Sunday, December 13, 2009

Tavurvur's eruption seen from space

Since a major eruption in 1994 that forced the complete evacuation of the nearby city of the same name, Rabaul Volcano on the island of New Britain has remained intermittently active. Rabaul is a large caldera volcano whose eastern rim has been breached and flooded by the sea.

Numerous vents and cones occur around the rim, including Tavurvur Cone, which was erupting when this image was captured by the Advanced Land Imager on NASA’s Earth Observing-1 (EO-1) satellite on November 30, 2009.

Ash Plume from Tavurvur, Papua New Guinea. Credit: NASA

Ash Plume from Tavurvur, Papua New Guinea. Credit: NASA

From November 20–26, strong eruptions from Tavurvur shot ash plumes 1.5 kilometers into the air above the summit and “showered the flanks with lava fragments that were incandescent at night,” according to a report from the Rabaul Volcano Observatory posted on the Smithsonian Global Volcanism Website.

A caldera volcano forms when a massive eruption empties the magma chamber underlying the volcano; the overlying rock and debris sink into the chamber, leaving a crater at the surface. The eruptions that formed Rabaul Caldera took place as recently as 3,500 and 1,400 years ago.

The 1994 eruption that buried Rabaul involved the currently active Tavurvur Cone as well as Vulcan Cone, located across Blanche Bay to the southwest (not pictured) The city of Rabaul is located on the peninsula across the Great Harbor from Tavurvur. More than a foot of ash fell on parts of the city, and combined with rain, it collapsed many of the small city’s buildings and houses. White dots on the peninsula may be buildings or building sites.

Google view of Pompeii

Pompeii, with its ancient mosaics and buildings preserved by the volcanic eruption that buried the town, is one of the world’s most interesting destinations. But now you don’t need to board a plane to visit: It’s on Google Street View.

Google has mainly focused its 360-degree panoramic service on major living-and-breathing cities around the world like New York, San Francisco, or Rome [USA Today]. But this week the service began to feature Pompeii, allowing people anywhere in the world to tour the ancient marvels on site. Italy’s culture ministry says it hopes the move will boost tourism to the site [BBC News].

The eruption of Mount Vesuvius buried Pompeii in 20 feet of ash in 79 A.D., killing everyone there and destroying other nearby towns like Herculaneum. The disaster, however, preserved much of the city until its rediscovery in the 1700s, giving archaeologists a window into 1st-century life in the Roman world.

Pompeii isn’t the only historical site going live on Google Street View. Among the foreign sites appearing Thursday were Stonehenge, Prague, the ancient city of Caceres in Spain and famous windmills in the Dutch village of Kinderdijk-Elshout [ANSA].

Image: ANSA

Do you know volcanoes well?

(Volcano Watch is a weekly article written by scientists at the U.S. Geological Survey’s Hawaiian Volcano Observatory.)

We often hear the term “IQ” (intelligence quotient) — but how would you rate your “VAQ” (volcano awareness quotient)? In other words, how well do you know the volcanoes in your backyard?

Let’s begin with a short quiz. No need to flash back to high school and those feelings of panic—sweaty palms and racing heart rate — that set in when your teacher announced a pop quiz on the homework you forgot to do. This quiz won’t be scored by anyone other than you.

Here are five questions to test your VAQ: How many active volcanoes are in the State of Hawaii? What is the most abundant gas emitted by Kilauea and other Hawaiian volcanoes? What is the longest known Kilauea eruption? During the past 200 years, how many times have Mauna Loa lava flows reached the ocean? How many earthquakes of magnitude 6 or greater have occurred on Hawai`i Island since 1900?

The answers will be revealed later in this article. First, let us tell you about an upcoming and unparalleled opportunity to learn more about Hawaiian volcanoes — and increase your VAQ.

As we usher in the New Year, Mayor Billy Kenoi will issue a Proclamation from the County of Hawaii, designating January 2010 as “Volcano Awareness Month.” Throughout the month, the USGS Hawaiian Volcano Observatory (HVO), in cooperation with Hawaii Volcanoes National Park, Hawaii County Civil Defense, and the University of Hawaii at Hilo, will sponsor various events to promote the importance of understanding and respecting the volcanoes on which we live.

Volcano Awareness Month kicks off 10 a.m. Saturday, Jan. 2 with an opening event on the Jaggar Museum overlook in Hawaii Volcanoes National Park. The public is invited to attend.

Kenoi has been invited to read the Proclamation, and featured speakers will include “Thomas A. Jaggar,” HVO’s founder and first Director (portrayed by Peter Charlot), and Jim Kauahikaua, HVO’s current Scientist-in-Charge. Cindy Orlando, Superintendent of Hawaii Volcanoes National Park, Quince Mento, Administrator of Hawaii County Civil Defense, and other special guests will also address volcano awareness.

This opening is just the first of a month-long series of events focusing on Hawaiian volcanoes. They include guided hikes, evening talks, teacher workshops and other extraordinary programs. In order to reach a wide audience, they are scheduled on weekdays, as well as weekends. Many of the programs and activities will be held in Hawaii Volcanoes National Park, but some will also take place in Hilo and in Kona.

HVO selected January 2010 as Volcano Awareness Month, largely because Jan. 3, 2010, marks the 27th anniversary of Kilauea’s ongoing east rift zone eruption. It will also be 20 years since Kalapana was buried beneath lava and 50 years since Kapoho was inundated by fast-moving lava flows. The destruction of these two communities is a sobering reminder of why it’s important to understand how Hawaii’s volcanoes work.

Now, back to the quiz. The answers, in order of the questions asked, are as follows.

There are six active volcanoes (defined as erupting in the past 10,000 years) in the State of Hawaii. Water vapor is the most abundant gas released by Hawaiian volcanoes, followed by carbon dioxide (CO2) and sulfur dioxide (SO2). The Ailaau eruption, which lasted about 60 years from around 1410 to 1470, is Kilauea’s longest known eruption. Eight Mauna Loa lava flows, from eruptions in 1868, 1887, 1919, 1926, 1950, and 1959, have reached the ocean in the last 200 years. Since 1900, there have been 13 magnitude-6 or greater earthquakes—in 1929, 1941, 1950, 1951, 1952, 1954, 1962, 1973, 1975, 1983, 1989, and 2006.

Even if you aced the quiz—and especially if you did not—we encourage you to participate in Volcano Awareness Month events to learn more about Hawaii’s volcanoes. Don’t be caught with a low “volcano awareness quotient” if the volcano in your backyard erupts!

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