The Volcano Adventure Guide: Excellent information and background for anyone wishing to visit active volcanoes safely and enjoyably. The book presents guidelines to visiting 42 different volcanoes around the world.
North Sister volcano, along with Middle and South Sister part of the Three Sisters Group in central Oregon Cascades. The group forms a prominent landmark in the Central Oregon Cascades.
North Sister is the glacially eroded remnant of a andesitic-dacitic stratovolcano, exposing the volcano's central plug.
Middle Sister volcano, also over 3000 m in elevation, is located only 2 km to the south. It is basaltic-to-rhyolitic in composition and less eroded than North Sister, but there are no known eruptions in the past 10,000 years.
Latest quakes in Greece: Greece has a lot of earthquake activity, but most of them occur around the margin of the Aegean microplate. The Cycladic islands are located in its center and therefore seismically comparably quiet.
Divergent plate boundaries in oceans: Two ocean plates move apart from each other. Hot upwelling mantle material forms magmas that continuously produce new oceanic crust. An ocean widens.
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