... Science Frontiers ONLINE No. 46: Jul-Aug 1986 Issue Contents Other pages Home Page Science Frontiers Online All Issues This Issue Sourcebook Project Sourcebook Subjects The Moon And Avalanches The moon is blamed for many things from earthquake triggering to human crimes of passion. Until now, no one seems to have studied the lunar effect on avalanche frequency; even though avalanches are obvious trigger-type phenomena. We find the following para-graph in an article on snow avalanches in general: "Another precipitating factor may be the gravitational pull of the moon. In research published last year, Peter Lev of the Utah Highway Department found that based on a statistical study of moon and avalanche cycles in the Wasatch Mountains during the past 20 years, the chance of an avalanche's occurring on a full and new moon was 100 times greater than it is during other days in the lunar cycle." (Anonymous; "Full Moon May Contribute to 'Loose' and 'Slab' Avalanches," San Jose Mercury News, December 3l, 1985. Cr. Bartindale) From Science Frontiers #46, JUL-AUG 1986 . 1986-2000 William R. Corliss ...

... Science Frontiers ONLINE No. 115: Jan-Feb 1998 Issue Contents Other pages Home Page Science Frontiers Online All Issues This Issue Sourcebook Project Sourcebook Subjects The hilina slump a.k .a . "the big crack"Huge chunks of the Hawaiian Islands have been sliding into the Pacific Ocean for hundreds of thousands of years. (SF#101) Geologists classify these slides as either "slumps" or "debris avalanches." Slumps move just a few inches a year but are prone to bigger, jerky adjustments. Debris avalanches are fast cascades of rocks and soil. In Hawaii, both varieties of movement can involve massive blocks of real estate. In the huge Nu'uanu debris slide, stone blocks 6 miles across tumbled 30 miles out to sea. Both slumps and debris slides may create colossal tsunamis. (Tsunamis are miscalled "tidal waves," but they have nothing to do with tides and do not behave like tides or wind-driven waves.) When large pieces of the Hawaiian Islands slip into the ocean, the entire Pacific Rim is smashed by the resulting tsunamis. In New South Wales, Australia, there is geological evidence that part of this coast was scoured by a Hawaiigenerated tsunami 100,000 years ago. The postulated wave started out about 375-meters ( -mile) high in Hawaii. By the time is reached Australia, it was about 40 meters high. (SF#85) Worse waves may be on tap. A 4,760 cubic mile chunk of the Big Island (Hawaii) is breaking away at the rate ...

... sand about and dunes creep along in deserts, but healthy animals easily avoid burial. Of course, there are rare, sudden downpours even on the Gobi. But one would expect this rain to be quickly absorbed by the sand. Intrigued by the evidence of unexpected catastrophism in the Gobi, scientists from the American Museum of Natural History first took a look at Nebraska's strange Sand Hills. These Sand Hills stretch for thousands of square miles, reach heights of 400 feet, and are believed to be of aeolian origin during the Pleistocene. (See ETM7 in Carolina Bays ) Being a modern analog of the ancient Gobi, the Nebraska Sand Hills might provide some insights as to what happened long ago in the Gobi. An important clue occurs during the summer, when heavy thunderstorms sometimes trigger avalanches of wet sand called "debris flows". These sandslides may be 900 feet long, 50 feet wide, and 4 feet deep. Although they have occasionally partly buried ranch buildings, they are too slow and small to endangerlivestock and wild animals. But what if they were much larger and faster? Back on the Gobi, geologists remarked that the rich fossil deposits were found in structureless sandstone; i.e ., there was none of the cross-bedding seen in sandstones elsewhere in the region. Furthermore, fossils were extremely rare in the cross-bedded sandstones, which were built up over long periods of time. It looked as if the structureless, fossiliferous sandstones were sandslides differing from those in Nebraska in their much greater magnitude. But why were the Gobi sandslides so much ...

... Science Frontiers ONLINE No. 139: Jan-Feb 2002 Issue Contents Other pages Home Page Science Frontiers Online All Issues This Issue Sourcebook Project Sourcebook Subjects Rock-fall Air Blasts It is well known that snow avalanches act like pistons and push blasts of air at hurricane speeds ahead of the deluge of snow. An unusual rock fall at Yosemite created a similar air blast with severe consequences. July 10, 1996. Yosemite National Park, California. We reported this remarkable event in SF#111 for its far-flung seismic waves, which jostled seismographs at Berkeley and Reno over 200 kilometers distant. Actually, there were two rock falls 14 seconds apart. The "rocks" fell from a 665-meter cliff at Happy Isles in the eastern part of Yosemite Valley. No pebbles these; with volumes of 23,000 and 38,000 cubic meters. Although the impact area of the rock falls was not particularly large, the falls generated an air blast and an abrasive sandy cloud that devastated a larger area downslope of the impact sites toward the Happy Isles Nature Center. Immediately downslope of the impacts, the air blast had velocities exceeding 110 m/s [about 245 mph] and toppled or snapped about 1000 trees. Even at distances of 0.5 km from impact, wind velociies snapped or toppled large trees, causing one fatality and several serious injuries beyond the Happy Isles Nature Center. A dense sandy cloud trailed the air blast and abraded fallen trunks and trees left standing. (Wieczorek, Gerald F. et al; "Unusual July 10, 1996, ...