Geology of the Pacific Northwest debris. Rising above this volcanic platform are a few strikingly large volcanoes that dominate the landscape. The Cascade volcanoes define the Pacific Northwest section of the Ring of Fire, an array of volcanoes that rim the Pacific Ocean. The Ring of Fire is also known for its frequent earthquakes. The volcanoes and earthquakes arise from a common source: subduction. Beneath the Cascade Volcanic Arc, a dense oceanic plate plunges beneath the North American Plate; a process known as subduction. As the oceanic slab sinks deep into the Earth's interior beneath the continental plate, high temperatures and pressures allow water molecules
Circum-Baikal Railway in operation: Kultuk, Maritui, Ulanovo, and Baikal, with one section of double track at 137 km. The Circum-Baikal contains thirty-eight tunnels with a total length of 9063 m (the longest of them, a tunnel through cape Polovinnyj, is 777.5 m long). There are also 15 stone galleries with a total length of 295 m and 3 ferro-concrete galleries with apertures, 248 bridges and viaducts, and 268 retaining walls. The Circum-Baikal has no equal in Russia as to the richness of engineering constructions. The tunnels and stone galleries of the Circum-Baikal are unique in that they were constructed atypically and have