The Toroweap Fault underlies the valley, crossing the Colorado River and continuing south up Prospect Canyon. Volcanic activity began along the fault around seven million years ago and over time lava has ejected from more than 60 vents. Vulcan’s Throne, Mount Trumbull and the Uinkaret Mountains were created as a result of this volcanic activity.
Vulcan’s Throne is a late Quaternary cinder cone on the Toroweap (Sevier) Fault, about 1.7 km (one mile) west of Toroweap overlook. The cone sits on the edge of the 1,006 metre (3,300 ft) deep inner gorge.
Webster took this shot at sunset; a summer thundershower, with occasional lightning, was backlit by the setting Sun. Webster used the lightning trigger on his Canon 5D Mk II camera.
‘This image is a high dynamic range shot with the range increased by superimposing three automatic bracketed images, separated by two exposure stops. Only the first image captured any part of the lightning stroke. Camera Model: Canon EOS 5D Mark II; Focal Length: 15mm; Aperture: f/8.0; Exposure Time: 0.250 s (1/4); ISO equiv: 50; Orientation: Normal; Color Space: sRGB; Software: Adobe Photoshop CS5.1 Windows.’
Photographer: Bret Webster; http://