Though less frequent, earthquakes on the East Coast can typically be felt over a much larger area than those with a similar magnitude on the West Coast. The bedrock in California, for example, is fractured, causing seismic waves that travel through it to dissipate faster. In the eastern half of the United States, the bedrock is less fractured and stronger, allowing earthquake energy to travel farther. (via NYTimes)
Fuente: The New York Times
smooth with scratches (by Ale*)
Pothole Dome is a “roche moutonée”, a block of rock over eroded and polished by a glacier in motion over it. Among the various indicators of such motion, one is the very smooth surface of the rock surface, caused by the grinding of very fine (“rock flour”) sedimentary particles. Another is the presence of parallel scratches on the rock surface, caused by bigger sedimentary particles trapped at the bottom of the ice mass in motion. In this image we can see the smooth surface of the granite, which shows crystals of quartz, biotite, potassium feldspar and very big white crystals of sodium plagioclase, and the scratches, which are particularly visible on said plagioclase crystals. An idea of the size of these features is provided by the lens cap edge on the right.
Pothole Dome, Yosemite National Park,
Tuiolumne County, California
Fuente: Flickr / greenriver
California Desert 44 (by Adolfo Isassi)
The “magic” hour for canyons is not the same as the for open landscapes. It is different for every canyon. If I do not have the advantage of scouting the location beforehand, I use satellite imaging to see form above the canyon orientation relative to the traveling sunlight. Copyright: Adolfo Isassi.
Fuente: Flickr / adolfo_isassi
“In 1929 a sizeable section of land in the southern tip of San Pedro, California began to unexplainably slip into the sea. The 600 block of Paseo Del Mar began moving seaward in 1929 and continued to slip until the mid 1930s. Movement was measured as high as 11 inches a day. Due to quick action, all but two of the houses on the seaward side of the street were moved before toppling into the sea. The eastern section of Point Fermin Park was lost and the entire area is very unstable, yet not moving at the present time.” - Urban Exploration Resource
Travertine ridge view (by Ale*)
This hot spring has built over time beautiful travertine ridges in this area of Eastern California. In this case, travertine formed when hot water supersaturated in calcium carbonate reached the surface. Loss of carbon dioxide to the atmosphere causes calcite precipitation and here are the ridges. The area around the ridges looks desolate and stark because of the high temperature of underground water (65°C / 150°F at the spring proper, less than that - of course - where people go to soak in artificial pools built over time). In the background, the verdant Sierra Nevada rises as a steep wall to the west. Bridgeport, Mono County, California
This hot spring has built over time beautiful travertine ridges in this area of Eastern California. In this case, travertine formed when hot water supersaturated in calcium carbonate reached the surface. Loss of carbon dioxide to the atmosphere causes calcite precipitation and here are the ridges. The area around the ridges looks desolate and stark because of the high temperature of underground water (65°C / 150°F at the spring proper, less than that - of course - where people go to soak in artificial pools built over time). In the background, the verdant Sierra Nevada rises as a steep wall to the west.
Bridgeport, Mono County, California
Fuente: Flickr / greenriver
Earthquakes - Shock Waves (by USGS)
Source: http://gallery.usgs.gov/videos/438. This short excerpt is from a USGS/Bay Area Earthquake Alliance produced television program “Shock Waves: 100 Years After the 1906 Earthquake”. This specific segment describes some of the history behind our modern understanding of the earthquake process. The program received numerous industry awards and was nominated for a regional Emmy Award in the Bay area. It aired twice on KPIX CBS5 and its affiliate station around the time of the April 18, 2006, 100 year anniversary of the Great San Francisco Earthquake. The full program is streamed at the link:http://earthquake.usgs.gov/regional/nca/1906/shockwaves/
The Carrizo Plain from the air. Taken with a basic point-and-click camera from the window of a JetBlue flight from Long Beach to Oakland (left side of the plane, if you’re interested).
Oh San Andreas Fault, look how incredibly obvious you are!
(I also got some pics of right-lateral offsets in streams, but they came out a bit grainy because of the zoom.)
September Nature Geoscience cover photo: Stretching of the continental crust can double its surface area, but it is unknown whether similar amounts of extension occur at depth. Seismic results from the central Basin and Range province, western USA, reveal a thick root of lithospheric mantle that has not been extended and indicates that crustal stretching is decoupled from extension at depth. The image shows badlands in Death Valley, California. See “Differential motion between upper crust and lithospheric mantle in the central Basin and Range”, by Schulte-Pelkum et al., p. 619-6326. Photo by Ian Parker.
A 3-D view of the surface rupture of the April 4, 2010, El Mayor–Cucapah Earthquake (red line) reveals a new fault line connecting the Gulf of California with the Elsinore fault, which is likely to become the main fault at the boundary between the Pacific and the North America plates. Credit: Caltech’s Tectonics Observatory. (via Caltech)