Descriptive Structural Geology Of Faults 8 faults and faulting in van der Pluijm Marshak, 1997, Earth Structure An introduction to structural geology and tectonics. http://maps.unomaha.edu/Maher/GEOL3300/week2/fault.html
Extractions: Description of faults Readings: This figure is from a core drilled into basement rocks of South Carolina and shows a pseudotachylite injection vein (red arrow), a pseudotachylite slip surface with secondary associated, high angle oblique microfaults (violet arrow), and a chloritized fault breccia (yellow arrow). The slip here is parallel to the gneissic layering. Notebook terms for week 2 Fault geometry: idealized as a plane with a vector of slip in it and offset and truncated layers. strike and dip of fault plane.
Plate Tectonics Lecture: Transcurrent, Transform Boundaries. The faults are oblique slip; ie they have both dip and strikeslip movement of right slip in California along northwest-oriented faults, geology, vol. http://maps.unomaha.edu/Maher/plate/week9/transcurrent.html
Extractions: Plate boundaries with major strike-slip components. Some terminology: Examples of plate boundaries with major strike-slip components or of major continental transcurrent faults. San Andreas fault system Alpine fault, New Zealand. Dead Sea Transform Red River fault, S central China. De Geer fault zone, Svalbard and NE Greenland. Anatalya complex, Turkey. Nares Strait (?), between Greenland and Canadian Arctic. Great Glen fault, Scotland.
Geologic Fault - Wikipedia, The Free Encyclopedia Such faults are common in the folded Appalachians. In geology, faults are discontinuities (cracks) in the Earth s crust that are the result of differential http://en.wikipedia.org/wiki/Geologic_fault
Extractions: Old fault exposed by roadcut near Harrisburg, Pennsylvania . Such faults are common in the folded Appalachians In geology faults are discontinuities (cracks) in the Earth's crust that are the result of differential motion within the crust. Faults are the source of many earthquakes that are caused by slippage vertically or laterally along the fault. The largest examples are at tectonic plate boundaries, but many small faults are known to exist that are far from active plate boundaries. The two sides of a fault are called the hanging wall and footwall . By definition, the fault always dips away from the footwall. Faults can be categorized into three groups: normal faults, transform (or strike-slip) faults and reverse (or thrust) faults . For all naming distinctions, it is the orientation of the original dip and movement of the fault as it was active which must be considered, and not the present day orientation, which may have been altered by local or regional folding or tilting.
Geology - Wikipedia, The Free Encyclopedia The most significant advance in 20th century geology has been the faults are younger than the rocks they cut; accordingly, if a fault is found that http://en.wikipedia.org/wiki/Geology
Extractions: Geology (from Greek ge- , "the earth") and Î»Î¿Î³Î¿Ï ( logos , "word", "reason")) is the science and study of the Earth , its composition, structure, physical properties, history, and the processes that shape it. It is one of the Earth sciences Geologists have helped establish the age of the Earth at about 4.5 billion (4.5x10 ) years, and have determined that the Earth's lithosphere , which includes the crust , is fragmented into tectonic plates that move over a rheic upper mantle asthenosphere ) via processes that are collectively referred to as plate tectonics . Geologists help locate and manage the earth's natural resources , such as petroleum and coal , as well as metals such as iron copper , and uranium . Additional economic interests include minerals such as asbestos perlite mica phosphates ... quartz , and silica , as well as elements such as sulfur chlorine , and helium Astrogeology refers to the application of geologic principles to other bodies of the solar system. However, specialised terms such as selenology (studies of the Moon areology (of Mars ), etc., are also in use.
Faults Movement along dipslip faults is vertical; one side moves up and the Return to Physical geology Online page Return to Physical geology GSAMS page http://gpc.edu/~pgore/geology/geo101/faults.htm
Relative Dating Lab Examples of faults to illustrate crosscutting relationships. You should remember from Physical geology that a xenolith (which literally means foreign http://gpc.edu/~pgore/geology/historical_lab/relativedating.htm
Extractions: Laboratory Pamela J. W. Gore Department of Geology, Georgia Perimeter College Clarkston, GA 30021 This exercise introduces the concept of relative dating of geologic sequences. Basically, relative dating means determining which rock units are older and which are younger in some particular geologic setting. Stratification or bedding is the most obvious large scale feature of sedimentary rocks. Bedding is readily seen in a view of the Grand Canyon, or almost any other sequence of sedimentary rocks. Each of the beds or strata singular stratum ) is the result of a natural event in geologic history, such as a flood or storm. As time passes many such events occur and the sediment piles up, layer upon layer. In this way, thick sedimentary sequences are formed. STENO'S LAWS the older beds are on the bottom, and the younger beds are on the top . This has come to be called the Principle of Superposition . You can visualize how this occurs if you imagine a stack of newspapers in the corner of a room. Every day you put another newspaper on the pile. After several weeks have passed, you have a considerable stack of newspapers, and the oldest ones will be on the bottom of the pile and the most recent ones will be on the top. This fairly obvious, but very important fact about layering was first noted by Nicholaus Steno, and is the first of three principles which have come to be known as Steno's Laws C B A Vertical geologic section.
What Is A Geologic Map? Part 2 faults can cut through a single geologic unit. These faults are shown with the In addition to being moved by faults, geologic units can also be bent and http://www2.nature.nps.gov/geology/usgsnps/gmap/gmap2.html
Extractions: Letter Symbols In addition to color, each geologic unit is assigned a set of letters to symbolize it on the map. Usually the symbol is the combination of an initial capital letter followed by one or more small letters. The capital letter represents the age of the geologic unit . Geologists have divided the history of the Earth into Eons (the largest division), Eras, Periods, and Epochs , mostly based on the fossils found in rocks. The most common division of time used in letter symbols on geologic maps is the Period. Rocks of the four most recent Periods are found in the San Francisco Bay area shown on this map, so most letter symbols begin with a capital letter representing one of the four Periods: J ( Jurassic - 195 to 141 million years ago), K ( Cretaceous - 141 to 65 million years ago), T ( Tertiary - 65 to 2 million years ago), or Q ( Quaternary - 2 million years ago until today). Occasionally the age of a rock unit will span more than one period, if the period of many years required to create a body of rock happens to fall on both sides of a time boundary. In that case both capital letters are used. For example, QT would indicate that the rock unit began to form in Tertiary time and was completed in Quaternary time. The few geologic units formed an unknown amount of time ago have letter symbols with no capital letters. The small letters indicate either the name of the unit, if it has one, or the type of rock, if the unit has no name. So Kjm (see 1 on map above) would be the symbol for the Joaquin Miller sandstone (formed in the Cretaceous Period), while Ks (location 2) would be the symbol for an unnamed unit of shale formed in the same Period, and gb (location 3) would be the symbol for gabbro (a dark-colored
Visual Glossary Of Geologic Terms faults and earthquakes. spacer image Like most stories in geology, this one starts beneath the surface. As you may know, the continents we live on are parts http://www2.nature.nps.gov/geology/usgsnps/deform/gfaults.html
Extractions: The sudden movement generates an earthquake at a point called the focus . The energy from the earthquake spreads out as seismic waves in all directions. The epicenter of the earthquake is the location where seismic waves reach the surface directly above the focus. A normal fault. Click on diagram to see labels. We classify faults by how the two rocky blocks on either side of a fault move relative to each other. The one you see here is a normal fault . A normal fault drops rock on one side of the fault down foot wall resting or hanging hanging wall
Drilling Into Faults Geologists are getting near the places where earthquakes actually happen. SAFOD is aimed at a part of the San Andreas fault zone where the geology seems http://geology.about.com/od/earthquakes/a/aa_faultdrill.htm
Extractions: var zLb=1; zJs=10 zJs=11 zJs=12 zJs=13 zc(5,'jsc',zJs,9999999,'') About Homework Help Geology Earthquakes Drilling into Faults Homework Help Geology Essentials Geology in a Nutshell ... Help zau(256,140,140,'el','http://z.about.com/0/ip/417/C.htm','');w(xb+xb+' ');zau(256,140,140,'von','http://z.about.com/0/ip/496/7.htm','');w(xb+xb); Sign Up Now for the Geology newsletter! Related reading About faults About subduction About EarthScope More on SAFOD SAFOD's objectives Parkfield geologic map High-T electronic sensors More on IODP IODP: "Understanding Our Planet" (PDF) IODP site Most Popular Rock Picture Gallery Global Seismic Hazard Map Index Landform Picture Gallery Pictures of Geologic Features and Processes ... Mineral Picture Gallery What's Hot Mohs Hardness of Coins Volcanism in a Nutshell Geology Wallpaper Images - Rock Closeups Plate Tectonics - The World's Crustal Plates ... Oldoinyo Lengai Related Topics Geography Environmental Issues Chemistry Archaeology ... Biology From Andrew Alden
Structural.geology.html STRUCTURAL geology. Structural geology. What is Structural geology faults must be able to prove displacement for a fracture to be a fault http://geoweb.tamu.edu/courses/geol101/grossman/Structural.geology.html
Structural Geology Folds and faults ** (10) Lecture text describing the basics. geology 1010 ** (11) Classnotes defining basic terms. Geological Structures ** (12) http://www.geologyshop.co.uk/struct~1.htm
Extractions: Structural Geology Some of the more informative sites on the www for structural geology inclusive; Faults, Folds, Thrusts, Tectonics, Crustal Deformation; also see Plate Tectonics From GeologyShop One of the main sites for geological information worldwide . This is one of over 50 link pages plus there are many original articles. Try our site specific SEARCH ENGINE to find the information you want or go to our MAIN INDEX page. Or try our site specific ORIGINAL articles, FREE geological stuff, or use our HOMEWORK AND TUTORIAL GUIDE POPULAR PAGES: Chalk facts Channel Tunnel facts Channel Tunnel geology Dinosaurs, top 20 sites Dictionaries Dinosaurs, early finds Dinosaur pictures Dinosaurs, facts Earthquakes, top 20 sites Education Fossils, top 20 sites Fossils by group Free stuff Gems Geology jobs Geology of Kent Geotechnical engineering Hominids (early man) Ice ages Igneous rocks Landslips of Kent Mesozoic Metamorphic rocks Museums Mineralogy Mining Natural disasters Palaeogeography Palaeozoic Petroleum Planetary geology Plate tectonics Precambrian Sedimentary rocks Stratigraphy Structual geology
Structural Geology Lab. (Page 8) It deals with geologic structures (faults and folds) that form when stresses (tension, compression, shear) act upon a body of rock. http://www.geo.utexas.edu/courses/303/303_Lab/StructureLab303.html
Extractions: Structural Geology Lab Quick Access Main Page Minerals Igneous Sedimentary ... Hydrogeology Last Modified: Overheads shown in Lab Structural Geology is perhaps one of the hardest subjects for beginning geology students to learn. It deals with geologic structures (faults and folds) that form when stresses (tension, compression, shear) act upon a body of rock. The difficulty is that it requires that the student think in 3-D which is a difficult skill to learn. However, there is hope! Knowing a few simple rules (and a lot of terminology) can allow even the beginning geologist to handle some rather complex structural problems. Let's get to it! Terms to Know Broken Rocks Folded Rocks Map Symbols ... Block Diagrams Unconformity Stress and Strain Compression Tension Shear Strike Dip Joint Fault Slickensides Normal Fault Reverse Fault Thrust Fault Axial Plane Fold Axis Limb Fault Plane Horst/Graben * Up to Structural Geology Topic List * Joint : A break in a rock (crack) in which there is no relative movement of either side across the break.
Geological Faults Geological faults. Geological faults. Fault Diagram. A fault is a discontinuity in a rock mass; locally it can be seen as a plane. http://www.hanksville.org/daniel/geology/faults.html
Extractions: Geological faults A fault is a discontinuity in a rock mass; locally it can be seen as a plane. It is along this surface that stresses buily up in the earth's crust are relieved by the motion of the two bodies of rock with respect to each other, i.e. an earthquake. The names for the two blocks are derived from old mining nomenclature. The block on top along the fault is known as the hanging wall; the block on the bottom is called the footwall. In a normal fault, the stress is caused by stretching or extension of the earth's crust. In this case the hanging wall moves downward with respect to the footwall. This is the way most of the mountain ranges have been formed. A reverse fault is caused by compression of the earth's crust. In this case, the footwall moves down with respect to the hanging wall. Thrust faults are also activated by compression of the earth's crust. However, in this case, only the relatively thin upper layers take part in the motion. In the case of the overthrust belt in western Wyoming, the first thrust fault developed was the westernmost. Succeeding faults developed to the east. It is usually the case that the thrust faults converge into a single fault at deeper layers.
THE GEOLOGIC SETTING How does this behavior fit into what we know of the geology of the area? These are arcuate, convexsouthward reverse faults which separate the http://www.johnmartin.com/earthquakes/eqpapers/00000019.htm
Extractions: from California Geology, April/May 1971, Vol. 24, No. 4-5. Special San Fernando Earthquake Edition THE GEOLOGIC SETTING By Gordon B. Oakeshott How does this behavior fit into what we know of the geology of the area? What has been the history of development of this great mountain range which lies in the central part of the Transverse Ranges of southern California? Particularly, what has been the late history of faulting, folding, and mountain-building in this region? The rocks Rock formations in the San Gabriel Mountains include most major rock types in great variety, ranging from Precambrian igneous and metamorphic rocks to Holocene (Recent) alluvium. The Precambrian crystalline rocks consist principally of anorthosite and related types, radiometrically dated as 1.2 billion years old, which have intruded the 1.4 billion-year-old Mendenhall Gneiss. The Precambrian rocks are found mainly north of the San Gabriel fault. Mesozoic granitic rocks, at least some of which have been dated at about 70 million years old, crop out both north and south of the San Gabriel fault. South of the fault they carry some inclusions of Paleozoic(?) igneous and metamorphosed sedimentary rocks. The crystalline rocks which form the central core in the highland part of the San Gabriel range are flanked on the north, west, and south by overlying younger Tertiary sedimentary and volcanic rock formations. Small bodies and fragments of Paleocene (60-70 million years old) marine sandstone and conglomerate have been sliced into the San Gabriel fault zone. Paleocene to middle Eocene marine sandstone and conglomerate occur at the extreme western end of the range.
Earthquakes Module 5 Environmental Geology The earthquake s location, magnitude of the earthquake, surface geology, Earthquakes result from movement along a fault. faults and earthquakes are http://wapi.isu.edu/envgeo/EG5_earthqks/eg_mod5.htm
Extractions: by Anni Watkins E a r t h q u a k e s are probably the most frightening naturally occurring hazard encountered. Why? Earthquakes typically occur with little warning. There is no escape from an earthquake! Earthquakes have devastating effects, resulting in hundreds to thousands of deaths and injuries, and millions to billions of dollars worth of property damage. The earthquake's location, magnitude of the earthquake, surface geology, and population density are major factors contributing to earthquake damage. Earthquakes result from movement along a fault. Faults and earthquakes are cause and effect. The sense of motion on faults describes how the block move relative to each other. Faults may move along preexisting fracture or may form a new one. There are 3 basic types of faults: normal, reverse, and strike-slip. Normal and reverse faulting result in vertical slip, while strike-slip faulting results in horizontal slip. In nature, motion is seldom absolutely along one direction. There can be a combination of vertical and horizontal slip, which would make the movement along the fault oblique. Normal faults are associated with extension. A good example of normal faulting is the Basin and Range topography of the western United States. The western part of the North American plate has been pulled apart into a series of "blocks". Most Basin and Range structures result from the tilting of these blocks. A major Basin and Range fault zone is the Wasatch Fault zone, which is 220 miles long (360 kilometers) and extends from Utah into Idaho.
Geology Class Notes Reverse faults are the result of compressional stress. A normal is downward dipslip Any break in the sedimentary geologic record is an unconformity, http://ruby.colorado.edu/~smyth/G1010-10.html
Extractions: Stress is the applied force. Strain is the resultant deformation. Stress can be compressional, tensional, shear, or isostatic. All applied stresses cause rock (or any other solid) to deform (strain). Strain can be elastic or plastic. If a material undergoes continuous plastic deformation, it is said to be ductile . If it fractures, it is said to be brittle Fig 16.1. Split Mountain Anticline, Dinosaur National Monument, Colorado. This is an example of a plunging, anticlinal fold in Paleozoic and Mesozoic sedimentary rocks. The river is the Green just below its confluence with the Yampa. There are also some pre-Cambrian sediments exposed in the core of this classic anticline, upstream of this photo. Sedimentary rocks that deform plastically are said to form folds A syncline is a concave-upward fold.
Bodega Head Geology Their studies of that site indicated that there were no active faults in the However, during construction, geologists found a new fault 5 miles off http://www.sonoma.edu/geology/wright/Bhead.html
Extractions: Bodega Bay is a natural harbor resulting from movement along the San Andreas Fault. The eastern shore is straight and parallel to the edge of a wide zone of faulting that extends across the bay to the hills on Bodega Head. During the 1906 earthquake, 15' of movement displaced the harbor to the north relative to the mainland. Downward movement of the fault zone and erosion of rocks shattered by faulting gave us the depression of the bay. A sand spit closes the bay to the south at Doran Beach and a wide reach of sand dunes forms a northern barrier along Salmon Creek Beach. The rock contrast across the fault is profound. We see oceanic rocks of the Franciscan Complex Complex to the east and continental granites exposed on Bodega Head, a fragment of southern California or perhaps Baja California dragged north along the fault. If we try to match rocks from Bodega Head to rocks east of the fault, we have to go at least to the Tehachapi Mountains, 500 Km to the south to find similar granites. Some people feel the match is best in Baja California, several thousand Km to the south. Besides the many attractions of good food and tourism, natural attractions abound. The Bodega Marine Lab, run by the University of California has tours friday afternoons and many ongoing research programs on marine biology. The beaches and landscape surrounding the bay are a natural lab for geology and biology.
USGS Geology In The Parks faults and earthquakes. Like most stories in geology, this one starts beneath the surface. As you may know, the continents we live on are parts of moving http://wrgis.wr.usgs.gov/docs/parks/deform/gfaults.html
Extractions: Fault scarp Like most stories in geology, this one starts beneath the surface. As you may know, the continents we live on are parts of moving plates . Most of the action takes place where plates meet. Plates may collide, pull apart, or scrape past each other. All the stress and strain produced by moving plates builds up in the Earth's rocky crust until it simply can't take it any more. All at once, CRACK!, the rock breaks and the two rocky blocks move in opposite directions along a more or less planar fracture surface called a fault The sudden movement generates an earthquake at a point called the focus . The energy from the earthquake spreads out as seismic waves in all directions. The epicenter of the earthquake is the location where seismic waves reach the surface directly above the focus.
USGS Geology In The Parks When faults extend to the Earth s surface, displacing parts of the landscape, and learn some of the terminology used by geologists to describe faults. http://wrgis.wr.usgs.gov/docs/parks/deform/7faults.html
Extractions: Open-file Report 90-257A This report is preliminary and has not been reviewed for conformity with U.S. Geological Survey editorial standards. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this program has been used by the U.S. Geological Survey, no warranty, expressed or implied, is made by the USGS as to the accuracy and functioning of the program and related program material, nor shall the fact of distribution constitute any such warranty, and no responsibility is assumed by the USGS in connection therewith. *U.S. Geological, Survey, Menlo Park, CA 94025 Figure 1. Simple fault types. Figure 2. Complex fault types. Fault surface is curved, resulting in block tilting
Utah Earthquakes & Faults - Utah Geological Survey The Utah Geological Survey investigates and reports on Utah s geologic hazards, mineral, energy, water, and paleontological resources, maps the state s http://geology.utah.gov/utahgeo/hazards/eqfault/
Extractions: 2003 International Building Code, 0.2 and 1 second spectral response acceleration maps Ground-shaking map for a magnitude 7.0 earthquake on the Wasatch fault, Salt Lake City, Utah, metropolitan area (pdf) Public Information Series #76 Earthquake ground shaking in Utah (pdf) Public Information Series #29 What are seismic surveys Survey Notes Recent Utah Earthquakes - UUSS Catalog Summary Photo essay of four Utah earthquakes, 1921-1972 (pdf) Public Information Series #72 Homebuyers guide to earthquake hazards in Utah (pdf) Public Information Series #38 (pdf) Public Information Series #48