This Page Hyperlinked [click on] Mount Baker Stratovolcano (background)© ™ ®/ Kulshan Stratovolcano© ™ ®, Simon Fraser University (foreground)© ™ ® ~ Image by Stan G. Webb - In Retirement© ™ ®, An Intelligent Grandfather's Guides© ™ ® next, The Man From Minto© ™ ® - A Prospector Who Knows His Rocks And Stuff© ™ ®
Learn more about the Cascadia Volcanic Arc© ™ ® (Part of Pacific Ring of Fire) Cascadia Volcanoes© ™ ® and the currently active Mount Meager Massif© ™ ®, part of the Cascadia Volcanic Arc© ™ ® [ash flow, debris flows, fumaroles and hot springs], just northwest of Pemberton and Whistler, Canada ~ My personal interest in the Mount Meager Massif© is that the last volcanic vent blew north, into the Bridge River Valley [The Bridge River Valley Community Association (BRVCA), [formerly Bridge River Valley Economic Development Society], near my hometown. I am the Man From Minto© ™ ® - A Prospector Who Knows His Rocks And Stuff© ™ ® Mount Meager Massif© lahar was the largest landslide in Canadian history and one of over 20 landslides to have occurred from the Mount Meager massif in the last 10,000 years. This lahar [a large catastrophic debris avalanche] that flowed to the south, into the Lillooet Valley British Columbia, Canada, on August 6 at 3:27 a.m. PDT (UTC-7). More than 45,000,000 m3 (1.6×109 cu ft) of debris slid down Mount Meager, temporarily blocking Meager Creek and destroying local bridges, roads and equipment. The landslide was large enough to send seismic waves more than 2,000 km (1,200 mi) away into the neighbouring U.S. states of Alaska and Washington and beyond. Multiple factors led to the slide: Mount Meager's weak slopes have left it in a constant state of instability. The massif has been a source of large volcanic debris flows for the last thousands of years, many of which have reached several tens of kilometres downstream in the Lillooet River valley, to the south. It is arguably the most unstable mountain massif in Canada and may also be its most active landslide area. On the north side of the large Mt. Meager massif volcano complex lies Downton Lake Hydro Reservoir, impounded by the La Joi Dam, the uppermost of the Bridge River Project dams. The earliest identified Holocene landslide was in 7900 BP (before the present, or read it as the number of years ago). Further landslides occurred in 6250 BP, 5250 BP, 4400 BP, 2600 BP, 2400 BP, 2240. BP BP, 2170 BP, 1920 BP, 1860 BP, 870 BP, 800 BP, 630 BP, 370 BP, 210 BP, 150 BP and in 1931, 1947, 1972, 1975, 1984, 1986 and 1998. These events were attributed to structurally weak volcanic rocks, glacial unloading, recent explosive volcanism and glacial activity. The last volcano on the top of the massif, however, blew to the north 2,460 years ago, sending talus all the way to Alberta. At the Gold Bridge Golf Course, Bridge River Valley, BC you can play the nine hole course on that talus. . Those who dance with earthquakes and volcanoes are considered mad by those who cannot smell the sulphur. . We begin to deal with BIG (MEGA) EARTHQUAKES at Simon Fraser University (foreground) Kulshan Stratovolcano© / Mount Baker Stratovolcano (background)©New Cascadia Dawn© - Cascadia Rising - M9 to M10+, An Intelligent Grandfather's Guide© next, ~ Images by Stan G. Webb - In Retirement©, An Intelligent Grandfather's Guides©


Countdown to Earthquake Drill - International Great ShakeOut Day is on Thursday, October 20, 2022 at 10:20AM, and annually on the 3rd Thursday in October thereafter - -

Sunday, February 7, 2021

Volcanic evolution of the Pacific Northwest: 55 million year history

https://youtu.be/3o3IJlAHhTE   [5:11 minutes]

IRIS Earthquake Science

OSU/IRIS Collaboration--Pacific Northwest Earth-science series. Tectonics of the Pacific Northest yield a varied volcanic history. The Pacific Northwest boasts an active volcanic arc (Cascades Range), a nearby ocean ridge (Pacific Plate-Juan de Fuca Plate spreading ridge), the world’s youngest flood basalt province (Columbia River Basalt), a hot-spot chain of eastward-younging volcanoes (Yellowstone Trend), volcanism related to continental extension, and more. It is a volcanological wonderland. The western margin of North America has long been dominated by subduction and dextral transtension. This animation attempts to simplify a complex tectonic interaction through cross sections. This animation was created to accompany a Plenary talk at the 2017 IAVCEI meeting in Portland, OR. Written and directed by Anita Grunder, Oregon State University Graphics, animation, & narration by Jenda Johnson,Earth Sciences Animated Reviewed by Ray Wells, U.S. Geological Survey


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