Download or read book A Three dimensional Gravity Model of the Geologic Structure of Long Valley Caldera written by and published by . This book was released on 1987 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Several attempts to define and interpret this anomaly have been made in the past using 2-D and 3-D models. None of the previous interpretations have yielded definitive results, but in fairness, the interpretation here has benefited from a larger gravity data base and more subsurface control than available to previous workers. All published 3-D models simplistically assumed constant density of fill. All 2-D models suffered from the inherent three-dimensionality of the complicated density structure of Long Valley caldera. In addition, previous interpreters have lacked access to geological data, such as well lithologies and density logs, seismic refraction interpretations, suface geology, and structural geology interpretations. The purpose of this study is to use all available gravity data and geological information to constrain a multi-unit, 3-D density model based on the geology of Long Valley caldera and its vicinity. Insights on the geologic structure of the caldera fill can help other geophysical interpretations in determining near-surface effects so that deeper structure may be resolved. With adequate control on the structure of the caldera fill, we are able to examine the gravity data for the presence of deeper density anomalies in the crust. 20 refs., 7 figs.
Download or read book Three dimensional Gravity Modeling of the Geologic Structure of Long Valley Caldera California written by Steven Farran Carle and published by . This book was released on 1986 with total page 108 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1988 with total page 666 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.
Download or read book Caldera Volcanism written by Joachim Gottsmann and published by Elsevier. This book was released on 2011-09-22 with total page 517 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume aims at providing answers to some puzzling questions concerning the formation and the behavior of collapse calderas by exploring our current understanding of these complex geological processes. Addressed are problems such as:- How do collapse calderas form? - What are the conditions to create fractures and slip along them to initiate caldera collapse and when are these conditions fulfilled? - How do these conditions relate to explosive volcanism?- Most products of large caldera-forming eruptions show evidence for pre-eruptive reheating. Is this a pre-requisite to produce large volume eruptions and large calderas?- What are the time-scales behind caldera processes? - How long does it take magma to reach conditions ripe enough to generate a caldera-forming eruption?- What is the mechanical behavior of magma chamber walls during caldera collapse? Elastic, viscoelastic, or rigid? - Do calderas form by underpressure following a certain level of magma withdrawal from a reservoir, or by magma chamber loading due to deep doming (underplating), or both?- How to interpret unrest signals in active caldera systems?- How can we use information from caldera monitoring to forecast volcanic phenomena?In the form of 14 contributions from various disciplines this book samples the state-of-the-art of caldera studies and identifies still unresolved key issues that need dedicated cross-boundary and multidisciplinary efforts in the years to come. - International contributions from leading experts - Updates and informs on all the latest developments - Highlights hot topic areas and identifies and analyzes unresolved key issues
Download or read book Energy Research Abstracts written by and published by . This book was released on 1992-03 with total page 358 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Geodetic And Geophysical Effects Associated With Seismic And Volcanic Hazards written by José Fernandez and published by Springer. This book was released on 2012-12-06 with total page 324 pages. Available in PDF, EPUB and Kindle. Book excerpt: Although geodetic monitoring techniques have been widely used in areas of seismic or volcanic activity, the difficulty inherent to their discrete nature means that they must be deployed carefully to ensure the best possible detection or sensitivity of these points (see e. g. , BALDI and UNGUENDOLI, 1987; JOHNSON and WYATT, 1994; SEGALL and MATTHEWS, 1997; Yu et al. , 2000). In many cases, a more global monitoring method, is required yet at the same time one that offers the highest level of sensitivity which enables detection of the phenomenon. Interferometry radar (InSAR) techniques have been shown to play an important role in seismic and volcanic monitoring because they cover large areas (100 x 100 km) and can be easily systematized in monitoring (see e. g. , MASSONNET and FEIGL, 1998; BDRGMANN et al. , 2000; MASSONNET and SIGMUNDSON, 2000; HANSSEN, 2001). The limitations inherent to the GPS and InSAR techniques (mainly observations at discrete surface points in the case of GPS and existence of non-coherent areas and the fact that, at present, the three displacement components cannot be obtained in SAR interferometry) can be overcome by using them together or other techniques (e. g. , PUGLISI and COLTELLI, 2001; RODRiGUEZ-VELASCO et al. , 2002; FERNANDEZ et al. , 2003).
Download or read book Gravity and Fault Structures Long Valley Caldera California written by and published by . This book was released on 1987 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The main and catastrophic phase of eruption in Long Valley occurred 0.73 m.y. ago with the eruption of over 600 km3 of rhyolitic magma. Subsequent collapse of the roof rocks produced a caldera which is now elliptical in shape, 32 km east-west by 17 km north-south. The caldera, like other large Quarternary silicic ash-flow volcanoes that have been studied by various workers, has a nearly coincident Bouguer gravity low. Earlier interpretations of the gravity anomaly have attributed the entire anomaly to lower density rocks filling the collapsed structure. However, on the basis of many additional gravity stations and supporting subsurface data from several new holes, a much more complex and accurate picture has emerged of caldera structure. From a three-dimensional inversion of the residual Bouguer gravity data we can resolve discontinuities that seem to correlate with extensions of pre-caldera faults into the caldera and faults associated with the ring fracture. Some of these faults are believed related to the present-day hydrothermal upflow zone and the zone of youngest volcanic activity within the caldera.
Download or read book List of U S Geological Survey Geologic and Water supply Reports and Maps for California written by Geological Survey (U.S.) and published by . This book was released on 1987 with total page 476 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book List of U S Geological Survey Geologic and Water supply Reports and Maps for California written by and published by . This book was released on 1987 with total page 476 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book New Publications of the Geological Survey written by Geological Survey (U.S.) and published by . This book was released on 1989 with total page 836 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book New Publications of the U S Geological Survey written by Geological Survey (U.S.) and published by . This book was released on 1995 with total page 100 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Long Valley Caldera Mammoth Lakes and Owens Valley Region Mono County California written by E. Joan Baldwin and published by . This book was released on 1999 with total page 402 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Volcanic Seismology written by Paolo Gasparini and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 580 pages. Available in PDF, EPUB and Kindle. Book excerpt: For many centuries people living on volcanoes have known that the outset of seismic activity is often a forerunner of a volcanic eruption. This understand ing allowed people living close to the sites of the Mt. Nuovo 1538 eruption at Campi Flegrei, Italy, and of the Mt. Usu 1663 eruption, in Hokkaido, Japan (to quote only two examples) to flee before the eruptions started. During the second half of the 19th century seismographs were installed on some volcanoes, and the link between seismic and eruptive activity started to be assessed on a firmer scientific basis. The first systematic observations of the correlations existing between seismic activity and volcanic eruptions were probably those carried out at Mt. Vesuvius by Luigi Palmieri in 1856. Palmieri was the Director of Osservatorio Vesuviano and built an electromagnetic seismograph with the aim of "making visible the smallest ground motions by recording them on paper and indicating direction, intensity and duration". He was able to show the relationship between earthquakes and the different phases of volcanic activity. He identified the harmonic tremor which he indicated was a precursor of volcanic activity: "the characteristic feature of the ground mo tions preceding eruption is its continuity . . . (before the eruption of 1861) the electromagnetic seismograph began to show a continuous tremor". The Palmieri seismograph was also utilized in Japan until 1883, when it was replaced by the new Gray-Milne seismographs, and, later, by the Omori in struments.
Download or read book Contact Metamorphism written by Derrill M. Kerrick and published by Walter de Gruyter GmbH & Co KG. This book was released on 2018-12-17 with total page 864 pages. Available in PDF, EPUB and Kindle. Book excerpt: Volume 26 of Reviews in Mineralogy provides a multidisciplinary review of our current knowledge of contact metamorphism. As in any field of endeavor, we are provided with new questions, thereby dictating future directions of study. Hopefully, this volume will provide inspiration and direction for future research on contact metamorphism. The Mineralogical Society of America sponsored the short course on Contact Metamorphism, October 17-19, 1991, at the Pala Mesa Resort, Fallbrook, California, prior to its annual meeting with the Geological Society of America.
Download or read book Physics Briefs written by and published by . This book was released on 1989 with total page 966 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book ERDA Energy Research Abstracts written by and published by . This book was released on 1989 with total page 848 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Stress Field Control of Eruption Dynamics written by Roberto Sulpizio and published by Frontiers Media SA. This book was released on 2017-10-10 with total page 133 pages. Available in PDF, EPUB and Kindle. Book excerpt: Increasing evidence supports the claim that stress changes play a fundamental role in triggering volcanic eruptions. Stress changes may vary in origin to include earthquakes, erosion and landslide processes, deglaciation, or tidal effects. The local stress can also change as response of magma influx from deeper reservoirs and an increase of the magma/gas pressure. The stress transfer may be of great importance in reawakening a dormant system. As an example, significant statistical correlation of large earthquakes and eruptions in time and space was suggested in many works. The interaction may be two-fold; where magma intrusions may change the stress at active faults and trigger earthquakes, while tectonic earthquakes may affect the magmatic system and change the eruption activity. The change in local tectonic stress has been claimed as trigger of large ignimbrite eruptions or for controlling the eruptive style of explosive eruptions. Sometimes volcano systems that are nested or closely located may become active in chorus; neighbouring volcanoes may interact in the sense that one volcano triggers its neighbouring volcano. However, although there is ample evidence of concurrence, the processes of interacting volcanoes and near- to far-field tectonic stress are not well understood. Some studies suggest that volcanic eruptions are triggered if compressive stress acts at the magma system and “squeezes” out magma. Other studies suggest that extensional stress fields facilitate magma rise and thus encourage eruptions, or that fluctuating compression and extension during the passing of seismic waves trigger eruptions. This research topic tries to address some of the important open questions in interaction between stress field and volcanic eruption, though both review papers and new contributions.
