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Vibrations make large landslides flow like fluid

By Guest PostMay 29, 2016Environment, Scienceacoustic fluidization, geoscientists, large landslides, mesa county, vibrations

New research shows why some large landslides travel greater distances across flat land than scientists would generally expect, sometimes putting towns and populations far from mountainsides at risk.

PROVIDENCE, R.I. and WEST LAFAYETTE, Ind. — A new study may finally explain why some landslides travel much greater distances than scientists would normally expect. A team of researchers used a sophisticated computer model to show that vibrations generated by large slides can cause tons of rock to flow like a fluid, enabling the rocks to rumble across vast distances. (more…)

The Making of Antarctica’s Hidden Fjords

By Guest PostMarch 8, 2013Environmentantarctic ice sheet, Antarctica, antarctica topography, columbia university, cooling age, east antarctica, erosion rate, fjords, geologists, george e gehrels, geoscientist, geoscientists, glaciers, global climate, hidden fjords, ice sheet growth, lambert glacier, marine technician, mountains, national science foundation, ocean drilling program, pattern, peter w reiners, prydz bay, rock, rocks, sample, sea level change, sea-level rise, sediments, sidney r hemming, stuart n thomson, ty cobb, university of arizona

Antarctica’s topography began changing from flat to fjord-filled starting about 34 million years ago, according to a new report from a University of Arizona-led team of geoscientists.

Knowing when Antarctica’s topography started shifting from a flat landscape to one with glaciers, fjords and mountains is important for modeling how the Antarctic ice sheet affects global climate and sea-level rise. (more…)

UA Scientists Find Evidence of Roman Period Megadrought

By Guest PostNovember 6, 2011Environment, Scienceannual growth rings of trees, bristlecone pine tree, chronology, climate, cody routson, colorado river, connie woodhouse, core, dendrochronology, extreme drought conditions, geoscientists, jonathan overpeck, la niña, medieval period, multi decade drought period, primary drainage, rio grande, rocky landscapes of alpine or near alpine mountain slopes, san juan bristlecone pines, san juan drainage, san juan rivers, second century a d, shelley littin, south central colorado, southern san juan mountains, southwestern aridity, southwestern u.s, tree bark, tropical pacific ocean, university of arizona

*A new study at the UA’s Laboratory of Tree-Ring Research has revealed a previously unknown multi-decade drought period in the second century A.D. The findings give evidence that extended periods of aridity have occurred at intervals throughout our past.*

Almost nine hundred years ago, in the mid-12^th century, the southwestern U.S. was in the middle of a multi-decade megadrought. It was the most recent extended period of severe drought known for this region. But it was not the first.

The second century A.D. saw an extended dry period of more than 100 years characterized by a multi-decade drought lasting nearly 50 years, says a new study from scientists at the University of Arizona. (more…)

Something Odd Is Happening With Namibia’s Weather

By Guest PostSeptember 16, 2011Environmentburlington, geoscientists, historic record, kuiseb, kyle nichols, mega floods, mineral quartz, namibia, national science foundation, nsf, omaruru, paul bierman, paul cutler, river sediment, riverbeds of western namibia, sediment, skidmore college, sparsely populated african country, swakop, university of vermont, weather in namibia, western namibia

*Southwestern African country is no arid desert–this year*

Something’s up with the weather in Namibia, say geoscientists Kyle Nichols of Skidmore College in Saratoga Springs, N.Y., and Paul Bierman of the University of Vermont in Burlington, Vt.

Nichols and Bierman should know. They’re just back from the western mountains and coastal plain of this sparsely populated African country.

Usually, western Namibia is a dusty place where the stream beds are sand and the “lakes” are nothing more than flats of dried mud.

Not now. (more…)

Stiff Sediments Made 2004 Sumatra Earthquake Deadliest in History

By Guest PostJune 24, 2011Environmentaccretionary prism, aftershocks, coast of sumatra, column of seawater, deadliest tsunami in recorded history, density zone, earthquake, ganges, geologic fault, geological formation, geoscientists, indian ocean, indo australian plate, indonesia, marginal plateaus, nicobar fan, seabed topography, seafloor, sean gulick, sediments, seismic instruments, sound waves, subduction zone, subsurface structures, sumatra, sunda plate, sunda trench, the agency for the assessment and application of technology, the indonesia institute for sciences, the university of southampton, the university of texas at austin, tsunami waves, undersea earthquake, united kingdom

AUSTIN, Texas — An international team of geoscientists has discovered an unusual geological formation that helps explain how an undersea earthquake off the coast of Sumatra in December 2004 spawned the deadliest tsunami in recorded history.

Instead of the usual weak, loose sediments typically found above the type of geologic fault that caused the earthquake, the team found a thick plateau of hard, compacted sediments. Once the fault snapped, the rupture was able to spread from tens of kilometers below the seafloor to just a few kilometers below the seafloor, much farther than weak sediments would have permitted. The extra distance allowed it to move a larger column of seawater above it, unleashing much larger tsunami waves. (more…)

Tag Archives: geoscientists

Vibrations make large landslides flow like fluid

The Making of Antarctica’s Hidden Fjords

UA Scientists Find Evidence of Roman Period Megadrought

Something Odd Is Happening With Namibia’s Weather

Stiff Sediments Made 2004 Sumatra Earthquake Deadliest in History