Importance of Earth Science
Everything in the world around us is built upon the Earth, grows on the Earth, or depends on the environment of the Earth in some way. Welcome to this world. Much of human history has been influenced directly or indirectly by earth science. Today as much as ever, major opportunities and problems are tied to Earth and to our understanding of it.
In California, from before the Gold Rush days of the 49ers to the most recent earthquakes, the inhabitants have had an intimate relationship with geology, whether they have thought about it or not. Within its boundaries, this state contains examples of virtually everything geological.
The word "volcano" comes from the little island of Vulcano in the Mediterranean Sea off Sicily. Centuries ago, the people living in this area believed that Vulcano was the chimney of the forge of Vulcan -- the blacksmith of the Roman gods. They thought that the hot lava fragments and clouds of dust erupting form Vulcano came from Vulcan's forge as he beat out thunderbolts for Jupiter, king of the gods, and weapons for Mars, the god of war. In Polynesia the people attributed eruptive activity to the beautiful but wrathful Pele, Goddess of Volcanoes, whenever she was angry or spiteful. Today we know that volcanic eruptions are not super-natural but can be studied and interpreted by scientists.
One of the most frightening and destructive phenomena of nature is a severe earthquake and its terrible effects. An earthquake is a sudden movement of the Earth, caused by the abrupt release of strain that has accumulated over a long time. For hundreds of millions of years, the forces of plate tectonics have shaped the Earth as the huge plates that form the Earth's surface slowly move over, under, and past each other. Sometimes the movement is gradual. At other times, the plates are locked together, unable to release the accumulating energy. When the accumulated energy grows strong enough, the plates break free. If the earthquake occurs in a populated area, it may cause many deaths and injuries and extensive property damage.
Today we are challenging the assumption that earthquakes must present an uncontrollable and unpredictable hazard to life and property. Scientists have begun to estimate the locations and likelihoods of future damaging earthquakes. Sites of greatest hazard are being identified, and definite progress is being made in designing structures that will withstand the effects of earthquakes.
Landsliding is a significant hazard along many hillslopes. Many factors contribute to slides, including geology, gravity, weather, groundwater, wave action, and human actions. Typically, a landslide occurs when several of these factors converge.
For example, many slides on Puget Sound occur in a geologic setting that places permeable sands and gravels above impermeable layers of silt and clay, or bedrock. Water seeps downward through the upper materials and accumulates on the top of the underlying units, forming a zone of weakness.
Floods kill people and destroy homes in many parts of the United States every year. Federal agencies estimate that an average of over 125 people die every year in the United States because of flooding, although losses vary widely from year to year. Property damage ranges into the billions each year, and has been rising in recent decades.
Of course the live video
of a family clinging to their car in a swollen river as rescuers winch
down from a helicopter is so compelling that few viewers can change
channels. But flooding is also worth covering because if people are
informed, they can make decisions that will save lives and reduce property
Few subjects in the Earth sciences are as fascinating to the public as dinosaurs. The study of dinosaurs stretches our imaginations, gives us new perspectives on time and space, and invites us to discover worlds very different from our modern Earth.
From a scientific viewpoint, however, the study of dinosaurs is important both for understanding the causes of past major extinctions of land animals and for understanding the changes in biological diversity caused by previous geological and climatic changes of the Earth. These changes are still occurring today. A wealth of new information about dinosaurs has been learned over the past 30 years, and science's old ideas of dinosaurs as slow, clumsy beasts have been totally turned around. We have learned answers to some frequently asked questions about dinosaurs, with current ideas and evidence to correct some long-lived popular misconceptions. Although much has been discovered recently about dinosaurs, there is still a great deal more to learn about our planet and its ancient inhabitants.
Diamond may well be the world's most versatile engineering material as well as its most famous gemstone. The superiority of diamond in so many diverse industrial applications is attributable to a unique combination of properties that cannot be matched by any other material. For example, diamond is the strongest and hardest known material and has the highest thermal conductivity of any material at room temperature. Diamond that does not meet gem-quality standards for color, clarity, size, or shape is used principally as an abrasive, and is termed "industrial diamond." Even though it is more expensive than competing abrasive materials, diamond has proven to be more cost effective in numerous industrial processes because it cuts faster and lasts longer than any rival material. Synthetic industrial diamond is superior to its natural diamond counterpart because it can be produced in unlimited quantities, and, in many cases, its properties can be tailored for specific applications. Consequently, manufactured diamond accounts for more than 90% of the industrial diamond used in the United States.
Glaciers are made up of fallen snow that, over many years, compresses into large, thickened ice masses. Glaciers form when snow remains in one location long enough to transform into ice. What makes glaciers unique is their ability to move. Due to sheer mass, glaciers flow like very slow rivers. Some glaciers are as small as football fields, while others grow to be over a hundred kilometers long.
Presently, glaciers occupy about 10 percent of the world's total land area, with most located in polar regions like Antarctica and Greenland. Glaciers can be thought as remnants from the last Ice Age, when ice covered nearly 32 percent of the land, and 30 percent of the oceans. An Ice Age occurs when cool temperatures endure for extended periods of time, allowing polar ice to advance into lower latitudes. For example, during the last Ice Age, giant glacial ice sheets extended from the poles to cover most of Canada, all of New England, much of the upper Midwest, large areas of Alaska, most of Greenland, Iceland, Svalbard and other arctic islands, Scandinavia, much of Great Britain and Ireland, and the northwestern part of the former Soviet Union.
Gold is a gleaming symbol of California's bounty and wealth. It was the lure, the promise of California for hundreds of thousands of argonauts who overwhelmed California during the Gold Rush. Gold unleashed the forces that rocketed California to immense growth and development. It sparked a swirl of hopes and dreams, myths and legends, contributions and conflicts.
But the legacies of the Gold Rush are complex--sometimes triumphant, sometimes troubled. It what seemed the blink of an eye, California's first people were overrun by a world rush. Miners saw nature as a force to be overcome to get at the golden treasure. Other rushes followed gold: agriculture, oil, real estate, motion pictures, military industry, computers. California became the nation's industrial, agricultural, and population leader. But the bounty and beauty of the region have paid a price for these achievements. The scales have not always been balanced. Immigrants still come, but the gold they seek is mostly metaphorical; not precious metal but opportunity.
Yellowstone National Park is home to some 10,000 thermal features, over 500 hundred of which are geysers. In fact, Yellowstone contains the majority of the worlds geysers. Within Yellowstone's thermal features can be seen the product of millions of years of geology at work. Much of Yellowstone sits inside an ancient volcanic caldera (the exploded crater of a volcano). The last major caldera forming eruption occurred 600,000 years ago. For hundreds of thousands of years following that, subsequent lava flows slowly filled in most of the caldera. Even now, in some places, nearly molten rock resides as little as 2-5 miles below the surface. Heat from the volcanic activity makes its presence known by heating ground water and creating the therma features we now see. The four basic types of thermal features present in the Park are geysers, hot springs, fumaroles, and mudpots. Many of these are concentrated in Yellowstone's major geyser basins: Upper, Midway, Lower, Norris, West Thumb, Shoshone and Heart Lake.
Oil and natural gas touch our lives in countless ways every day. Together, they supply 65 percent of our nation's energy. They fuel our cars, heat our homes and cook our food.
But did you know that oil and natural gas also help generate the electricity that powers our daily lives? Or that crude oil supplies the building blocks for everything from dent-resistant car fenders to soft drink bottles to camping equipment?
Explore this area to learn more about oil and natural gas, how they are produced and how they become the products you count on. You'll also find useful tips on how to conserve energy and use oil and natural gas products in ways that protect you, your family and our environment.
A cave or cavern is any naturally occurring void, recess, or system of interconnecting passages beneath the earth. Caves underlie 20% of the United States. These unique and sensitive environments harbor rare animal life, fragile mineral formations and valuable ground water resources.
Cave formations, such as stalactites and stalagmites, take hundreds to thousands of years to form. These irreplaceable resources provide aesthetic enjoyment for cave visitors. Mineral deposits, such as onyx and amethyst clusters, also give caves their natural beauty.
Clues from past people and past cultures can be found in caves. Artifacts such as arrowheads, pottery, woven slippers and tools help archaeologists answer questions about how past cultures lived. Caves provided shelter and natural resources for prehistoric people. Rock carvings and mudglyphs inside caves also offer us insight into the lives of these people.
Mountains are produced by forces in the earth that cause parts of the earth's crust to rise while others sink. Uplift of the crust, combined with chemical and physical erosion by air, water, and ice over millions of years, produces the spectacular scenery found in mountains.
At the very high temperatures and pressures found miles below the earth's surface, rocks can actually flow when density differences are produced by differential heating and cooling of parts of the mantle and lithosphere. The flowing of rocks in the mantle and lithosphere subjects parts of the crust to tension (pulling apart), while other parts are subjected to compression (squeezing together). Rocks are relatively weak and brittle under tension and, consequently, crust under tension tends to break up into giant blocks. Rocks are stronger under compression but when the compressive forces get very large, rocks deform by flowing, folding, and breaking.