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Predicting the Extent of Floods in the Southwest
Posted on Friday, September 30, 2005 @ 11:48 am by Dave Schumaker
A research team with the University of Arizona has been playing with a new way to predict the extent of future flash flooding throughout the Southwest. Current maps from FEMA over estimate the extent of areas that are threatened by floods. The new method “combines a new numerical computer model with two additional methods, satellite-image analysis and field observations.”
In addition to providing better hazard information to the public, revising the floodplains maps could have major economic impact in the rapidly growing Southwest. Often, homeowners in areas deemed to be in a floodplain must buy flood insurance in addition to regular homeowner’s insurance.
“I think the important thing is that we have three methods that give darn near the same result, and it’s a way smaller floodplain than the FAN model FEMA has generally used,” said research team leader Jon D. Pelletier, an associate professor of geosciences at The University of Arizona in Tucson. “These three independent methods converge on the same answer. … That was really surprising to us.”
Cheap Method for Seismic Surveys
Posted on Thursday, September 29, 2005 @ 12:45 pm by Dave Schumaker
A simple and potentially economical method of seismic survey was developed by the scientists at the Arkhangelsk Institute of Ecological Problems of the North and the Schmidt Institute of Physics of the Earth (both a part of the Russian Academy of Sciences). This method uses wind and their effect on causing large buildings and skyscrapers to sway, sending small vibrations through the ground.
Winds are rather strong in the surface atmospheric layers. Internal whirlwinds occur, creating wind surges. Wind impulses cause vibrations to the objects protruding from the relief for 10 meters and more, these vibrations, for their part, being transmitted to the earth’s crust.
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Nevertheless, the method also has shortcomings. The wind is blowing at different velocity, therefore, wind vibrations have a non-constant amplitude. This inconvenience can be avoided in two ways. Additional vibration recorders can be installed in the vicinity of the source, and then readings of all devices are to be compared. Changes in vibrational amplitude of each construction can be statistically evaluated and the researchers can further work with one station.
Arctic Climate Changing
Posted on Thursday, September 29, 2005 @ 12:29 pm by Dave Schumaker
Here are two articles on evidence of climate change in the arctic. The first article is from the BBC and reports that the Arctic ice shelf has shrunk in surface area for the fourth consecutive year. The second article is from Reuters and details how the landscape of Alaska has been transformed due to permafrost thawing out.
From the BBC Article:
The new data shows that on 19 September, the area covered by ice fell to 5.35 million sq km (2.01 million sq miles), the lowest recorded since 1978, when satellite records became available; it is now 20% less than the 1978-2000 average.
The current rate of shrinkage they calculate at 8% per decade; at this rate there may be no ice at all during the summer of 2060.
Scientists in the BBC article were quoted as saying that humans are at least partly to blame for the warming.
Lake Nyos Growing Threat
Posted on Tuesday, September 27, 2005 @ 11:15 am by Dave Schumaker
Lake Nyos sits atop a volcano in Cameroon. It is most notable for an event in 1986 where it released large quantities of carbon dioxide that flowed downhill, suffocating upwards of 1,800 people. Afterwards, scientists from around the world came together and created a project to de-gas Lake Nyos. However, it appears the project may not be as effective as thought. Scientists warn that Lake Nyos still contains potentially life threatening quantities of CO2 dissolved within it.
“In both lakes, there’s been a 12% to 14% reduction in overall gas content, which is the good news,” said Kling. “The bad news is that the single pipes are not sufficient to rapidly remove as much as is needed to make them safe. There is still more gas in both lakes than was released in the 1980s.
“We could have a gas burst tomorrow that could be bigger than either of those disasters and every day we wait is just an accumulation of the probability that something bad is going to happen.”
Supernova Responsible for Mammoth Disappearance?
Posted on Sunday, September 25, 2005 @ 12:10 am by Dave Schumaker
A scientist with the Lawrence Berkeley National Laboratory is presenting a new theory on why mammoths may have gone extinct nearly 13,000 years ago. Previous theories on their disappearance have revolved around climate change or human involvement. This new theory proposes that a supernova was responsible for the extinction. Now, a supernova may join the lineup. Firestone and West believe that debris from a supernova explosion coalesced into low-density, comet-like objects that wreaked havoc on the solar system long ago. One such comet may have hit North America 13,000 years ago, unleashing a cataclysmic event that killed off the vast majority of mammoths and many other large North American mammals. They found evidence of this impact layer at several archaeological sites throughout North America where Clovis hunting artifacts and human-butchered mammoths have been unearthed. It has long been established that human activity ceased at these sites about 13,000 years ago, which is roughly the same time that mammoths disappeared.