The Denali Fault earthquake ruptured the Earth's surface for 209 miles, crossing beneath the vital Trans-Alaska Oil Pipeline, which carries 17% of the U.S. domestic oil supply. The Denali fault laterally offset pre-existing crevasses on the north side of the Canwell Glacier and vertical offset was observed at many localities. Two end-member tectonic models can be invoked to explain This shows that geologists still have questions about the deformation properties along the Denali fault. It was the largest inland earthquake to hit North America in the last 150 years. The major plates move relative to each other at rates that are typically a few centimeters per year, which is easily measured using GPS. According to Ford, “The Denali Fault earthquake was the ‘big one’ for Alaska.” The cracks in the Earth’s surface along parts of the fault were up to 6.7 meters (22 feet) wide, which would have caused considerable damage to a more heavily populated area, such as California. Because of its location close to the November 3 event and the fact that it preceded it by only 11 days, this earthquake is regarded as a foreshock that probably directly triggered the main shock. The 434 mile slip-strike fault gave off a 7.9 magnitude earthquake. 5, A and D). The Denali fault system forms an arc, convex to the north, across southern Alaska. The Denali Fault is located in Alaska's Denali National Park and to the east. Its total length is 1,700 km, and about 1,140 km of the fault has evidence for Quaternary move-ment (figure 3). The earthquake caused an offset of nearly 6 meters (20 feet) where it crossed the Richardson Highway and Trans-Alaska Pipeline. Tectonophysics, 47: 24773. Photo credit. Along the Denali Fault, lateral and vertical offset movement is taking place. At this time the Earth’s tectonic plates formed a single body named Rodinia, where much of present day Alaska was submerged under water (3). The largest surface offsets of 8.8 meters (29 feet) were observed farther to the east. This subduction contributed to the landscape through volcanic eruptions, and rising igneous minerals such as granite. Some geologists hypothesize that the body is moving with the Pacific plate, while approaching the DFS (. Using a model which simulates the subduction between the two tectonic plates, we can have a qualitative look at system velocities. 2; Haeussler et al., 2004). 2006). 0.4 m slip on the Susitna Glacier fault, between 1 and 9.5 km depth on a 29 km long fault that dips north at 41 0.7 and has a surface projection close to the mapped rupture. Denali, highest peak in North America. The modelling consists of meshes spanning 185 to 240 degrees longitude, and 45 to 72 degrees north latitude, where the DFS is. In terms of primary deformation, I believe these models show many characteristics of the DFS, but we are still limited in our deformation analysis. Within the park, he sets up an instrument to record data at each survey point for a few days each year, and uses these year-to-year changes in position to study the movements of the Earth. The formation of this unique segment is likely a result of thrusting from the suturing of the Wrangell and southern Alaska terrain (Ridgway, Kenneth D. et al 1997). Denali consists of a right lateral strike-slip fault over 720 miles long (Sharpe). On November 3, 2002 a devastating earthquake rattled Alaska. The November 2002 earthquake had a magnitude of 7.9 and caused a surface rupture 325 km (~200 miles) long, mostly on the central Denali Fault (see red line on map below). Flat slab subduction is present in the cross section BB’, which is located underneath the fault system (Jadamec, Margarete A. et al 2013). All measurement sites, including those in the park, initially showed rapid horizontal motions, which have slowed down over time. One of these is the Denali Fault, a dextral 2000-km-long strike-slip structure that traverses the rugged Alaska Range of south central Alaska for about 780 km. There are only a few number of models which can adequately describe the DFS, one being an overriding and subduction plane, combined with the underlying mantle. All three were changed around the same century. It is located near the centre of the Alaska Range, with two summits rising above the Denali Fault, in south-central Alaska, U.S. Denali’s official elevation figure of 20,310 feet (6,190 metres), established by the United States Geological Survey in September Trace of the Denali Fault after the 7.9 magnitude earthquake of 3 November 2002, Alaska, USA. High precision Global Positioning System (GPS) surveying can now measure positions of survey points with a precision of a few millimeters. Another notable geological feature is that the fault system has essentially isolated a portion of the North American Plate. The largest inland earthquake in North America in almost 150 years struck Alaska on November 3, 2002. "Thrust-top basin formation along a suture zone, Cantwell basin, Alaska Range: Implications for development of the Denali fault system. The most recent age estimate of this formation is the Paleocene era, dating back between 56 and 66 million years ago. One key geological feature of the DFS is the Cantwell Formation, a combination of two bedding outcrops that compose much of the fault. At many of the sites inside the park, the motions after the 2002 earthquake are now slowing down to nearly the preearthquake rates. In order to paint a better picture, models are used to simulate tectonic movement over millions of years. Most people in Interior Alaska were reminded of the fault’s earthquake potential when it ruptured on November 3, 2002. The Denali Fault is a long, tectonically active region that snakes through Alaska’s southern interior. The Denali Fault System, DFS, has a geological beginning dating back approximately a billion years. The section of the fault in the park is just as active as the section to the east, and at some point in the future it will also break in a large earthquake. Age estimates were determined through the interpretation of fossil plant leaves present in the lower bedding (, After a long time period of island collision events, volcanic activity took over creating the geological system. The upper outcrop is a volcanic unit, composed of intercalated andesite, rhyolite, basalt flows, and some pyroclastic rocks. When the Volturi found out, they came to destroy the entire group but Arochose to spare the sisters, since they knew nothing about the child. The Denali Fault System is responsible for many interesting geological features, ranging from the highest altitude in North America, to the Wrangell block. Around 300 million years ago these islands began to collide with the southwest coast of Alaska, bringing with it a distinct Aleutian terrane. These unique conditions may have in fact changed Wrangell Block motion with respect to its North American plate. -Ridgway, Kenneth D., Jeffrey M. Trop, and Arthur R. Sweet. The Denali Fault, the fastest moving and most active fault in Interior Alaska, cuts through the heart of the Alaska Range and Denali National Park and Preserve. Rutland (Editors), Structural Characteristics of Tectonic Zones. Measurements Freymueller has made across the Alaska Range before the 2002 earthquake show movement across the Denali Fault of 6-8 millimeters per year (1/4 to 1/3 inch per year). Only one instru-ment, pump station 10 (PS10), maintained by the Alyeska Pipeline Service Company, recorded near-source ground motions. It is convenient to view the fault as a single curve, but it is actually comprised of clusters of fault patterns. initiated at 22:12:41.0 UTC on the Susitna Glacier thrust fault before subse-quently transferring onto the Denali fault. The Denali Fault is located in Alaska's Denali National Park and to the east. The recent activity of the Denali fault system was demonstrated by the 2002 M7.9 Denali fault earthquake sequence (Eberhart-Phillips et al., 2003), which ruptured three intersecting faults of this system by initiating on the Susitna Glacier fault, stepping onto and rupturing 226 km of the Denali fault, and then transferring onto the Totschunda fault (Fig. The November 2002 earthquake had a magnitude of 7.9 and caused a surface rupture 325 km (~200 miles) long, mostly on the central Denali Fault (see red line on map below). "Three-dimensional numerical models of flat slab subduction and the Denali fault driving deformation in south-central Alaska. Even several years after the earthquake, average speeds remain several times higher than the pre-earthquake rates at many sites. Combined with geological investigations of past earthquake ruptures on this section of the fault, these studies will allow a better assessment of the earthquake hazards posed by this significant fault. The Denali fault earthquake produced long-duration, long-period motion, which is important in causing damage to tall buildings and bridges because it can shake them near their long natural periods. In central Alaska the Denali Fault has often been approximated by a small circle and is sometimes modelled as a rotating block (Fletcher 2002; Freed et al. According to Ford, “The Denali Fault earthquake was the ‘big one’ for Alaska.” The cracks in the Earth’s surface along parts of the fault were up to 6.7 meters (22 feet) wide, which would have caused considerable damage to a more heavily populated area, such as California. Between this time period and the formation of Pangea, islands were formed from spreading centers in the Earth’s crust, and began converging towards Alaska. "Deformation of the 2002 Denali Fault Earthquakes, mapped by Radarsat, http://www.facstaff.bucknell.edu/jtrop/Ridgway%20et%20al.,%201997,%20Cantwell.pdf, http://www.sciencedirect.com/science/article/pii/S0012821X13003257, http://onlinelibrary.wiley.com/doi/10.1029/2003EO410002/pdf, http://www.colorado.edu/engineering/GPS/bilich_bssa.pdf, http://gsabulletin.gsapubs.org/content/114/12/1480/F4.large.jpg, http://www.aeic.alaska.edu/Denali_Fault_2002/, https://www.youtube.com/watch?v=waRCongzBa4, https://www.youtube.com/watch?v=Npx8MK2Wyoo. Denali National Park is located very close to the Denali fault. This event was the largest strike-slip earthquake in North America in over 150 years (, The Denali Fault System is refereed to as such because there are numerous faults present. The crustal block south of the Denali Fault is called the Wrangell block, as defined by Lahr and Plafker [1980]. In this usage the Denali‐Totschunda intersection is 1.7 km long, the surface separation distance between the two faults is a maximum of 90 m, and the faults connect at the … McKinley) that dominates the park landscape. Although it is impossible to know with certainty the true nature of all system deformation, there are very accurate models which make a good illustration. This land mass is called the Wrangell Block, and has sparked some interesting models. The fault system has shown its slip potential in recent years, resulting in high magnitude in-land earthquakes. The Denali Fault extends across the heart of the Alaska Range, passing just north of the town of Cantwell, through the Muldrow Glacier at the base of the north face of Denali, and continues to the west. Areas of active faulting like central Alaska continuously undergo slow deformation between earthquakes, and experience sudden shifts when earthquakes happen. The three sisters then searched fo… The Totschunda fault is a 210-km-long splay of the Denali fault at its eastern end that strikes more southeasterly and is parallel Overall, motions were about 20 times faster over the first 1-2 years after the earthquake, compared to the pre-earthquake rates. Burns and R.W.R. 2005 Hokudan International Symposium on Active Faulting Surface Faulting Parameters • Total rupture length: 341 km Susitna Glacier fault (48 km long) Denali fault (226 km long) Totschunda fault (67 km long) • Surface Offsets Susitna Glacier fault (thrust; ~1-3 m vertical ave.) Denali fault (right lateral; 4.4-4.9 m ave.; max. Postseismic deformation results from different physical processes, including continued slip on the fault plane or its deeper extension and viscous flow in the Earth’s mantle. Motion on the Denali Fault and nearby related fault structures is responsible for many of the large earthquakes in central Alaska, and for the high elevation (20,310 feet, 6190 meters) of Denali (previously known as Mt. These velocities should be consistent with lateral movement along the fault. Located in south-central Alaska, the mountain's peak is 20,310 feet (6,190 meters) above sea level, also making it … The earthquake began about 80 km (50 miles) east of the Denali Visitor Center, and ruptured eastward along the Denali Fault, and was followed by thousands of aftershocks. The lower bedding outcrop is a primarily sedimentary unit, consisting of conglomerate, sandstone, siltstone, mudstone, and coal. At this time the Earth’s tectonic plates formed a single body named Rodinia, where much of present day Alaska was submerged under water (3). A branch point is the location on the surface where the trends of the principal fault traces diverge. 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