Quick Facts: 

Elevation, 2,487m (8,159feet)

Type, Caldera

Last Eruption, around 2290 BC ( + -  300 years)

Location,  Oregon, United States

How to get there, Teleporting is the quickest way, if you do not have accses to a teleporter use a car..  Preferably a white Land Rover with a roof hatch..

Not so Quick Facts…

The history of Mazama streches back to Native Americans.  They belived that the volcano was the inhabitant of their underworld god, Llao.  The native Americans belived that the cause of the volcano destroying it self was the aftermath of the great battle of the two rivals, Llao the god of the underworld and Skell god of the sky.

It’s name comes from a mounten climping/hiking club named “The Mazamas” when they climbed it 1896.  Befor it erupted it was 11,000 feet high. 

It’s birth started about 400,000 years ago in Pleistocene (the epock from 1.8 million to 10,000 years)  mostly from lava tha flowed form zeh ground with some pyroclastic materials. 

http://upload.wikimedia.org/wikipedia/commons/4/48/Crater_Lake_2.jpg

It’s explosive phase was around 5677.  It exploded on the north part of the main summit with rhyodacite rich eruptions(it is an volcanic rock intermediate in composition between dacite and rhyolite) and “puffed” great big amounts of pumice and ash.  It’s pyroclastic flow(The flows are fast-moving currents of hot gas and rock) spread a 2km wide  and 370m thick (that’s 1200 feet) area. 

Mazama’s final act started with a large eruption that sent a mile (1.6 km) wide column of hot tephra 5 to 10 miles (8.0 to 16 km) into the sky at almost twice the speed of sound. The column collapsed in a series of pyroclastic flows that covered much of the area between and downslope of Llao Rock and Redcloud Cliff. This flow, the first of many, was so hot that it solidified as a welded tuff called the Windglass Welded Tuff. Flow after flow followed in rapid succession, stressing the ability of Mazama’s magma chamber to recharge. The mountain started to sag under its own weight. Concentric ring fractures started to form around the volcano, creating convenient conduits for additional volcanic vents.  (copy/paste wikipedia)  This is were it collapsed

Aftermath

The aftermath of its eruptions are hundreds of square kilometers of the surrounding terrain destroyed by material blasted away from it.  From Mazama to Rogue River Valley a pyroclastic flow traveled 64km or 40 miles while another traveled in between Mount Beiley and Mount Thielsen, over Diamond Lake when it finaly stopped in North Úmpqua River.  Ash and tephra traveled with winds northeast where it covered 500,000+ square miles(Washingston, Oregon California, example).

Thanks and I hope you enjoy.  My first article, beware of noob mistakes..

Beautifull video of the crater left by its collapse.