Tides As Drivers of Plates and Criticism of Mantle Convection
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The Double Tidal Bulge
The Double Tidal Bulge If you look at any explanation of tides the force is indeed real. Try driving same for all points on the Earth. Try you will see a diagram that looks fast around a tight bend and tell me this analogy: take something round something like fig.1 which shows the you can’t feel a force pushing you to like a roll of sticky tape, put it on the tides represented as two bulges of the side. You are in the rotating desk and move it in small circles (not water – one directly under the Moon frame of reference hence the force rotating it, just moving the whole and another on the opposite side of can be felt. thing it in a circular manner). You will the Earth. Most people appreciate see that every point on the object that tides are caused by gravitational 3. In the discussion about what moves in a circle of equal radius and forces and so can understand the causes the two bulges of water you the same speed. moon-side bulge; however the must completely ignore the rotation second bulge is often a cause of of the Earth on its axis (the 24 hr Now let’s look at the gravitation pull confusion. This article attempts to daily rotation). Any talk of rotation experienced by objects on the Earth explain why there are two bulges. refers to the 27.3 day rotation of the due to the Moon. The magnitude and Earth and Moon about their common direction of this force will be different centre of mass. -
Geology of Hawaii Reefs
11 Geology of Hawaii Reefs Charles H. Fletcher, Chris Bochicchio, Chris L. Conger, Mary S. Engels, Eden J. Feirstein, Neil Frazer, Craig R. Glenn, Richard W. Grigg, Eric E. Grossman, Jodi N. Harney, Ebitari Isoun, Colin V. Murray-Wallace, John J. Rooney, Ken H. Rubin, Clark E. Sherman, and Sean Vitousek 11.1 Geologic Framework The eight main islands in the state: Hawaii, Maui, Kahoolawe , Lanai , Molokai , Oahu , Kauai , of the Hawaii Islands and Niihau , make up 99% of the land area of the Hawaii Archipelago. The remainder comprises 11.1.1 Introduction 124 small volcanic and carbonate islets offshore The Hawaii hot spot lies in the mantle under, or of the main islands, and to the northwest. Each just to the south of, the Big Island of Hawaii. Two main island is the top of one or more massive active subaerial volcanoes and one active submarine shield volcanoes (named after their long low pro- volcano reveal its productivity. Centrally located on file like a warriors shield) extending thousands of the Pacific Plate, the hot spot is the source of the meters to the seafloor below. Mauna Kea , on the Hawaii Island Archipelago and its northern arm, the island of Hawaii, stands 4,200 m above sea level Emperor Seamount Chain (Fig. 11.1). and 9,450 m from seafloor to summit, taller than This system of high volcanic islands and asso- any other mountain on Earth from base to peak. ciated reefs, banks, atolls, sandy shoals, and Mauna Loa , the “long” mountain, is the most seamounts spans over 30° of latitude across the massive single topographic feature on the planet. -
Lecture Notes in Physical Oceanography
LECTURE NOTES IN PHYSICAL OCEANOGRAPHY ODD HENRIK SÆLEN EYVIND AAS 1976 2012 CONTENTS FOREWORD INTRODUCTION 1 EXTENT OF THE OCEANS AND THEIR DIVISIONS 1.1 Distribution of Water and Land..........................................................................1 1.2 Depth Measurements............................................................................................3 1.3 General Features of the Ocean Floor..................................................................5 2 CHEMICAL PROPERTIES OF SEAWATER 2.1 Chemical Composition..........................................................................................1 2.2 Gases in Seawater..................................................................................................4 3 PHYSICAL PROPERTIES OF SEAWATER 3.1 Density and Freezing Point...................................................................................1 3.2 Temperature..........................................................................................................3 3.3 Compressibility......................................................................................................5 3.4 Specific and Latent Heats.....................................................................................5 3.5 Light in the Sea......................................................................................................6 3.6 Sound in the Sea..................................................................................................11 4 INFLUENCE OF ATMOSPHERE ON THE SEA 4.1 Major Wind -
Chapter 5 Water Levels and Flow
253 CHAPTER 5 WATER LEVELS AND FLOW 1. INTRODUCTION The purpose of this chapter is to provide the hydrographer and technical reader the fundamental information required to understand and apply water levels, derived water level products and datums, and water currents to carry out field operations in support of hydrographic surveying and mapping activities. The hydrographer is concerned not only with the elevation of the sea surface, which is affected significantly by tides, but also with the elevation of lake and river surfaces, where tidal phenomena may have little effect. The term ‘tide’ is traditionally accepted and widely used by hydrographers in connection with the instrumentation used to measure the elevation of the water surface, though the term ‘water level’ would be more technically correct. The term ‘current’ similarly is accepted in many areas in connection with tidal currents; however water currents are greatly affected by much more than the tide producing forces. The term ‘flow’ is often used instead of currents. Tidal forces play such a significant role in completing most hydrographic surveys that tide producing forces and fundamental tidal variations are only described in general with appropriate technical references in this chapter. It is important for the hydrographer to understand why tide, water level and water current characteristics vary both over time and spatially so that they are taken fully into account for survey planning and operations which will lead to successful production of accurate surveys and charts. Because procedures and approaches to measuring and applying water levels, tides and currents vary depending upon the country, this chapter covers general principles using documented examples as appropriate for illustration. -
Another Clue for Fast Motion of the Hawaiian Hotspot 27 February 2018
Another clue for fast motion of the Hawaiian hotspot 27 February 2018 Northwest Pacific. But soon there was doubt over whether hotspots are truly stationary. The biggest contradiction was a striking bend of about 60 degrees in this volcanic chain, which originated 47 million years ago. "If you try to explain this bend with just a sudden change in the movement of the Pacific Plate, you would expect a significantly different direction of motion at that time relative to adjacent tectonic plates," says Bernhard Steinberger of the GFZ German Research Center for Geosciences. "But we have not found any evidence for that." Recent studies have suggested that apparently two processes were effective: On the one hand, the Pacific Plate has changed its direction of motion. On the other hand, the Hawaiian hotspot moved relatively quickly southward in the period from 60 to about 50 million years ago - and then stopped. If this hotspot motion is considered, only a smaller change of Pacific plate motions is needed to explain the volcano chain. Graph shows the dates of volcanoes of the three volcanic chains in the Pacific and their relative movement over time (left). The location of the three This hypothesis is now supported by work in which volcanic chains shown in the map (right). The stars mark Steinberger is also involved. First author Kevin the youngest end or the active volcanoes today. Credit: Konrad, Oregon State University in Corvallis, Nature Communications, Kevin Konrad et al. Oregon, and his team have evaluated new rock dating of volcanoes in the Rurutu volcanic chain, including, for example, the Tuvalu volcanic islands in the Western Pacific. -
Tides and the Climate: Some Speculations
FEBRUARY 2007 MUNK AND BILLS 135 Tides and the Climate: Some Speculations WALTER MUNK Scripps Institution of Oceanography, La Jolla, California BRUCE BILLS Scripps Institution of Oceanography, La Jolla, California, and NASA Goddard Space Flight Center, Greenbelt, Maryland (Manuscript received 18 May 2005, in final form 12 January 2006) ABSTRACT The important role of tides in the mixing of the pelagic oceans has been established by recent experiments and analyses. The tide potential is modulated by long-period orbital modulations. Previously, Loder and Garrett found evidence for the 18.6-yr lunar nodal cycle in the sea surface temperatures of shallow seas. In this paper, the possible role of the 41 000-yr variation of the obliquity of the ecliptic is considered. The obliquity modulation of tidal mixing by a few percent and the associated modulation in the meridional overturning circulation (MOC) may play a role comparable to the obliquity modulation of the incoming solar radiation (insolation), a cornerstone of the Milankovic´ theory of ice ages. This speculation involves even more than the usual number of uncertainties found in climate speculations. 1. Introduction et al. 2000). The Hawaii Ocean-Mixing Experiment (HOME), a major experiment along the Hawaiian Is- An early association of tides and climate was based land chain dedicated to tidal mixing, confirmed an en- on energetics. Cold, dense water formed in the North hanced mixing at spring tides and quantified the scat- Atlantic would fill up the global oceans in a few thou- tering of tidal energy from barotropic into baroclinic sand years were it not for downward mixing from the modes over suitable topography. -
Hawaii Hotspot (Crustal Plate Movement)
Earth Science Name: Dynamic Crust Laboratory # 13 Hawaii Hotspot (Crustal Plate Movement) Introduction: Plate tectonics has been an accepted theory since the 1960’s. According to this theory, the crust of the Earth is composed of plates that move over the asthenosphere. There are two basic types of plates: heavy, thin and dense oceanic plates, which are primarily composed of basalt; and thick, lighter continental plates, which are comprised of silicate rocks (granite). Movement of the Pacific plate over the Hawaiian Hot Spot: The idea behind plate tectonics is that the crustal plates are moving with respect to one another over geologic time. The rates of movement of crustal plates can be determined by using data from the plate margins along the mid-ocean ridges, or at regions known as “HOTSPOTS” where the distance and age can be measured. The Hawaiian Islands are volcanic islands that are produced as superheated molten material rises upward from deep within the mantle. As the molten material breaks through weak places in the crustal plate a new “island” will form. Hawaii Crustal Plate Lab.doc 10/6/2013 1 Procedures: 1. Using Map 1 on this page and the absolute dates of lava in bold black numbers that represent millions of years before the present. Calculate the age difference between the islands and enter the data in the table on page 3. When there is more than one age on an island use an average! 2. Make distance measurements between the “dots” of each circle using the scale on the diagram. 3. Convert the distance from kilometers to “land” or “real” centimeters (NOT cm on the map!) by multiplying the distance in KM by 100,000 (which is the number of cm in 1 km). -
Archimedean Proof of the Physical Impossibility of Earth Mantle Convection by J. Marvin Herndon Transdyne Corporation San Diego
Archimedean Proof of the Physical Impossibility of Earth Mantle Convection by J. Marvin Herndon Transdyne Corporation San Diego, CA 92131 USA [email protected] Abstract: Eight decades ago, Arthur Holmes introduced the idea of mantle convection as a mechanism for continental drift. Five decades ago, continental drift was modified to become plate tectonics theory, which included mantle convection as an absolutely critical component. Using the submarine design and operation concept of “neutral buoyancy”, which follows from Archimedes’ discoveries, the concept of mantle convection is proven to be incorrect, concomitantly refuting plate tectonics, refuting all mantle convection models, and refuting all models that depend upon mantle convection. 1 Introduction Discovering the true nature of continental displacement, its underlying mechanism, and its energy source are among the most fundamental geo-science challenges. The seeming continuity of geological structures and fossil life-forms on either side of the Atlantic Ocean and the apparent “fit’ of their opposing coastlines led Antonio Snider-Pellegrini to propose in 1858, as shown in Fig. 1, that the Americas were at one time connected to Europe and Africa and subsequently separated, opening the Atlantic Ocean (Snider-Pellegrini, 1858). Fig. 1 The opening of the Atlantic Ocean, reproduced from (Snider-Pellegrini, 1858). 1 Half a century later, Alfred Wegener promulgated a similar concept, with more detailed justification, that became known as “continental drift” (Wegener, 1912). Another half century later, continental drift theory was modified to become plate tectonics theory (Dietz, 1961;Hess, 1962;Le Pichon, 1968;Vine and Matthews, 1963). Any theory of continental displacement requires a physically realistic mechanism and an adequate energy source. -
A Survey on Tidal Analysis and Forecasting Methods
Science of Tsunami Hazards A SURVEY ON TIDAL ANALYSIS AND FORECASTING METHODS FOR TSUNAMI DETECTION Sergio Consoli(1),* European Commission Joint Research Centre, Institute for the Protection and Security of the Citizen, Via Enrico Fermi 2749, TP 680, 21027 Ispra (VA), Italy Diego Reforgiato Recupero National Research Council (CNR), Institute of Cognitive Sciences and Technologies, Via Gaifami 18 - 95028 Catania, Italy R2M Solution, Via Monte S. Agata 16, 95100 Catania, Italy. Vanni Zavarella European Commission Joint Research Centre, Institute for the Protection and Security of the Citizen, Via Enrico Fermi 2749, TP 680, 21027 Ispra (VA), Italy Submitted on December 2013 ABSTRACT Accurate analysis and forecasting of tidal level are very important tasks for human activities in oceanic and coastal areas. They can be crucial in catastrophic situations like occurrences of Tsunamis in order to provide a rapid alerting to the human population involved and to save lives. Conventional tidal forecasting methods are based on harmonic analysis using the least squares method to determine harmonic parameters. However, a large number of parameters and long-term measured data are required for precise tidal level predictions with harmonic analysis. Furthermore, traditional harmonic methods rely on models based on the analysis of astronomical components and they can be inadequate when the contribution of non-astronomical components, such as the weather, is significant. Other alternative approaches have been developed in the literature in order to deal with these situations and provide predictions with the desired accuracy, with respect also to the length of the available tidal record. These methods include standard high or band pass filtering techniques, although the relatively deterministic character and large amplitude of tidal signals make special techniques, like artificial neural networks and wavelets transform analysis methods, more effective. -
Hawaiian Hotspot
V51B-0546 (AGU Fall Meeting) High precision Pb, Sr, and Nd isotope geochemistry of alkalic early Kilauea magmas from the submarine Hilina bench region, and the nature of the Hilina/Kea mantle component J-I Kimura*, TW Sisson**, N Nakano*, ML Coombs**, PW Lipman** *Department of Geoscience, Shimane University **Volcano Hazard Team, USGS JAMSTEC Shinkai 6500 81 65 Emperor Seamounts 56 42 38 27 20 12 5 0 Ma Hawaii Islands Ready to go! Hawaiian Hotspot N ' 0 3 ° 9 Haleakala 1 Kea trend Kohala Loa 5t0r6 end Mauna Kea te eii 95 ol Hualalai Th l 504 na io sit Mauna Loa Kilauea an 509 Tr Papau 208 Hilina Seamont Loihi lic ka 209 Al 505 N 98 ' 207 0 0 508 ° 93 91 9 1 98 KAIKO 99 SHINKAI 02 KAIKO Loa-type tholeiite basalt 209 Transitional basalt 95 504 208 Alkalic basalt 91 508 0 50 km 155°00'W 154°30'W Fig. 1: Samples obtained by Shinkai 6500 and Kaiko dives in 1998-2002 10 T-Alk Mauna Kea 8 Kilauea Basanite Mauna Loa -K M Hilina (low-Si tholeiite) 6 Hilina (transitional) Hilina (alkali) Kea Hilina (basanite) 4 Loa Hilina (nephelinite) Papau (Loa type tholeiite) primary 2 Nep Basaltic Basalt andesite (a) 0 35 40 45 50 55 60 SiO2 Fig. 2: TAS classification and comparison of the early Kilauea lavas to representative lavas from Hawaii Big Island. Kea-type tholeiite through transitional, alkali, basanite to nephelinite lavas were collected from Hilina bench. Loa-type tholeiite from Papau seamount 100 (a) (b) (c) OIB OIB OIB M P / e l p 10 m a S E-MORB E-MORB E-MORB Loa type tholeiite Low Si tholeiite Transitional 1 f f r r r r r r r f d y r r d b b -
Equilibrium Model of Tides Highly Idealized, but Very Instructive, View of Tides
Tides Outline • Equilibrium Theory of Tides — diurnal, semidiurnal and mixed semidiurnal tides — spring and neap tides • Dynamic Theory of Tides — rotary tidal motion — larger tidal ranges in coastal versus open-ocean regions • Special Cases — Forcing ocean water into a narrow embayment — Tidal forcing that is in resonance with the tide wave Equilibrium Model of Tides Highly Idealized, but very instructive, View of Tides • Tide wave treated as a deep-water wave in equilibrium with lunar/solar forcing • No interference of tide wave propagation by continents Tidal Patterns for Various Locations 1 Looking Down on Top of the Earth The Earth’s Rotation Under the Tidal Bulge Produces the Rise moon and Fall of Tides over an Approximately 24h hour period Note: This is describing the ‘hypothetical’ condition of a 100% water planet Tidal Day = 24h + 50min It takes 50 minutes for the earth to rotate 12 degrees of longitude Earth & Moon Orbit Around Sun 2 R b a P Fa = Gravity Force on a small mass m at point a from the gravitational attraction between the small mass and the moon of mass M Fa = Centrifugal Force on a due to rotation about the center of mass of the two mass system using similar arguments The Main Point: Force at and point a and b are equal and opposite. It can be shown that the upward (normal the the earth’s surface) tidal force on a parcel of water produced by the moon’s gravitational attraction is small (1 part in 9 million) compared to the downward gravitation force on that parcel of water caused by earth’s on gravitational attraction. -
(2 Points Each) 1. the Velocity Of
GG 101, Spring 2006 Name_________________________ Exam 2, March 9, 2006 A. Fill in the blank (2 points each) 1. The velocity of an S-wave is ______lower_________ than the velocity of a P-wave. 2. What type of seismic wave is being recorded by the above diagram? A __P__ wave. 3. The most voluminous layer of Earth is the ___mantle_________. 4. The rigid layer of Earth which consists of the crust and uppermost mantle is called the __ lithosphere__________. 5. Which of the major subdivisions of Earth's interior is thought to be liquid? ____outer core________. 6. When the giant ice sheets in the northern hemisphere melted after the last ice age, the Earth's crust ____rebounded____ because a large weight was removed. Name _______________________________ GG 101 Exam 2 Page 2 7. The process described in question 6 is an example of ___isostasy____. 8. Earth's dense core is thought to consist predominantly of ____iron________. 9. The island of Hawaii experiences volcanism because it is located above a(n) ___hot spot_________. 10. The Himalaya Mountains were caused by ___collision__ between ___India__________ and Asia. 11. ___Folds____ are the most common ductile response to stress on rocks in the earth’s crust. 12. ___Faults___ are the most common brittle response to stress on rocks in the earth’s crust. 13. What types of faults are depicted in the cross section shown above? ___thrust_______ faults. Name _______________________________ GG 101 Exam 2 Page 3 14. The structure shown in the above diagram is a(n) ____anticline_____. 15. The name of a fold that occurs in an area of intense deformation where one limb of the fold has been tilted beyond the vertical is called a(n) ____overturned____ fold.