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Archive for Volcanoes

Pinacate Peaks Amidst Sand Dunes of the Gran Desierto de Altar, Mexico

31.7N 114.7W

November 30th, 2009 Category: Rivers, Volcanoes

Mexico - November 17th, 2009

Mexico - November 17th, 2009

The Colorado River pours thick tan sediments around Montague Island and into the Sea of Cortes. The sediments gradually take on a greenish appearance as they diffuse southward.

North of the rivermouth is the Gran Desierto de Altar, part of the Sonoran Desert. The desert’s vast sand dune field appears mostly tan here, with the exception of a dark brown circular area in the upper right quadrant.

This part of the desert is the location of the Pinacate Peaks, a group of volcanic peaks and cinder cones. The tallest of the peaks is Cerro del Pinacate (also called Volcan Santa Clara), elevation 3,904 feet (1,190 m).

Mount Nemrut and Arms of Lake Van, Turkey – November 30th, 2009

38.6N 42.9E

November 30th, 2009 Category: Image of the day, Lakes, Volcanoes

Turkey - November 24th, 2009

Turkey - November 24th, 2009

Lake Van is one of the largest endorheic lakes in the world and the largest lake in Turkey, located in the far east of the country in the Van district. It is a saline and soda lake, receiving water from numerous small streams that descend from the surrounding mountains. Here, the Nemrut Volcano can also be seen west of the lake, partially covered with snow.

The lake’s average depth is 171 metres (560 ft) with a maximum recorded depth of 451 metres (1,480 ft). The western portion of the lake is deepest, with a large basin deeper than 400 m (1,300 ft) lying northeast of Tatvan and south of Ahlat. This deeper section of the lake appears navy blue here.

The eastern arms of the lake, on the other hand, are shallower and appear greenish from sediments and algae. The Van-Ahtamar portion, southeast, shelves gradually, with a maximum depth of about 250 m (820 ft) on its northwest side where it joins the rest of the lake. The Erciş arm, northeast, is much shallower, mostly less than 50 m (160 ft), with a maximum depth of about 150 m (490 ft).

Over 100 species of phytoplankton have been recorded in the lake including flagellates, diatoms, bacteria, cyanobacteria, green algae and brown algae. Thirty-six species of zooplankton have also been recorded including Rotatoria, Cladocera and Copepoda in the lake.

Volcanoes Near Lake Taupo, New Zealand

38.7S 175.8E

November 27th, 2009 Category: Lakes, Rivers, Volcanoes

New Zealand - November 13th, 2009

New Zealand - November 13th, 2009

Several volcanoes are visible near Lake Taupo, the large lake at the upper right, in this orthorectified image of New Zealand’s North Island. Following the Tongariro River, one of the lake’s main tributaries, upstream from the lower end of the lake, one comes to a smaller lake known as Lake Rotoaira.

Between these two lakes is Mount Pihanga, a 1325m volcanic peak on the North Island Volcanic Plateau. Another smaller body of water, Lake Rotopounamu, is at the north-west foot of the mountain. Mt. Pihanga and Lake Rotopounamu are part of the 5,129ha Pihanga Scenic Reserve, which in 1975 was added to the Tongariro National Park.

South of Mount Pihanga is Mount Tongariro, a volcanic complex located 20 kilometres to the southwest of Lake Taupo. It is the northernmost of the three active volcanoes that dominate the landscape of the central North Island. This volcanic massif, often simply referred to as Tongariro, has a height of 1,978 metres.

The volcano consists of at least 12 cones; Ngauruhoe, while often regarded as a separate mountain, is geologically a vent of Tongariro. It is also the most active, having erupted more than 70 times since 1839.

Continuing south of Ngauruhoe is Mount Ruapehu, an active stratovolcano at the southern end of the Taupo Volcanic Zone. It is 23 kilometres northeast of Ohakune and 40 kilometres southwest of the southern shore of Lake Taupo, within Tongariro National Park.  Ruapehu is one of the world’s most active volcanoes and the largest active volcano in New Zealand. It is the highest point in the North Island and includes three major peaks: Tahurangi (2,797 m), Te Heuheu (2,755 m) and Paretetaitonga (2,751 m).

Volcanoes on Coastal Plain of El Salvador – November 26th, 2009

13.4N 88.1W

November 26th, 2009 Category: Image of the day, Volcanoes

El Salvador - November 14th, 2009

El Salvador - November 14th, 2009

Many volcanic peaks dot the landscape of central-eastern El Salvador, to the east of the Lempa River and north of Jiquilisco Bay, in this orthorectified image. To the east of these clusters of volcanoes is San Miguel, the fourth most populous city in El Salvador.

San Miguel is also the name of the stratovolcano located about 15km southwest of the city. The volcano, also known as Chaparrastique, is one of the most active volcanoes in the country.

North of the San Miguel volcano is Chinameca (also known as El Pacayal), a stratovolcano that rises over the town of Chinameca. The volcano is topped by a 2 km wide caldera known as Laguna Seca del Pacayal. A satellite cone on the west side, Cerro el Limbo, rises higher than the caldera rim. Fumaroles can be found on the north side, and it has been the site of a geothermal exploration program.

Continuing westward, the large stratovolcano Usulután can be identified as the peak on the coastal plain closest to the bay. The volcano is topped by a 1.3 km wide summit crater which is breached to the east.

West of Usulután is the Taburete stratovolcano. It is topped by a well-preserved, 150-300 m (500–1000 ft) deep summit crater, with the true summit on the south side of the crater rim.

Kamchatka River Running Across Central Valley of Kamchatka Peninsula, Russia

56.0N 160.4E

November 20th, 2009 Category: Rivers, Volcanoes

Kamchatka Peninsula, Russia - October 7th, 2009

Kamchatka Peninsula, Russia - October 7th, 2009

The Kamchatka River runs eastward for 758 kilometers (471 mi) through Kamchatka Krai in the Russian Far East towards the Pacific Ocean.  The river starts northwest of Avacha and flows north down the Central Valley, turning east near Klyuchi to enter the Pacific south of Kamchatsky Point at Ust-Kamchatsk.

In the segment of the river visible in this orthorectified image, it flows through the Central Valley between the Kamchatka or Central Range (above) and the Ushkovsky (formerly known as Plosky) volcanic massif  in the central part the peninsula.