Monday 27 February 2012

Snow and Volcanoes on Kamchatka


(Click on image for larger view.)

Besides bordering the Pacific Ocean, the east coast of Eurasia and the west coast of the Americas have something in common. They are part of the Pacific Ring of Fire. Plate tectonic theory explains this fiery ring. As the massive Pacific Plate slides slowly below neighboring plates, rock layers sink into our planet’s super-hot interior. As those rock layers melt, magma travels upward, fueling volcanoes. Consequences of this process are especially evident on the Kamchatka Peninsula, in the far eastern Russian Federation.

The Kamchatka Peninsula sports nearly 70 active volcanoes, although most of them appear calm in this scene from late December 2011. The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite captured this natural-color image on December 19, 2011. Snow blankets the peninsula, but the relatively dark area stretching down Kamchatka likely results from that area’s lower elevation and resulting lighter snow cover.

Acquired two days shy of the Northern Hemisphere’s winter solstice, this scene shows low-angled sunlight, and the Sun’s low angle causes several of the volcanoes to cast long shadows to the north. Many of the volcanoes on Kamchatka are stratovolcanoes—tall, steep-sloped, conical volcanoes. Klyuchevskaya (also Kliuchevskoi) is the tallest, rising to a height of 4,835 meters (15,863 feet). Klyuchevskaya is generally regarded as Kamchatka’s most active volcano, but Bezymianny, Kizimen, Karymsky, and Shiveluch all remain active. In this image, Shiveluch emits a discernible plume that blows toward the south-southwest.

The same volcanic processes that produce ash plumes and lava flows today have shaped the peninsula over the last 3 million years. About 2.5 million years ago, what would become Kamchatka was a magma lake underneath the Pacific sea floor. Once it erupted, the magma began a slow process of volcano construction, eventually building up volcanic plates big enough to add to the Eurasian landmass.

References

Global Volcanism Program. Bezymianny, Karymsky, Kizimen, Shiveluch, Kliuchevskoi, and Shiveluch. Smithsonian Institution. Accessed February 23, 2012.
Kamchatka: Siberia’s Forbidden Wilderness. The Ring of Fire. PBS. Accessed February 23, 2012.
NASA image courtesy Jeff Schmaltz, LANCE/EOSDIS MODIS Rapid Response Team at NASA GSFC. Caption by Michon Scott.

Instrument:
Aqua - MODIS - NASA

No comments:

Post a Comment