It began with thrusting on the previously unrecognized Susitna Glacier fault, continued with right-slip … Earthquake hazards Ground Rupture Alaskan pipe after the Denali quake ruptured through Ground rupture from the M8.1 2001 Tibet earthquake Earthquake hazards (cont.) We know a fault exists only if it has produced an earthquake or it has left a recognizable mark on the earth’s surface. Earthquake forecasting and prediction is an active topic of geological research. The southern edge of our state is an active tectonic plate boundary where the Pacific plate subducts (i.e., dives beneath) the North American plate along the great Alaska-Aleutian Megathrust. Postseismic deformation is the general term used for the movements that follow and are triggered by earthquakes. If the automatic location algorithms indicate a large earthquake, the seismologist on duty responds immediately (seismologists are on call 24/7) and issues an information release—in part to help emergency management personnel respond to significant events. Earthquake Risk in Alaska. On average, Alaska has had one M 8+ earthquake every 13 years, one M 7-8 earthquake every two years, and six M 6-7 earthquakes per year (Alaska Seismic Hazards Safety Commission, 2012). Before allowing the installation of scientific equipment in a national park (via research permit), staff from the park conduct an impact study and provide a period for public comment. Therefore, in the pre-earthquake phase, preparedness, mitigation and prevention The Kantishna cluster is a group of small, shallow earthquakes—not far from Wonder Lake—at the southwestern end of a shear zone. The Denali Fault has a lower seismic risk, with a maximum of the Denali fault earthquake, with clockwise rotation ranging from about 14 in the western part of the rupture to as much as 38 in the eastern part. COUNTERMEASURES AGAINST LARGE-SCALE EARTHQUAKES The main cause of many casualties in the Hyogoken Nambu Earthquake in 1995 was earthquakes, including the 1964 Prince William Sound 9.2 earthquake. The November 3, 2002 Denali fault earthquake, which is the largest inland event ever recorded in central Alaska, occurred along an arcuate segment of the right‐lateral strike‐slip Denali fault. The largest surface offsets of 8.8 meters (29 feet) were observed farther to the east. Deep earthquakes occur under the ground in the southern and eastern portions of the park (see red-orange and orange dots on the map above). The typical example of this kind of earthquake was the Hyogoken Nambu Earthquake in 1995, the Niigataken Chuetsu Earthquake in 2004, and the Noto Hanto Earthquake in 2007. During the afternoon of November 3, 2002, the water in Seattle’s Lake Union suddenly began sloshing hard enough to knock houseboats off their moorings. Studies of the fault at various locations have yielded a wide range of slip rates, but the best estimates generally converge on a maximum rate of about 10 mm/yr. Areas affected by liquefaction are largely confined to Holocene alluvial deposits, man-made embankments, and backfills. Using the program FPFIT [Reasenberg and Oppenheimer, 1985], Ratchkovski et al. Geologist Wes Wallace of the University of Alaska s Geophysical Institute took this photo of the Denali Fault before the earthquake. Such knowledge is needed to predict ground motions in future earthquakes so that earthquake-resistant structures can be designed. The 2002 Denali, Alaska Earthquake. McKinley) that dominates the park landscape. The Good Friday Earthquake—a 1964 magnitude 9.2 event located in Prince William Sound—remains the largest earthquake ever recorded in the U.S. and the secondlargest earthquake ever recorded worldwide. Largest aftershocks of the Nenana Mountain earthquake were the two magnitude 3.8 events. 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 main shock occurred about 80 km (50 miles) east of the Denali Visitor Center. Automatic locations are available within five minutes on AEIC’s webpage. al., 1994]. Until then, the fault can be studied by measuring the steady deformation of the Earth that surrounds all active faults. One example of a major fault is the Denali fault, which cuts across the state in the Alaska Range (labelled on map on reverse). For example, there were clusters of earthquakes around a zone that included a major earthquake on Jan 30, 1973, another cluster around an earthquake of March 14, 1979, and two more cluster around earthquakes of July 1957 and January, 1962. [2004] determined focal mechanisms for earthquakes before and after the Denali fault earthquake, then estimated Hayes through the Alaska Range, and the ovals are the epicenters of two earthquakes, the magnitude 6.7 earthquake of Oct. 23, 2002, and the Denali Fault earthquake of Nov. 3, 2002. Remove maintenance message Even several years after the earthquake, average speeds remain several times higher than the pre-earthquake rates at many sites. Denali fault earthquake to evaluate structural damage in that event. The Pacific plate is moving northwest relative to Alaska, causing many earthquakes along the interface. Place an order for a custom essay, research paper on this or related subject. 94, no. The destruction caused by an earthquake depends on the magnitude and … Continue reading "Mitigation of Earthquakes" The AEIC located over 1,000 aftershocks of the M 6.7 event prior to the M 7.9 mainshock and over 35,000 aftershocks through the end of 2004. This presents a rare opportunity to catch a major earthquake in the act. By continuing to browse this site you agree to us using cookies as described in About Cookies.. Major earthquakes (those with a magnitude range of 7.0-7.9) occur where a significant amount of stress has accumulated prior to being released—along a plate boundary or along major faults. High precision Global Positioning System (GPS) surveying can now measure positions of survey points with a precision of a few millimeters. AEIC analysts locate between 20,000 and 30,000 earthquakes in Alaska each year. The evaluation of the seismic risk is considered essential to define strategic urban and emergency planning management actions and should be based on the analysis of the buildings, the exposed population and their emergency interaction. ... slightly larger than the magnitude 9.0 Sumatra-Andaman Islands earthquake that devastated northern Sumatra in December 2004 and generated a tsunami that killed more than 280,000 people. 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 pattern of shallow, intermediate, and deep events in south-central Alaska highlights the shallow angle of the subduction. The 2002 M7.9 Denali fault earthquake resulted in 340 km of ruptures along three separate faults, causing widespread liquefaction in the fluvial deposits of the alpine valleys of the Alaska Range and eastern lowlands of the Tanana River. This seismically active area in the heart of the park typically experiences a M 2 earthquake every few days. Areas affected by liquefaction are largely confined to Holocene alluvial deposits, man-made embankments, and backfills. Eastern Denali Fault surface trace map, eastern Alaska and Yukon, Canada. One of them was the Denali 7.9 earthquake, the largest earth- OCLC Number: 64385498: Notes: Title from Web page (viewed Feb. 24, 2006). Earthquake - Earthquake - Methods of reducing earthquake hazards: Considerable work has been done in seismology to explain the characteristics of the recorded ground motions in earthquakes. Water in pools, ponds, and bayous as far away as Texas and Louisiana splashed for nearly half an hour. S58–S71, 2004. Ongoing tectonic processes are constantly shifting and changing the land. Edwards, M. Rahman, H. Ryu, ... the second was close to the community of Mundaring east of the Darling fault. Denali National Park is located very close to the Denali fault. Understanding the risk and getting ready for a large earthquake on the Hayward Fault like the one depicted in this scenario can help other at-risk communities prepare for similar events that are possible in their area. 3 November 2002 Denali Fault earthquake, a large-magnitude (M=7.9) shallow strike-slip event, generated large-amplitude surface waves observable by GPS to a distance of thousands of kilometers [Larson et al, 2003]. The pipeline crosses the Denali fault some 90 miles south of Fairbanks. 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. The 800-mile-long Trans-Alaska Pipeline, which starts at Prudhoe Bay on Alaska’s North Slope, can carry 2 million barrels of oil per day south to the port of Valdez for export, equal to roughly 10% of the daily consumption in the United States in 20171. The Denali Fault earthquake sequence resulted in about 340 km of surface rupture (Haeussler and others, 2004) (figs. View at: Google Scholar To understand the risk that different areas of the U.S. face for earthquake hazards, we need to know where faults are and how they behave. > $7 billion dollars damage Reasons for huge loss….. The criteria consisted of location, type, and amount of fault displacement at the Denali and other fault crossings. 6, pp. Once a fault has been identified, the next step is to determine how it behaves. We map the 385-kilometer (km) long surface trace of the right-lateral, strike-slip Denali Fault between the Totschunda-Denali Fault intersection in Alaska, United States and the village of Haines Junction, Yukon, Canada. Alaska not only experiences the most earthquakes in the United States, but also the strongest. During this reporting period, the NEHRP celebrated its 25th anniversary. 2 San Andreas ... Denali fault, Alaska Magnitude 7.9 2002 ... 2004 2010 2011. To monitor seismic activity, staff from the Alaska Earthquake Information Center (AEIC) install and operate seismic stations across the state. 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). Largest aftershocks of the Nenana Mountain earthquake were the two magnitude 3.8 events. BACKGROUNDER • ASSESSING AND MANAGING SEISMIC RISK. The red line represents the fault, which runs east toward Mt. Alaska has experienced four federally declared disasters from November 2002 to August 2003. A T eleseismic Study of the 2002 Denali Fault, Alaska, Earthquake and Implications for Rapid Strong-Motion Estimation Chen Ji,a) Don V .Helmber ger,a) and Da vid J.W ald, b) M.EERI Slip histories for the 2002 M7.9 Denali fault, Alaska, ear thquak e are de-rived rapidl y from global teleseismic w avefor m data. practice into seismic risk reduction. However, full ANSS instrumentation on either end of the 2002 rupture is critical if this goal is to be achieved. Large earthquakes like this one cause significant displacements of the surface far away from the fault. The Nenana Mountain and Denali Fault earthquakes generated a vigorous aftershock sequence. Pacific Nankai h Metropolitan 3. It was the main fault along which the 2002 Denali earthquake occurred, which was measured as a magnitude of 7.9 M w. During the afternoon of November 3, 2002, the water in Seattle's Lake Union suddenly began sloshing hard enough to knock houseboats off their moorings. But once in awhile, we experience larger earthquakes too; in 1868, Kaʻū experienced a quake estimated at M 7.9 that knocked down every wall and building in the district, and took the lives of 81 … It is unknown whether some of this stress is being relieved by the cluster of frequent shallow earthquakes in the Kantishna area. Complex, powerful motions of tectonic plates and crustal blocks generate earthquakes throughout Alaska, including many in and around Denali National Park and Preserve. The section of the Denali fault cutting across the park has not experienced a major earthquake within the last ~100 years. One example of a major fault is the Denali fault, which cuts across the state in the Alaska Range (labelled on map on reverse). Although the fault there shifted about 14 feet, the pipeline did not break, averting a major economic and environmental disaster. G. Carver, G. Plafker, M. Metz et al., “Surface rupture on the Denali Fault interpreted from tree damage during the 1912 Delta river Mw 7.2–7.4 earthquake: implications for the 2002 Denali Fault earthquake slip distribution,” Bulletin of the Seismological Society of America, vol. of the Denali fault earthquake, with clockwise rotation ranging from about 14 in the western part of the rupture to as much as 38 in the eastern part. 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. Fortunately, no one was seriously injured, due to the small population located Alaska’s Denali Fault was on the move, jostling the state with a magnitude 7.9 earthquake. 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. April 9 2004 Rev F Page 1 Oil and Water System Performance – Denali M 7.9 Earthquake of November 3, 2002 By John Eidinger1 and Mark Yashinsky2 1.0 Introduction The November 3, 2002, magnitude 7.9 Denali, Alaska earthquake struck through rural Alaska. BACKGROUNDER • ASSESSING AND MANAGING SEISMIC RISK. The longest earthquake ruptures on strike-slip faults, like the San Andreas Fault (1857, 1906), the North Anatolian Fault in Turkey (1939) and the Denali Fault in Alaska (2002), are about half to one third as long as the lengths along subducting plate margins, and those along normal faults are even shorter. The 1964 Good Friday Earthquake is an example. The 2002 Denali Fault earthquake caused changes in the observed motions all across central Alaska. Each seismic station transmits data to Fairbanks, where seismologists continuously monitor ground motion. and minor earthquakes on the subduction zone in a cluster pattern. A network of 26 1-Hz GPS stations that observed sur-face wave displacements due to the Denali Fault event Alaska is the most geologically active part of the United States. The National Hazard Maps use all available data to estimate the chances of shaking (of different strengths and Investigating the seismic response of regular and irregular urban structures can provide useful information for input to any preparedness plan. The evaluation of the seismic risk is considered essential to define strategic urban and emergency planning management actions and should be based on the analysis of the buildings, the exposed population and their emergency interaction. Abstract An earthquake can be described as natural phenomena that cause shaking or trembling of the earth’s surface. Earthquakes shake the ground daily, but most are minor local events. Analysts also scan waveforms to find earthquakes that were not detected by the automated system. Measuring the deformation of the earth related to this tectonic activity helps scientists understand the 2002 earthquake and the tectonic forces that caused it. About Cookies, including instructions on how to turn off cookies if you wish to do so. Hazard estimates have important implications for society, providing a basis for building codes, insurance rate structures, risk assessments, and public policies to mitigate earthquake risk. [4] The Denali fault earthquake had 340 km of surface rupture and was the largest strike-slip earthquake in North The epicenter was located west of Nenana Mountain on the Denali fault… The basic structure of methods for estimating hazard was developed by engineers needing quantitative answers despite the wide range of uncertainties ( 1 ). Seismicity in interior Alaska north of the Denali fault is dominated by shallow events (see blue dots on map above). The interaction of the Pacific and North American plates across southern Alaska creates a variety of sources for seismic activity. Such approach is urgently needed for complex scenarios, like the historical one, but still, in many cases around the world, historical centers scenarios are not properly investigated according this holistic risk analysis standpoint. The epicenters (point on the earth surface where the quakes originate) of each of these large earthquakes was about 50 km (30 miles) east of the park, on the Denali fault. Effect of the Denali Fault Rupture on the Trans-Alaska Pipeline ; Response of the Above-Ground Trans-Alaska Pipeline to the Magnitude 7.9 Denali Fault Earthquake ; Assessment of the Below-Ground Trans-Alaska Pipeline Following the Magnitude 7.9 Denali Fault Earthquake earthquake, which would result in a maximum PGA of 0.17g at Pebble. Earthquakes can cause impacts far from their source. At many of the sites inside the park, the motions after the 2002 earthquake are now slowing down to nearly the preearthquake rates. 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. It illuminates earthquake mechanics and hazards of large strike-slip faults. Called the Denali Fault earthquake, this shock was the strongest ever recorded in the interior of 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). Following the Mw 7.9 earthquake on the Denali and Totschunda faults on 3 November 2002, we conducted a reconnaissance of the region to investigate geotechnical and surface rupture features of the event. On average, Alaska has had one M 8+ earthquake every 13 years, one M 7-8 earthquake every two years, and six M 6-7 earthquakes per year (Alaska Seismic Hazards Safety Commission, 2012). around the Denali fault is sparsely populated, it is the same type of fault as the San Andreas fault in California, which is surrounded by densely populated cities. These trained individuals greatly enhanced our State Post-Disaster Damage Assessment team's capability and credibility. Effect of the Denali Fault Rupture on the Trans-Alaska Pipeline ; Response of the Above-Ground Trans-Alaska Pipeline to the Magnitude 7.9 Denali Fault Earthquake ; Assessment of the Below-Ground Trans-Alaska Pipeline Following the Magnitude 7.9 Denali Fault Earthquake These quakes are associated with the northern extension of the subduction edge of the Pacific plate and its dive beneath the North American crust. The major plates move relative to each other at rates that are typically a few centimeters per year, which is easily measured using GPS. The 434 mile slip-strike fault gave off a 7.9 magnitude earthquake. There have been smaller earthquakes in … Proceedings of the Sixth U.S. Conference and Workshop on Lifeline Earthquake Engineering, TCLEE 2003: Advancing Mitigation Technologies and Disaster Response, held in Long Beach, California, August 10-13, 2003. earthquake, which would result in a maximum PGA of 0.17g at Pebble. Note how the blue dots scattered at the top of the map track roughly northeast-trending parallel lines. Areas of active faulting like central Alaska continuously undergo slow deformation between earthquakes, and experience sudden shifts when earthquakes happen. In the Aleutian Islands, where the subduction angle is much steeper, the shallow-todeep earthquake pattern is more compact. A major earthquake along the fault could cause the pipeline to rupture, spilling crude oil into the surrounding environment. The chances of experiencing shaking from an earthquake and/or having property damage is dependent on many different factors. It was the largest inland earthquake to hit North America in the last 150 years. 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. It was evident, during damage assessment evaluations after the Denali fault event, that the residents of the smaller at-risk communities had little understanding of the earthquake hazard, had not implemented measures to mitigate damage, and were unprepared to respond to the consequences of damage. Overall, motions were about 20 times faster over the first 1-2 years after the earthquake, compared to the pre-earthquake rates. All the atmospheric parameters [CWV, SLHF, relative humidity (RH) and total ozone column (TOC)] show significant changes prior and after the Denali fault earthquake. Earthquake Hazards Mitigation Here on the Big Island, we feel small earthquakes on a regular basis, and magma movement underground that precedes eruptive activity produces low-level tremor. In 2002, the M 7.9 earthquake ruptured a portion of the Denali fault east of the park to produce a horizontal offset of up to 8.8 m (29 feet). The Nenana Mountain and Denali Fault earthquakes generated a vigorous aftershock sequence. Geoscientists are able to identify particular areas of risk and, if there is sufficient information, to make probabilistic forecasts about the likelihood of earthquakes happening in a specified area over a specified period. Faulting like central Alaska continuously undergo slow deformation between earthquakes, and bayous as far away from the Denali other! 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