Advanced Geodynamics: Fourier Transform Methods
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Navigation and the Global Positioning System (GPS): the Global Positioning System
Navigation and the Global Positioning System (GPS): The Global Positioning System: Few changes of great importance to economics and safety have had more immediate impact and less fanfare than GPS. • GPS has quietly changed everything about how we locate objects and people on the Earth. • GPS is (almost) the final step toward solving one of the great conundrums of human history. Where the heck are we, anyway? In the Beginning……. • To understand what GPS has meant to navigation it is necessary to go back to the beginning. • A quick look at a ‘precision’ map of the world in the 18th century tells one a lot about how accurate our navigation was. Tools of the Trade: • Navigations early tools could only crudely estimate location. • A Sextant (or equivalent) can measure the elevation of something above the horizon. This gives your Latitude. • The Compass could provide you with a measurement of your direction, which combined with distance could tell you Longitude. • For distance…well counting steps (or wheel rotations) was the thing. An Early Triumph: • Using just his feet and a shadow, Eratosthenes determined the diameter of the Earth. • In doing so, he used the last and most elusive of our navigational tools. Time Plenty of Weaknesses: The early tools had many levels of uncertainty that were cumulative in producing poor maps of the world. • Step or wheel rotation counting has an obvious built-in uncertainty. • The Sextant gives latitude, but also requires knowledge of the Earth’s radius to determine the distance between locations. • The compass relies on the assumption that the North Magnetic pole is coincident with North Rotational pole (it’s not!) and that it is a perfect dipole (nope…). -
Download/Pdf/Ps-Is-Qzss/Ps-Qzss-001.Pdf (Accessed on 15 June 2021)
remote sensing Article Design and Performance Analysis of BDS-3 Integrity Concept Cheng Liu 1, Yueling Cao 2, Gong Zhang 3, Weiguang Gao 1,*, Ying Chen 1, Jun Lu 1, Chonghua Liu 4, Haitao Zhao 4 and Fang Li 5 1 Beijing Institute of Tracking and Telecommunication Technology, Beijing 100094, China; [email protected] (C.L.); [email protected] (Y.C.); [email protected] (J.L.) 2 Shanghai Astronomical Observatory, Chinese Academy of Sciences, Shanghai 200030, China; [email protected] 3 Institute of Telecommunication and Navigation, CAST, Beijing 100094, China; [email protected] 4 Beijing Institute of Spacecraft System Engineering, Beijing 100094, China; [email protected] (C.L.); [email protected] (H.Z.) 5 National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100094, China; [email protected] * Correspondence: [email protected] Abstract: Compared to the BeiDou regional navigation satellite system (BDS-2), the BeiDou global navigation satellite system (BDS-3) carried out a brand new integrity concept design and construction work, which defines and achieves the integrity functions for major civil open services (OS) signals such as B1C, B2a, and B1I. The integrity definition and calculation method of BDS-3 are introduced. The fault tree model for satellite signal-in-space (SIS) is used, to decompose and obtain the integrity risk bottom events. In response to the weakness in the space and ground segments of the system, a variety of integrity monitoring measures have been taken. On this basis, the design values for the new B1C/B2a signal and the original B1I signal are proposed, which are 0.9 × 10−5 and 0.8 × 10−5, respectively. -
GLY5455 Introduction to Geophysics/Geodynamics Syllabus Fall 2015 Instructor: Mark Panning Location: Williamson 218 Time: Tuesday and Thursday, 1:55-3:10Pm
GLY5455 Introduction to Geophysics/Geodynamics Syllabus Fall 2015 Instructor: Mark Panning Location: Williamson 218 Time: Tuesday and Thursday, 1:55-3:10pm Contact Info Office: 229 Williamson Hall Phone: 392-2634 Email: [email protected] Office hours: Can be arranged at any time via email Textbook Turcotte & Schubert, Geodynamics, 3rd Edition (required) We will also be pulling material from the following books (not required) Physics of the Earth, Stacey and Davis (2008) The Magnetic Field of the Earth, Merrill, McElhinny, and McFadden (1996) Introduction to Seismology, Shearer (2006) Pre-reqs You will ideally have completed 1 year of calculus and a semester of physics. This class will deal with vector calculus… if this worries you, check out div grad curl and all that, by H.M. Schey (available for around $30 online). Grading 60% Homework 20% Midterm 20% Final Course topics (roughly 2-3 weeks per topic… but very flexible!) Topic Text Gravity Ch. 5 + other notes Heat Ch. 4 Magnetism Material from The Magnetic Field of the Earth Seismology Ch. 2, 3, and material from Introduction to Seismology Plate Tectonics & Mantle Geodynamics Ch. 1,6,7 Geophysical inverse theory (if time allows) Outside readings TBA Class notes Lecture notes will be distributed, sometimes before the material is covered in lecture, and sometimes after. Regardless, as always, such notes are meant to be supplementary to your own notes. I may cover things not in the distributed notes, and likewise may not cover everything in lecture that is included in the notes. Homework The first homework assignment will be assigned in week 2. -
Geodynamics and Rate of Volcanism on Massive Earth-Like Planets
The Astrophysical Journal, 700:1732–1749, 2009 August 1 doi:10.1088/0004-637X/700/2/1732 C 2009. The American Astronomical Society. All rights reserved. Printed in the U.S.A. GEODYNAMICS AND RATE OF VOLCANISM ON MASSIVE EARTH-LIKE PLANETS E. S. Kite1,3, M. Manga1,3, and E. Gaidos2 1 Department of Earth and Planetary Science, University of California at Berkeley, Berkeley, CA 94720, USA; [email protected] 2 Department of Geology and Geophysics, University of Hawaii at Manoa, Honolulu, HI 96822, USA Received 2008 September 12; accepted 2009 May 29; published 2009 July 16 ABSTRACT We provide estimates of volcanism versus time for planets with Earth-like composition and masses 0.25–25 M⊕, as a step toward predicting atmospheric mass on extrasolar rocky planets. Volcanism requires melting of the silicate mantle. We use a thermal evolution model, calibrated against Earth, in combination with standard melting models, to explore the dependence of convection-driven decompression mantle melting on planet mass. We show that (1) volcanism is likely to proceed on massive planets with plate tectonics over the main-sequence lifetime of the parent star; (2) crustal thickness (and melting rate normalized to planet mass) is weakly dependent on planet mass; (3) stagnant lid planets live fast (they have higher rates of melting than their plate tectonic counterparts early in their thermal evolution), but die young (melting shuts down after a few Gyr); (4) plate tectonics may not operate on high-mass planets because of the production of buoyant crust which is difficult to subduct; and (5) melting is necessary but insufficient for efficient volcanic degassing—volatiles partition into the earliest, deepest melts, which may be denser than the residue and sink to the base of the mantle on young, massive planets. -
Geological Evolution of the Red Sea: Historical Background, Review and Synthesis
See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/277310102 Geological Evolution of the Red Sea: Historical Background, Review and Synthesis Chapter · January 2015 DOI: 10.1007/978-3-662-45201-1_3 CITATIONS READS 6 911 1 author: William Bosworth Apache Egypt Companies 70 PUBLICATIONS 2,954 CITATIONS SEE PROFILE Some of the authors of this publication are also working on these related projects: Near and Middle East and Eastern Africa: Tectonics, geodynamics, satellite gravimetry, magnetic (airborne and satellite), paleomagnetic reconstructions, thermics, seismics, seismology, 3D gravity- magnetic field modeling, GPS, different transformations and filtering, advanced integrated examination. View project Neotectonics of the Red Sea rift system View project All content following this page was uploaded by William Bosworth on 28 May 2015. The user has requested enhancement of the downloaded file. All in-text references underlined in blue are added to the original document and are linked to publications on ResearchGate, letting you access and read them immediately. Geological Evolution of the Red Sea: Historical Background, Review, and Synthesis William Bosworth Abstract The Red Sea is part of an extensive rift system that includes from south to north the oceanic Sheba Ridge, the Gulf of Aden, the Afar region, the Red Sea, the Gulf of Aqaba, the Gulf of Suez, and the Cairo basalt province. Historical interest in this area has stemmed from many causes with diverse objectives, but it is best known as a potential model for how continental lithosphere first ruptures and then evolves to oceanic spreading, a key segment of the Wilson cycle and plate tectonics. -
Coordinate Systems in Geodesy
COORDINATE SYSTEMS IN GEODESY E. J. KRAKIWSKY D. E. WELLS May 1971 TECHNICALLECTURE NOTES REPORT NO.NO. 21716 COORDINATE SYSTElVIS IN GEODESY E.J. Krakiwsky D.E. \Vells Department of Geodesy and Geomatics Engineering University of New Brunswick P.O. Box 4400 Fredericton, N .B. Canada E3B 5A3 May 1971 Latest Reprinting January 1998 PREFACE In order to make our extensive series of lecture notes more readily available, we have scanned the old master copies and produced electronic versions in Portable Document Format. The quality of the images varies depending on the quality of the originals. The images have not been converted to searchable text. TABLE OF CONTENTS page LIST OF ILLUSTRATIONS iv LIST OF TABLES . vi l. INTRODUCTION l 1.1 Poles~ Planes and -~es 4 1.2 Universal and Sidereal Time 6 1.3 Coordinate Systems in Geodesy . 7 2. TERRESTRIAL COORDINATE SYSTEMS 9 2.1 Terrestrial Geocentric Systems • . 9 2.1.1 Polar Motion and Irregular Rotation of the Earth • . • • . • • • • . 10 2.1.2 Average and Instantaneous Terrestrial Systems • 12 2.1. 3 Geodetic Systems • • • • • • • • • • . 1 17 2.2 Relationship between Cartesian and Curvilinear Coordinates • • • • • • • . • • 19 2.2.1 Cartesian and Curvilinear Coordinates of a Point on the Reference Ellipsoid • • • • • 19 2.2.2 The Position Vector in Terms of the Geodetic Latitude • • • • • • • • • • • • • • • • • • • 22 2.2.3 Th~ Position Vector in Terms of the Geocentric and Reduced Latitudes . • • • • • • • • • • • 27 2.2.4 Relationships between Geodetic, Geocentric and Reduced Latitudes • . • • • • • • • • • • 28 2.2.5 The Position Vector of a Point Above the Reference Ellipsoid . • • . • • • • • • . .• 28 2.2.6 Transformation from Average Terrestrial Cartesian to Geodetic Coordinates • 31 2.3 Geodetic Datums 33 2.3.1 Datum Position Parameters . -
The Way the Earth Works: Plate Tectonics
CHAPTER 2 The Way the Earth Works: Plate Tectonics Marshak_ch02_034-069hr.indd 34 9/18/12 2:58 PM Chapter Objectives By the end of this chapter you should know . > Wegener's evidence for continental drift. > how study of paleomagnetism proves that continents move. > how sea-floor spreading works, and how geologists can prove that it takes place. > that the Earth’s lithosphere is divided into about 20 plates that move relative to one another. > the three kinds of plate boundaries and the basis for recognizing them. > how fast plates move, and how we can measure the rate of movement. We are like a judge confronted by a defendant who declines to answer, and we must determine the truth from the circumstantial evidence. —Alfred Wegener (German scientist, 1880–1930; on the challenge of studying the Earth) 2.1 Introduction In September 1930, fifteen explorers led by a German meteo- rologist, Alfred Wegener, set out across the endless snowfields of Greenland to resupply two weather observers stranded at a remote camp. The observers had been planning to spend the long polar night recording wind speeds and temperatures on Greenland’s polar plateau. At the time, Wegener was well known, not only to researchers studying climate but also to geologists. Some fifteen years earlier, he had published a small book, The Origin of the Con- tinents and Oceans, in which he had dared to challenge geologists’ long-held assumption that the continents had remained fixed in position through all of Earth history. Wegener thought, instead, that the continents once fit together like pieces of a giant jigsaw puzzle, to make one vast supercontinent. -
MAGNITUDE of DRIVING FORCES of PLATE MOTION Since the Plate
J. Phys. Earth, 33, 369-389, 1985 THE MAGNITUDE OF DRIVING FORCES OF PLATE MOTION Shoji SEKIGUCHI Disaster Prevention Research Institute, Kyoto University, Uji, Kyoto, Japan (Received February 22, 1985; Revised July 25, 1985) The absolute magnitudes of a variety of driving forces that could contribute to the plate motion are evaluated, on the condition that all lithospheric plates are in dynamic equilibrium. The method adopted here is to solve the equations of torque balance of these forces for all plates, after having estimated the magnitudes of the ridge push and slab pull forces from known quantities. The former has been estimated from the age of ocean floors, the depth and thickness of oceanic plates and hence lateral density variations, and the latter from the density con- trast between the downgoing slab and the surrounding mantle, and the thickness and length of the slab. The results from the present calculations show that the magnitude of the slab pull forces is about five times larger than that of the ridge push forces, while the North American and South American plates, which have short and shallow slabs but long oceanic ridges, appear to be driven by the ridge push force. The magnitude of the slab pull force exerted on the Pacific plate exceeds to 40 % of the total slab pull forces, and that of the ridge push force working on the Pacific plate is the largest among the ridge push forces exerted on the plates. The high cor- relation that exists between the mantle drag force and the sum of the slab pull and ridge push forces makes it difficult to evaluate the absolute net driving forces. -
Journal of Geodynamics the Interdisciplinary Role of Space
Journal of Geodynamics 49 (2010) 112–115 Contents lists available at ScienceDirect Journal of Geodynamics journal homepage: http://www.elsevier.com/locate/jog The interdisciplinary role of space geodesy—Revisited Reiner Rummel Institute of Astronomical and Physical Geodesy (IAPG), Technische Universität München, Arcisstr. 21, 80290 München, Germany article info abstract Article history: In 1988 the interdisciplinary role of space geodesy has been discussed by a prominent group of leaders in Received 26 January 2009 the fields of geodesy and geophysics at an international workshop in Erice (Mueller and Zerbini, 1989). Received in revised form 4 August 2009 The workshop may be viewed as the starting point of a new era of geodesy as a discipline of Earth Accepted 6 October 2009 sciences. Since then enormous progress has been made in geodesy in terms of satellite and sensor systems, observation techniques, data processing, modelling and interpretation. The establishment of a Global Geodetic Observing System (GGOS) which is currently underway is a milestone in this respect. Wegener Keywords: served as an important role model for the definition of GGOS. In turn, Wegener will benefit from becoming Geodesy Satellite geodesy a regional entity of GGOS. −9 Global observing system What are the great challenges of the realisation of a 10 global integrated observing system? Geodesy Global Geodetic Observing System is potentially able to provide – in the narrow sense of the words – “metric and weight” to global studies of geo-processes. It certainly can meet this expectation if a number of fundamental challenges, related to issues such as the international embedding of GGOS, the realisation of further satellite missions and some open scientific questions can be solved. -
An Evidence-Based Approach to Teaching Plate Tectonics in High School
An evidence-based approach to teaching plate tectonics in high school COLIN PRICE ABSTRACT 5. relating the extreme age and stability of a large part of the Australian continent to its plate tectonic This article proposes an evidence-based and engaging history. approach to teaching the mechanisms driving the movement of tectonic plates that should lead high The problem with this list is the fourth elaboration, school students towards the prevalent theories because the idea that convection currents in the used in peer-reviewed science journals and taught mantle drive the movement of tectonic plates is a in universities. The methods presented replace the myth. This convection is presented as whole mantle inaccurate and outdated focus on mantle convection as or whole asthenosphere cells with hot material rising the driving mechanism for plate motion. Students frst under the Earth’s divergent plate boundaries and examine the relationship between the percentages of cooler material sinking at the convergent boundaries plate boundary types of the 14 largest plates with their with the lithosphere dragged along by the horizontal GPS-determined plate speeds to then evaluate the fow of the asthenosphere (Figure 1). This was the three possible driving mechanisms: mantle convection, preferred explanation for plate motion until the ridge push and slab pull. A classroom experiment early 1990s but it does not stand up to a frequent measuring the densities of igneous and metamorphic deduction made by Year 9 students: how can there be rocks associated with subduction zones then provides large-scale mantle convection if hotspots (like Hawaii) a plausible explanation for slab pull as the dominant don’t move? Most science teachers quickly cover driving mechanism. -
Sunsets, Tall Buildings, and the Earth's Radius
Sunsets, tall buildings, and the Earth’s radius P.K.Aravind Physics Department Worcester Polytechnic Institute Worcester, MA 01609 ([email protected] ) ABSTRACT It is shown how repeated observations of the sunset from various points up a tall building can be used to determine the Earth’s radius. The same observations can also be used, at some latitudes, to deduce an approximate value for the amount of atmospheric refraction at the horizon. Eratosthenes appears to have been the first to have determined the Earth’s radius by measuring the altitude of the sun at noon in Alexandria on a day when he knew it to be directly overhead in Syene (Aswan) to the south [1]. Despite the vastly better methods of determining the Earth’s size and shape today, Eratosthenes’ achievement continues to inspire schoolteachers and their students around the world. I can still recall my high school principal, Mr. Jack Gibson, telling us the story of Eratosthenes on numerous occasions in his inimitable style, which required frequent audience participation from the schoolboys gathered around him. In 2005, as part of the celebrations accompanying the World Year of Physics, the American Physical Society organized a project [2] in which students from 700 high schools all over North America collaborated in a recreation of Eratosthenes’ historic experiment. The schools were teamed up in pairs, and each pair carried out measurements similar to those of Eratosthenes and pooled their results to obtain a value for the Earth’s radius. The average of all the results so obtained yielded a value for the Earth’s radius that differed from the true value by just 6%. -
The Relation Between Mantle Dynamics and Plate Tectonics
The History and Dynamics of Global Plate Motions, GEOPHYSICAL MONOGRAPH 121, M. Richards, R. Gordon and R. van der Hilst, eds., American Geophysical Union, pp5–46, 2000 The Relation Between Mantle Dynamics and Plate Tectonics: A Primer David Bercovici , Yanick Ricard Laboratoire des Sciences de la Terre, Ecole Normale Superieure´ de Lyon, France Mark A. Richards Department of Geology and Geophysics, University of California, Berkeley Abstract. We present an overview of the relation between mantle dynam- ics and plate tectonics, adopting the perspective that the plates are the surface manifestation, i.e., the top thermal boundary layer, of mantle convection. We review how simple convection pertains to plate formation, regarding the aspect ratio of convection cells; the forces that drive convection; and how internal heating and temperature-dependent viscosity affect convection. We examine how well basic convection explains plate tectonics, arguing that basic plate forces, slab pull and ridge push, are convective forces; that sea-floor struc- ture is characteristic of thermal boundary layers; that slab-like downwellings are common in simple convective flow; and that slab and plume fluxes agree with models of internally heated convection. Temperature-dependent vis- cosity, or an internal resistive boundary (e.g., a viscosity jump and/or phase transition at 660km depth) can also lead to large, plate sized convection cells. Finally, we survey the aspects of plate tectonics that are poorly explained by simple convection theory, and the progress being made in accounting for them. We examine non-convective plate forces; dynamic topography; the deviations of seafloor structure from that of a thermal boundary layer; and abrupt plate- motion changes.