Wednesday, January 31, 2007
Free Science Education Resources
The Federal Government has a nice website where teaching resources created or sponsored by dozens of government agencies have been brought together in an organized collection. This website, free.ed.gov, has resources for Art & Music, Health & Phys Ed, History and Social Science, Language Arts, Math, Science, and more. Of particular note for the earth science teacher are activities related to... - Earthquake Hazards
- Plate Tectonics
- Earth From Space
- Earth science visualizations
- Land Use History of North America
- Geologic Time
- Introduction to Rock Collecting
- Paleontology
- Minerals, Crystals and Gems
- Geology of the National Parks
Labels: Teaching-Science
Friday, January 26, 2007
Earthquake Probability Maps
The US Geological Survey has a website where you can create earthquake probability maps for the area surrounding a specific location that you specify. You can also specify the recurrence interval and earthquake magnitude. Shown below is a map that illustrates the probability of an earthquake of 6.01 magnitude or higher occurring during the next 100 years for the area surrounding Wellsboro, Pennsylvania. 
Earthquake probability map produced at the USGS website.Your map can be output in .gif, .pdf, or .ps format and you can get an ASCII file of the raw data. Create an earthquake probability map at the USGS website. Labels: Earthquakes
Wednesday, January 24, 2007
Nonfuel Mineral Production Up by 18% in USA
Publication Cover
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The value of United States nonfuel minerals production increase by 18% between 2005 and 2006. The value of nonfuel minerals produced in 2005 was $54.6 billion compared to a 2006 production total of $64.4 billion. This impressive increase is a result of multiple factors. - Domestic demand for many commodities increased significantly and mines responded with increased production rates. Mine production of copper, gold, construction sand and gravel, lime, salt, and zinc all increased significantly.
- Growth in mineral demand by developing economies in China, India and other countries resulted in an increase in exports.
- The law of supply and demand - increases in demand for commodities usually causes an increase in price.
In addition to production increases, the value of domestically processed nonfuel mineral materials increased by 10% - from $493 billion in 2005 to $542 billion in 2006. Cement, pig iron and steel all had increases in processed production value. USGS has published details on US nonfuel mineral production in their new Mineral Commodity Summaries 2007 report. If you are interested in reading the details, it can be obtained as a single large PDF file or as two-page summaries for individual commodities. Access to the Mineral Commodity Summaries. Labels: Books-Publications, Minerals
Sunday, January 21, 2007
Subsidence: Houston is Sinking
Lots of attention goes to subsidence reports for New Orleans, but Roy Dokka, an engineering geologist at Louisiana University is switching the channel to another city -- Houston. According to Dokka portions of Houston are sinking at a rate of 1/2 inch per year. Combine that with rising sea level and you have a huge problem. This sinking of the city has made flood plain maps out of date and storm surge models inaccurate. Both now understate the actual risk. Some of the sinking is natural subsidence and part is caused by ground water pumping. The subsidence problem was recognized decades ago and in 1975 the State of Texas created the Houston-Galveston Subsidence District to limit the amount of water withdrawn. Unfortunately the subsidence problem continues and Dokka is trying to focus renewed attention upon it. Read the full story about Houston Subsidence at MySanAntonio.com. Labels: Subsidence
Saturday, January 20, 2007
Central United States Earthquake Facts
New Madrid and Wabash Valley Seismic Zones - Image by USGS
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USGS has a new geologic hazards fact sheet titled "Earthquake Hazard in the Heart of the Homeland". This publication gives an overview of earthquake activity in the New Madrid and Wabash Valley seismic zones. These have produced historic earthquake activity that has strongly shaken portions of Missouri, Kentucky, Tennessee, Arkansas, Illinois and Indiana with effects reaching beyond those states. Three of the largest earthquakes in the continental United States occurred in the New Madrid seismic zone in 1811 and 1812. Studies of historic seismic activities in these areas suggest that within the next 50 years an earthquake of 7.5 to 8.0 magnitude has a 7 to 10 percent chance of occurring and an earthquake of 6.0 magnitude or greater has a 25 to 40 percent chance of occurring. Read the Earthquake Hazard in the Heart of the Homeland factsheet at the USGS website. They also have an older .pdf poster titled Earthquakes in the Central United States - 1699 to 2002 which contains a good summary about this issue with interesting historical perspectives on earthquakes that occurred in this area during 1843, 1895, 1968, 1987 and 2002. Labels: Earthquakes
Thursday, January 18, 2007
New Map of Great Salt Lake
Image by USGS
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USGS and the Utah Department of Natural Resources have published two bathymetric maps of Utah's Great Salt Lake. These maps provide new information relevant to the geometry, chemistry, geologic history, and ecology of the lake. They will also be useful in understanding the transport of salt and contaminants within the lake. Over 12 million depth measurements were made in the lake during the summer of 2006 using a fathometer integrated with a global positioning system. The resulting data was then plotted with GIS software, making detailed calculations of area and volume possible. Four publications have been produced: - Bathymetric Map of the North Part of Great Salt Lake, Utah, 2006
- Calculation of Area and Volume for the North Part of Great Salt Lake, Utah.
- Bathymetric Map of the South Part of Great Salt Lake, Utah, 2005.
- Calculation of Area and Volume for the South Part of Great Salt Lake, Utah
View these maps in .pdf format at the USGS New Maps for Great Salt Lake webpage. Labels: Books-Publications, Maps
Tuesday, January 16, 2007
Himalayan Glacier Retreat Blamed on Global Warming
Glaciers of the Himalaya Mountain Range are an enormous reservoir of fresh water and their meltwater is an important resource for much of India, Bangladesh, Pakistan, Nepal, Bhutan, China and Burma. A team of Indian scientists lead by Anil V. Kulkarni of the Indian Space Research Organization, studied surface area coverage for nearly 500 glaciers in the Chenab, Parabati, and Baspa basins using satellite data collected between 1962 and 2001. They documented that most of these glaciers have retreated significantly. In 1962 a total of 2077 square kilometers was covered by glaciers and in 2001 that area was reduced to 1628 square kilometers. This represents a deglaciation of over twenty percent over a forty year period. 
Landsat image showing glaciers of the Himalaya Mountain Range (light blue) and the sediment-choked and braided valley of the Brahmaputra River (purple) of Eastern India. High Resolution Image - 862KBThey also learned the the number of glaciers actually increased in this area. The increase in count was caused by fragmentation. Climate change was blamed for the decrease in sustainability for these Himalayan glaciers. Read their full article: Glacial Retreat in Himalaya Using Indian Remote Sensing Satellite Data. Labels: Glaciers, Global-Warming
Saturday, January 13, 2007
USGS Streamflow Data Summary
Streamflow levels by state (compared to their historic record) for water-year 2006. Image by USGS
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The US Geological Survey operates over 7000 stream gaging stations across the United States. These stations monitor stream stage, discharge and other parameters and report that data instantly to USGS. Many of these stations are published to the web. Near-real time and historic streamflow data can be accessed at the USGS Water website. For the first time, USGS has prepared an annual summary of this data and this year's summary is now on the web. This summary includes a variety of maps, charts and tables that show regional, seasonal and historic patterns of stream flow. The summary report can be accessed at The USGS WaterWatch Website. | Related Articles on Geology.com: |
Labels: Floods-Flooding
Friday, January 12, 2007
Urbanization and Environmental Geology
A few decades ago most geologists were engaged in the exploration and development of mineral resources. However, environmental geology and the application of geology to problems of the urban environment are slowly demanding the services of an increasing number of geologists. The United States Geological Survey has published "Professional Paper 1726 --
Rates, Trends, Causes, and Consequences of Urban Land-Use Change in the United States". This publication is a collection of 20 papers on urban land use change and its environmental consequences. Papers included are: - The Historical Development of the Nation's Urban Areas
- Cultural and Demographic Factors in Urban Decentralization in the United States—A Historical Overview
- Demographic Drivers of Lakeshore Urbanization in the Ozarks
- Economic Aspects of Urban Decentralization in Historical Perspective
- General Trends Regarding Aggregate Materials for Urban Development, With a Suggested Method for the Analysis of Aggregates Distribution
- Wrestling Sprawl to the Ground-Defining and Measuring an Elusive Concept
- Measuring Urban Sprawl and Extent Through Multitemporal Imperviousness Mapping
- An Assessment of Impervious-Surface Measurement Methods
- Comparing Impervious-Cover Densities on the Basis of Land-Use Types Between Sister Cities on the United States/Mexico Border
- The Use of Spatial Analytical Techniques to Identify Potential Brownfields Sites
- Road Densities for Urban Areas in the Conterminous United States
- Quantifying Urban Intensity in Drainage Basins for Assessing Stream Ecological Conditions
- Analyzing Albuquerque's Landscape Evolution in the 20th and 21st Centuries
- Change to Urban, Agricultural, and Forested Land in Central and Southern Maryland From 1850-1990
- Regional Landscape Change in the Northern Colorado Front Range
- A 30-Year Study of Urban Dynamics for the Municipality of Anchorage, Alaska, 1970-2000
- The Effects of Urbanization on Discharge and Suspended-Sediment Concentrations in a Southern California River
- Changes in Anthropogenic Impervious Surfaces, Precipitation, and Daily Streamflow Discharge-A Historical Perspective in a Mid-Atlantic Subwatershed
- Urban Growth and Seagrass Distribution Trends in Tampa Bay, Florida
- An Overview of the Stressors and Ecological Impacts Associated with Regional and Global Patterns of Population, Land-Use, and Land-Cover Change
Download the .pdf document for Rates, Trends, Causes, and Consequences of Urban Land-Use Change in the United States. Labels: Books-Publications, Geography
Monday, January 08, 2007
Who Owns This Meteorite?
Photograph by Detective R. Gelber, Freehold Township Police Department, used with permission.
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Documented cases of meteorites striking people, homes, cars or other human property are very rare. However, on Friday one of these events happened in Freehold Township, New Jersey. A meteorite crashed through the roof of a family home, bounced off a tile bathroom floor and embedded in a wall. The meteorite was about the size of a golf ball and weighed a little less than one pound. Fortunately there were no injuries. Who owns this meteorite? Is the ownership of a meteorite determined by the concept of "finders keepers", by the laws of "land ownership", or does the government own all objects that fall from space? The answer depends upon the country in which the meteorite has fallen. In the United States, ownership of a meteorite goes to the landowner. A person who owns land is entitled to all natural deposits which occur there - including a meteorite. If the meteorite falls on government property then it belongs to the government. So, this Freehold Meteorite belongs to the property owner (the name of the property owner has not yet been released.) In Australia, most states have legislation that makes meteorites the property of the state museum and anyone who finds a meteorite in Australia should deliver it to the state museum who will reimburse the finder for his/her expenses. In Canada, meteorites are property of the landowner. However, a permit must be obtained to export the meteorite and at that time a Canadian institution can have an opportunity to purchase it. In Japan the principle of "finders keepers" applies to meteorites. In Switzerland and Denmark all meteorite finds are state property but the finder will be paid for surrendering them. These different laws can lead to different behaviors by the finders of meteorites. Where the state confiscates ownership, there can be a temptation to misrepresent the location of the find or sell the meteorite illegally. Where land ownership laws apply, meteorites enter the free market and can be legally traded and held by private collectors. More details on meteorite ownership can be read in a document titled Law of Ownership and Control of Meteorites by D.G. Schmitt, McEwen, Schmitt & Co. Barristers and Solicitors. Related items on Geology.com: |
Labels: Meteor-Meteorite
Wednesday, January 03, 2007
Age of the Grand Canyon by NPS
Page from the Winter 2006-2007 Grand Canyon Visitor's Guide.
Click for readable size image.
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The National Park Service has published a short but informative article on the age of the Grand Canyon in the Winter 2006-2007 issue of the Grand Canyon National Park Visitor's Guide. This article includes summary paragraphs on several basic questions... - How old is the Canyon?
- Why did it form where it is?
- Why is it so deep?
- Why is it so wide?
A data box that accompanies the article lists all of the major rock units in the Canyon and gives their age in millions of years before present. The age of the Canyon is explained as follows... The rocks exposed within Grand Canyon range from the fairly young to the fairly old (geologically speaking). Kaibab limestone, the caprock on the rims of the canyon, formed 270 million years ago. The oldest rocks within the Inner Gorge at the bottom of Grand Canyon date to 1.84 billion years ago. For comparison geologists currently set the age of Earth at 4.5 billion years.
While the rocks are ancient, the canyon is young. Geologists generally agree that canyon carving occurred over the last 5–6 million years — a geologic blink of the eye. See a large-size image of the Grand Canyon Article. Read the full Grand Canyon Visitor's Guide - Large file - .pdf document. Labels: Books-Publications, Teaching-Science
Tuesday, January 02, 2007
New Orleans Slipping Into the Gulf Atop of a Fault
Landsat Image of New Orleans - NASA
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A new study presents another dimension of instability to New Orleans and much of southeast Louisiana. Roy Dokka (Louisiana State University), Giovanni Sella (NOAA) and Timothy Dixon (University of Miami) have published "Tectonic control of subsidence and southward displacement of southeast Louisiana with respect to stable North America" in December's Geophysical Research Letters. Based upon GPS data collected between 1995 and 2006 they conclude that the southeastern portion of Louisiana, including New Orleans and the Mississippi Delta, is sliding atop of a large listric normal fault system. This hanging wall portion of the fault is moving south at a rate of about 2 mm/year and subsiding at a rate of about 5.2 mm/year. 
What is a listric fault?
A normal fault with a dip that decreases with depth.
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Add this to other forms of subsidence, rising sea level, and seventeen category three or higher storms tracking within 100 nautical miles of New Orleans since 1852 and you have what is probably the most precarious major city on this planet. The authors of the study urge those in charge of the rebuiding in the region to consider this motion in their planning and structures. An AP article by Cain Burdeau titled Louisiana Slowly Slipping into the Gulf can be read at Yahoo! News. Labels: Subsidence
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