An inverted continental Moho and serpentinization of the forearc mantle M.G. Bostock, R.D. Hyndman, S. Rondenay, and S.M. Peacock Presented by: Lauren.

Slides:

Advertisements

Similar presentations

Cascadia Ken Creager, Steve Malone, Geoff Abers, Stephane Rondenay, Brad Hacker and Tim Melbourne Earth and Space Sciences University of Washington.

Advertisements

Slab-mantle decoupling and its implications for subduction zone thermal structure, fluid supply, and geophysical processes Ikuko Wada1,2 and Kelin Wang1,2.

Lithospheric Plates The lithosphere can be defined thermally by an isotherm at the base of the lithosphere which should be around 1350 o C. Mantle rocks.

Conclusions… Challenge: 1)Seismic waves are affected by variations in temperature, pressure, composition, mineralogy, structure (layering, scales and distribution.

The Earth’s Structure Seismology and the Earth’s Deep Interior The Earth’s Structure from Travel Times Spherically symmetric structure: PREM - Crustal.

Earth’s Interior and Geophysical Properties Chapter 17.

The Dynamic Crust Regents Earth Science. Seismic Waves and Earth’s Structure How can we tell that the outer core is liquid and the inner core is solid?

Lecture Outlines Physical Geology, 14/e Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Plummer, Carlson &

Planet Earth in Profile The Layered Interior. Objectives Explore evidence that helps explain Earth’s internal structure. Outline Earth’s internal layers.

GEO 5/6690 Geodynamics 12 Nov 2014 © A.R. Lowry 2014 Read for Fri 14 Nov: T&S Last Time: Te and Rheology Key point of Willett et al. papers: T.

Lessons we have learned from seismological observations in the Taiwan region Jer-Ming Chiu CERI/Dept. of Earth Sciences University of Memphis March 19,

Predicting Global Perovskite to Post-Perovskite Phase Boundary Don Helmberger, Daoyuan Sun, Xiaodong Song, Steve Grand, Sidio Ni, and Mike Gurnis.

Seismological Tests (and Implications) of Post-Perovskite Presence in the Deep Mantle In collaboration with Ed Garnero, Alex Hutko John Hernlund In collaboration.

Geology of the Lithosphere 2. Evidence for the Structure of the Crust & Upper Mantle What is the lithosphere and what is the structure of the lithosphere?

Global Distribution of Crustal Material Inferred by Seismology Nozomu Takeuchi (ERI, Univ of Tokyo) (1)Importance of Directional Measurements from geophysicists’

Seismic Profiles of Earth’s Interior

Thermal structure of old continental lithosphere from the inversion of surface-wave dispersion with thermodynamic a-priori constraints N. Shapiro, M. Ritzwoller,

Three Worlds to Explore Look Up? (Astronomy) Look Down? (Geophysics) Look at Surface? (Geology)

GG 450 April 15, 2008 Refraction Applications. While refraction is used for engineering studies such as depth to basement and depth to the water table,

Many Collaborators: Vadim Levin (Rutgers) Nikolai Shapiro (Univ Colorado) Michael Ritzwoller (Univ Colorado) Evgenii Gordeev (EMSD, Petropavlovsk) Jonathan.

A low velocity layer (LVZ) at the top of the subducting plate has been detected in a majority of subduction zones. LVZ may be a hydrated layer of oceanic.

EARTHQUAKES. Causes Sudden release of energy stored in rocks –Released as seismic waves Elastic Rebound Theory –Fault motion –Tectonic forces Also associated.

Locating Earthquakes Earthquake occurs when there is a rupture in the rock or when the strain builds up enough to cause movement along a fault. 3 waves.

13. Subduction Zones William Wilcock

Journey to the Center of the Earth

Dealing with paradoxes in subduction zone geodynamics

Travel-time versus Distance Curves

Earthquakes and Earth’s Interior

GEO 5/6690 Geodynamics 01 Dec 2014 © A.R. Lowry 2014 Read for Wed 3 Dec: T&S Last Times: Plate as Lithosphere; The Tectosphere Tectosphere is used.

Earth Structure.

GLOBAL TOPOGRAPHY. CONTINENTAL & OCEANIC LITHOSPHERE.

Seismological observations Earth’s deep interior, and their geodynamical and mineral physical interpretation Arwen Deuss, Jennifer Andrews University of.

Section 19.2– Seismic Waves and the Earth’s Interior

Water in the Mantle ? Can be stored: 1)Hydrous minerals - only stable shallow 2) Dissolved in normally anhydrous minerals 3)A hydrous silica-rich fluid.

Artifacts of teleseismic body- wave inversion Don L. Anderson.

Global seismic tomography and its CIDER applications Adam M. Dziewonski KITP, July 14, 2008.

Upper Mantle Seismic Anisotropy around the Plate Edge beneath northern Taiwan Wen-Tzong Liang 1 Yih-Zhen Hsu 2 Bor-Shouh Huang 1 Char-Shine Liu 3 1.Institute.

Earthquakes and the Interior  Earthquakes are definitely a geologic hazard for people living in earthquake regions, but the seismic waves generated by.

Seismological studies on mantle upwelling in NE Japan: Implications for the genesis of arc magmas Junichi Nakajima & Akira Hasegawa Research Center for.

Lithospheric Structure of the Gulf of California – Salton Trough Region, NARS-Baja Array Working Group: Robert Clayton, Caltech Don Forsyth, Brown Antonio.

IRIS Summer Intern Training Course Wednesday, May 31, 2006 Anne Sheehan Lecture 3: Teleseismic Receiver functions Teleseisms Earth response, convolution.

Other Tectonic Rifts: the Woodlark-D'Entrecasteaux Rift, Papua New Guinea Geoffrey Abers, Boston University Thanks to: A. Ferris (BU), S. Baldwin (Syracuse),

There are Mantle Plumes originating from the CMB!.

Recognizing Reflected Tremor Phases: Guidance from Synthetic Seismograms Amanda Klaus ESS 522 – Geophysical Data Analysis Final Project June 10, 2010.

Glenn Spinelli Effects of fluid circulation in ocean crust on subduction zone temperatures and metamorphism.

The crust and the Earth’s interior

Plate tectonics II: Earth’s structure and plate boundaries

Chapter 12: Earth’s Interior

Attenuation and Anelasticity

1 Wavefield Calibration Using Regional Network Data R. B. Herrmann Saint Louis University.

EXPLORING EARTH’S INTERIOR Chapter 14. Seismic rays are refracted away from the normal as they penetrate the earth, which causes them to bend, because.

The Earth’s Interior. Most of what we know is from geophysics.

Earth’s Internal Processes

The nature of the fore arc mantle and implications for seismic anisotropy Peter van Keken University of Michigan With: Erik Kneller, Shun Karato, Ikuo.

Seismogenic Characteristics and Seismic Structure of the Mariana Arc: Comparison with Central America Douglas A. Wiens, James Conder, Sara Pozgay, Mitchell.

Seismic waves Mathilde B. Sørensen and Jens Havskov.

TEMPERATURE  The deeper you go, the hotter it gets. & Celsius 4,000° C 4,000 km 2,000 km & kilometers 5,000° C 6,000 km F F mi.

Geology 5670/6670 Inverse Theory 20 Mar 2015 © A.R. Lowry 2015 Last time: Cooperative/Joint Inversion Cooperative or Joint Inversion uses two different.

Lecture Outlines Physical Geology, 12/e Plummer & Carlson Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

GEO 5/6690 Geodynamics 03 Dec 2014 © A.R. Lowry 2014 Read for Fri 5 Dec: T&S Last Time: Buoyancy (Tectosphere) vs Rheology The isopycnic hypothesis.

Thermal and Metamorphic Environment of Subduction-Zone Episodic Tremor and Slip Simon M. Peacock Dept. of Earth and Ocean Sciences University of British.

What is the thermal structure of a subduction zone?

GyPSM: Geodynamic and Petrological Synthesis Model Example: The northern Izu-Bonin segment of the IBM arc system subduction velocity: 5 cm/yr overriding.

Douglas A. Wiens & James Conder

Lithosphere Delamination and Small-Scale Convection Beneath California Imaged with High Resolution Rayleigh Wave Tomography Donald W. Forsyth and Yingjie.

Topic 3, Section 1: Elementary Plate Tectonics

Length scale of heterogeneity

Seismic tomography Tomography attempts to determine anomalous structures within the Earth as revealed by deviations from “average” seismic properties at.

How Laramide-Age Hydration of North American Lithosphere by the Farallon Slab Controlled Subsequent Activity in the Western United States Humphreys, Hessler,

Earthquakes track subduction fluids from slab source to mantle wedge sink by Felix Halpaap, Stéphane Rondenay, Alexander Perrin, Saskia Goes, Lars Ottemöller,

Presentation transcript:

An inverted continental Moho and serpentinization of the forearc mantle M.G. Bostock, R.D. Hyndman, S. Rondenay, and S.M. Peacock Presented by: Lauren Mattatall March 26, 2007

► To explore structure of the mantle wedge in the southern Cascadia subduction zone (CSZ) ► To understand the observed variations in velocity structure in the forearc region

► Relief map of the CSZ  White squares represent broadband stations ► Collected data from a dense broadband array of 69 stations across Central Oregon  high-quality P-wave seismograms from 31 events Bostock et al., 2002

Applied formal, multichannel inversions of: 1) Applied formal, multichannel inversions of: -forward scattered P to S wave conversions -back-scattered waves caused by free surface reflections 2) Plotted perturbations in velocity structure Bostock et al., 2002

3) Plotted a thermal model for Central Oregon -based on teleseismic profile, heat flow, and other geophysical data ► Note that the temperatures in the forearc are 400°-600° (200°-400° colder than arc temperatures)

► Sharp increase in dip angle (from ~10° to ~30°) argues for eclogitization of the slab ► Eclogitization implies hydration and serpentinization of the forearc ► Thermal model temperatures are within the range that serpentine minerals are thought to be stable ► With a high enough % composition, serpentinization of the forearc would significantly reduce S-wave velocities Bostock et al., 2002

► As presence of serpentinite increases, S-wave velocities decrease ► Observed S-wave velocities in the forearc indicate a possible composition of serpentinite as high as 50-60% Bostock et al., 2002

► Serpentine and it’s alteration products are though to exhibit stable sliding properties and will impede rupture into the forearc mantle ► Mantle flow into the wedge may be modified by the presence of the serpentinized forearc mantle  The weak rheology and positive buoyancy will cause isolation from the mantle-wedge corner flow system

► To what depth are the perturbation plots reliable? ► Are there other possible explanations for such a decreased velocity within the forearc?