Wow these are pretty. Thanks. Allison
From: Victor Healey <vic.nospam@gmail.com>
To: Geology2 Mailing List <geology2@yahoogroups.com>
Sent: Thursday, December 8, 2011 10:11 AM
Subject: [Geology2] Beautiful Destruction: 11 Gorgeous Geological Maps of Volcanoes | Wired Science | Wired.com
http://www.wired.com/wiredscience/2011/11/geological-maps-of-volcanoes/?pid=2411&viewall=true
To: Geology2 Mailing List <geology2@yahoogroups.com>
Sent: Thursday, December 8, 2011 10:11 AM
Subject: [Geology2] Beautiful Destruction: 11 Gorgeous Geological Maps of Volcanoes | Wired Science | Wired.com
Beautiful Destruction: 11 Gorgeous Geological Maps of Volcanoes
- By Betsy Mason
- November 17, 2011 |
- 6:30 am |
- Categories: Earth Science
It's not always obvious what it is that scientists find beautiful about a graph, microscope slide, soil sample or some other aspect of their work. It just looks like numbers, blobs or dirt to the rest of us. But sometimes a scientific result or product is so visually appealing, anyone would want to hang it on their wall as art.
Geological maps are often in this category. And some of the most beautiful geological maps are of volcanoes. The colors on geological maps represent different rock units of different ages. With an active lifespan of thousands, or even hundreds of thousands of years, volcanoes produce many layers of ash and flows of lava that will end up as different colors on the map. And with the circular shape of many volcanoes and the radiating rock units, the maps can really be striking.
Here we've collected some excellent examples of geological maps of volcanoes from the United States and Japan. You don't have to be a geologist or even a scientist to have trouble picking a favorite.
Special thanks to the Geological Survey of Japan for permission to use some of their maps in this gallery.
Above:
Miyake-jima
Type: stratovolcano
Last eruption: 2010
Summit elevation: 2,674 ft. (815 m.)
Last eruption: 2010
Summit elevation: 2,674 ft. (815 m.)
Miyake-jima rises around 3,600 feet from the sea floor around 110 miles southwest of Tokyo. The top of the volcano is a 5-mile-wide circular island that is home to around 3,000 people. It has erupted as recently as last year, but its last big eruption sequence occurred in June-July and September 2000 (see below). It was accompanied by thousands of earthquakes including a magnitude 6.4 that killed one person, 9-mile high ash plumes, pyroclastic flows, ashfalls, crater collapses and an evacuation order that lasted five years and kept the island largely uninhabited until January 2011.
Geological Map: Geological Survey of Japan. Image below: Miyake-jima in July 2000 (left) after large eruptions and venting steam in September 2000 (right) (Ash appears dark gray, vegetation appears red, and water is blue-gray). NASA.
Aso
Type: caldera
Last eruption: 2011
Summit elevation: 5,223 ft. (1,592 m.)
Webcams: one | two | three | four (multiple views) | five
Last eruption: 2011
Summit elevation: 5,223 ft. (1,592 m.)
Webcams: one | two | three | four (multiple views) | five
Mount Aso is Japan's largest volcano and its 15-mile-wide caldera is among the largest in the world. The caldera was created by four huge eruptions between 300,000 and 90,000 years ago. Today, around 50,000 people live within the caldera walls. There are 17 volcanic cones in the caldera, among them is one of the country's most active modern volcanoes, Naka-dake (see image below) which is a popular tourist site that can be reached by road or cable car.
Aso has erupted 168 times in the last 1,500 or so years, most recently in May and June 2011 when ash plumes rose as high as 8,000 feet. Volcanic gas has sent at least 71 people to the hospital since 1980. In 1997, two tourists died from gas inhalation. In 1979, three people were killed and 11 injured by ejected blocks.
Geological Map: Geological Survey of Japan. Image below: Naka-dake. Igorberger/Wikimedia Commons.
Kilauea
Hawaii's Kailauea volcano has been erupting continuously since 1983, making it one of the most active volcanoes on Earth and the most dangerous in the United States. The volcano is located within Hawaii Volcanoes National Park, which sees more than a million visitors every year.
Geological Map: USGS (download the map and information pamphlet).
Iwate
Iwate volcano's last eruption was a small one in 1919, but more recently it has been the site of numerous earthquakes, which often indicate magma is moving below a volcano. In 1998 and 1999, Iwate experienced hundreds of quakes included a magnitude 6.1. The volcano is located a little more than 12 miles from Morioka, a city of around 300,000 people.
Geological Map: Geological Survey of Japan.
Asama
Mount Asama is the most active volcano on Japan's main island, Honshu. It sits at the junction of two tectonic plate boundaries where one plate is being pushed beneath another plate, creating long lines of volcanoes called volcanic arcs.
Asama has had several explosive plinian eruptions in the past, most recently in 1983 when a three-month-long episode culminated with 15 hours of ash fall and pyroclasitc flows. The eruption killed an estimated 1,400 people and coated agricultural fields with ash and debris, exacerbating an ongoing famine.
The volcano's most recent eruption in February 2009 sent ash up to 2.5 miles high, caused ashfall in Tokyo 90 miles away and threw rocks more than 3,000 feet away. An eruption in 2004 ejected incandescent blocks and started many fires.
Geological Map: Geological Survey of Japan. Image below: Asama in February 2009 (red represents vegetation, grey-beige is bare rock, white is snow or vapor). NASA.
Crater Lake
Oregon's Crater Lake was formed when Mount Mazama collapsed during an explosive eruptive episode around 7,700 years ago. The nearly 2000-foot-deep lake is the deepest in the country and the caldera basin is more than 3,000 feet deep and more than 6 miles wide. In 1902 the area was made into anational park.
The last known eruption at Crater Lake occurred around 4,800 years ago, but scientists have reason to believe it will erupt again in the future.
Geological Map: USGS (download the map and information pamphlet).
Hokkaido Komagatake
Type: andesitic stratovolcano
Last eruption: 2000
Summit elevation: 3,711 ft. (1,131 m.)
Last eruption: 2000
Summit elevation: 3,711 ft. (1,131 m.)
During three months in 2000, Hokkaido-Komagatake volcano erupted four times, putting five cities under alert. It has had three major historical eruptions in 1929, 1856 and 1640. In the 1640 eruption, part of the volcano's summit collapsed, sending a huge avalanche into the sea that caused a tsunami and killed two people.
Geological Map: Geological Survey of Japan. Image below: Hokkaido-Komagatake volcano.Keyaki/Wikimedia Commons.
Lassen
Northern California's Lassen Peak, which formed around 27,000 years ago is the largest of a group of more than 30 lava domes that make up the Lassen volcanic center. Lassen is the southernmost active volcanic center in the Cascade Range, which also includes Mount St. Helens and Mount Rainier.
The last set of eruptions at Lassen occurred between 1914 and 1917 and were among the first eruptions to be extensively photographed (below). The climactic eruption of the series came on May 22, 1915 sending a column of volcanic ash 30,000 feet into the air, caused ashfall 200 miles away in Nevada, and generated lahars and a large pyroclastic flow. Lassen is very likely to erupt again in the future.
Geological Map: USGS (download the map and information pamphlet). Images below: National Park Service.
Nasu
Type: stratovolcanoes
Last eruption: 1963
Summit elevation: 6,283 ft. (1,917 m.)
Last eruption: 1963
Summit elevation: 6,283 ft. (1,917 m.)
Nasu is a collection of six smaller overlapping stratovolcanoes. A small eruption took place in 1963, but the last deadly eruption occurred in 1410 and may have killed as many as 180 people. In recent years, the area has become a tourist destination with lots of hot springs, spas, resorts and a cable car to the summit of the youngest peak.
Geological Map: Geological Survey of Japan.
Medicine Lake
Medicine Lake volcano in northern California has erupted at least seven times in the past 4,000 years, most recently around 950 years ago. It is the largest volcano in the Cascade Range, which also includes the Lassen volcanic field.
On the northeast flank of this shield volcano, Lava Beds National Monument is full of spectacular lava-tube caves, most of which were formed between 30,000 and 40,000 years ago.
Geological Map: USGS (download the map and information pamphlet).
Sakurajima
Type: stratovolcano
Last eruption: 2011 (ongoing)
Summit elevation: 3,665 ft. (1,117 m.)
Webcams: one | two | three (fourth and fifth from bottom) | four
Last eruption: 2011 (ongoing)
Summit elevation: 3,665 ft. (1,117 m.)
Webcams: one | two | three (fourth and fifth from bottom) | four
Sakurajima is one of the most active volcanoes in the world and has been erupting almost continuously since 1955 with thousands of small explosions and hundreds of minor eruptions every year. Last year it set a new record for most eruptions in a year and is on the list of the world's most hazardous Decade Volcanoes. The eruptions are mostly strombolian, which produce cinder and some lava and usually only affect the summit area of the volcano. But the volcano has had several major historical eruptions of the explosive plinian variety.
In 1914 Sakurajima produced the most powerful eruption in Japan since the 19th century. It explosively erupted ash, but also generated huge lava flows that joined the island to the mainland and annexed several smaller nearby islands. The earthquakes preceding the eruption killed 35 people but also prompted most of the inhabitants to evacuate before the eruptions.
Geological Map: Geological Survey of Japan. Image below: Sakurajima erupting on August 19, 2010.NASA.
See Also:
Betsy Mason is the editor of Wired Science.
Follow @betsymason on Twitter.
Follow @betsymason on Twitter.
No comments:
Post a Comment