click here to see the recording. Post below by either explaining what the tiltmeter data shows occurred during the past few days in February OR explain what the GPS receiver show has occurred since March 2008.

Posted by Emma Heaps

Kilauea- 2/17

Activity at Kilaeua 2/16-2/17:

At the summit, at Halem`uma`u crater there still lava spattering and movement in the crater. Another DI (deflation-inflation) event started at 9:30 PM yesterday. Episodic tremors were recorded throughout the night, starting at 6PM last night.

Also at the summit, there gas plume reaching 600 meters into the air. The plume is moving northward.

Click here to see a picture of a gas plume at the Haleuma`u crater, at the summit of Kilauea.

Currently, at the summit of Kilauea 900 tonnes per day of sulfur dioxide (SO2) gas is being released into the air. Between the years of 2003 and 2007 the average amount of sulfur dioxide released a day was only 140 tonnes per day.

In order to respond to this post click here and read about volcanic gases. Respond with a post that describes at least one effect of SULFUR DIOXIDE (SO2) GAS.

Posted by Emma Heaps

Volcanic Eruptions Study Questions

1. To see the different parts of a volcano see page 211 in your textbook.

2. High silica content means high viscosity magma. When there is high viscosity magma, it will not flow out of the volcano easily so explosive eruptions will be more likely.

3. A quiet eruption occurs when magma is low in silica content (low viscosity). Lava flows easily out of vents and volcanic gases bubble out of the lava. Pahoehoe and aa lava can be formed by quiet eruptions. Hazards from quiet eruptions are lava flows and fires.

4. Explosive eruptions occur when magma is high in silica content (high viscosity). Lava does not flow easily out of the volcano and gets clogged up in the volcanic vents. When the vents are clogged, pressure from the magma and volcanic gases builds up inside the volcano. When the volcano finally erupts it is an explosive eruption. This type of eruption will cause pyroclastic flow (rock particles of various sizes called ashes, cinders, and bombs). Ash fall, landslides, rock falls, and release of volcanic gases are hazards associated with explosive eruptions.

5. Changes at a volcano can signal to scientists that it may erupt. Scientists often use tools such as tiltmeter or GPS receivers to see if there is any movement or tilt of the ground at a volcano. Tilt and ground movement can indicate that a volcano may erupt soon. Earthquakes occurring at a volcano (often monitored by seismographs) can indicate that a volcano may erupt soon.

Also, volcanic gases escaping signal that a volcano may erupt soon.

Posted by Emma Heaps

Kilauea 2/16

Activity from 2/15-2/16:

At the summit, at Halem`uma`u crater there was even more lava spattering and movement in the crater. Inside the crater, the lava level repeatedly rose as fell, changing it height by as much as 10 meters. This movement occurred from 8 AM to 6 PM, then it rose and fell less, then by 3 AM much rising and falling was occurring again. Another DI (deflation-inflation) event started). At 12:20 PM yesterday deflation occurred, and afterwards at 7:00AM today inflation occurred. When more movement of the lava occurred more seismic tremors were recorded at the crater.

At the TEB vent, lava continued to flow out and feed surface lava flows.

Deflation-Inflation or DI events are know to occur at the summit of Kilauea (at Halema`um`u crater) when the crater is expanding or contracting. Click here to read a "Volcano Watch" article from May 2009 about the significance of DI events at Kilaeua. Respond to this post by commenting with something you have learned about DI events at Kilauea.

Posted by Emma Heaps

Kilauea- 2/11

Activity for 2/9-2/10:

At the summit, at Halema`uma`u crater there was lava spattering in at least two places in the bottom of the crater. Rock falls also occurred in the crater last night. At 1:15 AM the view from the webcam was blocked by fumes and rock dust. At 4:10 AM a rock fall occurred. At 4:15 AM there was finally a clear view form the webcam again and lava has risen above the opening in the crater. Seismic tremors were variable moving between being constant and coming in episodic bursts.

Lava continued to flow out of the TEB vent. Surface lava flows are advancing slowly and both pahoehoe and aa flows have been detected.

Rock falls are not uncommon at Kilauea. Click here to see a video of lava movement within the Halema`uma`u crater and rock falls from September of 2009. Respond below by answering this question: what do you think is causing rock falls at the Halema`uma`u crater?

Everyday Kilauea update info is found at http://volcanoes.usgs.gov/kilaueastatus.php.

Posted by Emma Heaps

Links to Volcanic Eruption Videos

Mt. St Helen's eruption

Krakatoa eruption

Kilaeua ocean entry eruption

Posted by Emma Heaps

Kilauea 2/9

Activity for 2/7-2/8:

At the summit, at Halema`uma`u crater there was lava spattering in at least two places in the bottom of the crater, and the lava level was rising. The amount of sulfur dioxide gas leaving the vent is still elevated compared to the 2003-2007 average amount. GPS receivers recorded expansion at the Halema`uma`u crater. Seismic tremors increased at 9 PM last night and then decreased. There was a normal amount of smaller earthquakes that occurred. There were five earthquakes beneath Kilauea that were able to be located.

At the Pu`u`O`o crater there was an increase in seismic tremors, and the tremor level was constant at the TEB vents. GPS receivers recorded expansion of the rock at the Pu`u`O`o crater.The number of small earthquakes were within normal ranges. Scientists were able to map out a pahoehoe lava flow from the TEB vent, and they discovered that it had moved 700 meters in the last five days.

Kilauea is currently erupting, and is a very active volcano. Click here to read about the activity at nearby volcano Mauna Loa. After you have read about the current activity at Mauna Loa and about the current activity at Kilauea mentioned in this post, respond to this post by comparing and contrasting the current activity at these two volcanoes.

Posted by Emma Heaps

Properties of Magma Study Questions

1. Viscosity is a physical property. Viscosity of a substance can be observed without changing the chemical composition of the substance.

2. As viscosity increases a liquid will flow more slowly. So a high viscosity means a slower flowing liquid. A low viscosity means a faster flowing liquid.

3. Increased friction between particles mean higher viscosity (more resistance to flowing). So increased friction also mean a liquid will flow more slowly.

4. Temperature and silica content effect the viscosity of magma.
Higher temperature means a lower viscosity.
Higher silica content means a higher viscosity. (think "silica is sticky")

Aa is higher viscosity magma, and pahoehoe is lower viscosity magma.

Posted by Emma Heaps

Kilauea 2/8

Activity from 2/6-2/7:

At the summit, at Halema`uma`u crater there was lava spattering in at least two places in the bottom of the crater, and the lava level was rising. Inflation of the summit that had been occurring was decreased. There were seven earthquakes beneath Kilauea that were able to be located.

At the Pu`u`O`o crater there also a decrease in inflation that had been occurring. Seismic activity at both the Pu`u`O`o vent and TEB vent was low.

Seismic activity and earthquakes are important to scientists when they are study volcanoes. You can click here to see a map of recent earthquakes on the island of Hawaii. Then, click here to read about monitoring seismic activity near volcanoes, and use the information from this website to respond to either one of the two prompts below.

1. What happens in a volcano to trigger earthquakes?
2. How do scientist measure seismic activity at volcanoes?

Posted by Emma Heaps

Volcanoes and Plate Tectonics Study Questions

1. Volcanoes typically occur at plate boundaries (although they can also occur at hot spots). The occur at plate boundaries because these are place in the crust where magma can come to the surface.
2. At a divergent plate boundary the plates pull apart. In between the plates magma can come to the surface and create a volcano. Volcanoes can occur at both divergent boundaries on land and divergent boundaries in the ocean floor.
3. At convergent plate boundaries where subduction is occuring volcanoes can exist. As one plate is subducted beneath the other some of the rock will melt into magma and create volcanoes. This can happen where two oceanic plates collide (this creates and island arc) or where one continental and one oceanic plate collide.
4. At hotspot mantle material has melted and risen near the surface where it can easily erupt as magma and form a volcano.
5. EXAMPLES

Convergent- Alaskan volcanoes, Indonesia (island arc), Phillipines

Diveregent- Seafloorspreading/mid-ocean ridges, volcaneos in the Great Rift Valley

Hot spot- Hawiian islands, Yellowstone

Posted by Emma Heaps

Kilauea 2/5

Activity for 2/3-2/4:

At the Summit:
At Halema`uma`u crater lava was visible through 3 openings in the bottom of the crater. The glow from the lava is more intense than it has been recently. Nine earthquakes were able to be located below Kilauea last night. Small background earthquakes also occurred, but only the larger earthquakes are able to be located. Pieces of ash were carried out of the crater by the gases leaving the vent.

TEB Vents: Lava continues to flow out of the TEB vents and down the flow field.

Click here and look at recent pictures of Kilauea. Specifically, be sure to look at the February 3rd pictures of aa lava. Then, search for on the internet or look in a book to read about characteristics of aa lava. Respond to this post by describing some characteristics of aa lava (what is aa lava like?).

Posted by Emma Heaps

Kilauea 2/4

Activity at Kilauea from 2/2-2/3.

Activity a both the summit and at Thanksgiving Eve Breakout vents continued. Lava flowed out to surface flows at the eastern rift zone. Still no lava is flowing through the ocean entry.

At the summit the GPS system detected and elevated number of seismic tremors. Many earthquakes occurred that were so small that their exact location could not be determined. There were 5 earthquakes that were large enough to be located below Kilauea.

Earthquakes often occur where there is eruption and movement at volcanoes. Click here to read more about volcanic earthquakes. After reading the linked page, comment by answering this question:
Why do you think that people live near to Kilauea if earthquakes are signaling an eruption? Think about how lava flows and the activity at Kilauea. There is no right or wrong answer, just be sure to explain yourself.

Posted by Emma Heaps

Kilauea 2/3

Activity for 2/1- 2/2 at Hawaiian volcano Kilauea.

Activity was occuring at two of Kilauea's vents; the summit vent and the TEB, or Thanksgiving Eve breakout vent.

At the summit, the summit vent is emmiting a sulfur dioxide containing gas plume. Also, at the Halema`um`ua crater the lava was seen falling and rising.

At the Pu'u'O'o crater gases (including sulfur dioxide) are also released. The magma is then traveling to the TEB vent and erupting.

Kilauea is a shield volcano, and the fact that it is a shield volcano explains the pattern of lava flows and eruption that we see there. Click here to learn more about shield volcanoes. Read carefully through this website, then below post a response that tells me something you have learned about shield volcanoes from reading the site.

Posted by Emma Heaps