| CODE | PHY3215 | |||||||||
| TITLE | Earthquake Seismology | |||||||||
| UM LEVEL | 03 - Years 2, 3, 4 in Modular Undergraduate Course | |||||||||
| MQF LEVEL | 6 | |||||||||
| ECTS CREDITS | 4 | |||||||||
| DEPARTMENT | Geosciences | |||||||||
| DESCRIPTION | The main goals of the study-unit are to provide an overview of earthquake seismology as a tool for investigating the structure of the earth, understanding earthquake sources, as well as societal implications of earthquake phenomena. It will introduce undergraduate physics students to quantitative analysis in seismology, and prepare them for further study in solid earth geophysics and earth structure using seismograms and computer tools. Seismology is an interesting application of the core physics principles learnt during earlier parts of the Physics and Mathematics degree course, such as wave propagation, field theory, general properties of matter, linear algebra etc. Moreover, the study unit will contain a strong component of practical use of standard computational software in seismology, as well as simple programming tasks. The topics to be covered are: 1. Earthquake Seismology: historical development of seismology; internal structure of the earth; elastic deformation and stress tensors and their relationship, generalized Hooke’s law;Helmoltz’s Theorem; equations of motion and wave propagation in an elastic medium; wave surfaces, rays and their properties; ray propagation in spherical media; energy transport. Reflection and refraction of elastic waves at solid-solid and liquid-liquid interfaces; head waves; inhomogeneous & evanescent wavefronts and bounded waves; Development of solutions in terms of rays & Eikonal equation; body waves through the earth and travel time equations. Surface waves (Rayleigh and Love); surface wave dispersion. An introduction to the inverse problem in seismology. Determination of earth structure: seismic earthquake tomography. Joint hypocenter determination (JHD). 2.Seismometry: inertial pendulum systems; electromagnetic instruments and force-feedback instruments; digital global networks, regional networks and seismic arrays. 3.Seismic sources: faulting sources, elastostatics, double couple hypothesis, elastodynamics; description of the earthquake source in terms of seismic moment tensor; focal mechanisms and fault plane solutions. Earthquake kinematics and dynamics: one dimensional Haskell source model, source spectrum, stress drop and rupture velocity. Magnitude scales, seismic energy and magnitude. Aftershocks and fault area. Earthquake statistics. 4. Computational Seismology: Extensive use of computer programs in seismology for earthquake location, seismogram analysis, earthquake source study, seismic hazard assessment, characterization and modelling of local site effects. Study-unit Aims The study-unit aims to: - provide students with a fundamental theoretical knowledge of seismic wave propagation, and how this is used to obtain knowledge about the structure of the earth; - familiarise the students with observational seismology and the art of seismogram interpretation; - introduce the students to the science of seismometry, i.e. various types of seismic recording instruments as well as the state-of-the-art in regional and global digital seismic networking; - provide students with a fundamental and quantitative knowledge of the the mechanics of the earthquake source, its radiation pattern, its spectral characteristics, relations between earthquake source and earthquake magnitude, the meaning of the various magnitude scales; - provide students with hands-on experience in the use of the latest computational software applied to a variety of seismological problems such as location of earthquake epicentres and depths, statistical seismology, determination of Earth structure, seismic hazard analysis. Learning Outcomes 1. Knowledge & Understanding: By the end of the study-unit the student will be able to: - give a detailed account of the earth's internal structure; - explain the relationships between the earth's elastic properties, and the propagation of seismic waves in the Earth; - give a quantitative account of the various seismic waves and their propagation inside the earth, both in terms of plane wave theory as well as in terms of ray propagation through spherical media; - describe quantitatively the reflection and transmission of seismic waves at a specified boundary; - distinguish between body waves and surface waves , and explain the dispersive nature of surface waves; - explain how inverse theory is used in the determination of earth structure and earthquake hypocentre determination; - give an account of the available types of seismic recorder and modern systems of seismic networks and arrays; - give a quantitative description of the earthquake source in terms of faulting mechanism, the seismic moment tensor, near-field and far-fielrd radiation pattern, source spectrum and stress drop; - distinguish between, and explain the various magnitude scales and the conditions under which they are used; - give an account of the statistics of earthquake occurrence, including aftershock sequences; - set up necessary data sets and files for use in standard computational software; - use appropriate computer programs to solve basic problems in seismology and seismic hazard analysis. 2. Skills: By the end of the study-unit the student will be able to: - discuss various theories about Earth's physical systems, their applicability and limitations; - have enough theoretical understanding to approach problems analytically and efficiently; - use and interpret seismograms and other seismological data to provide explanations about earthquake sources and about seismic wave paths; - relate earthquake source mechanisms to particular geodynamic situations in different areas; - interpret seismicity, seismotectonic , seismic hazard and seismic risk maps; - use various computer programs and packages to solve practical seimological problems, and process numerical data; - carry out some computer programming. Main Text/s and any supplementary readings Main Texts Lay and Wallace, 1995. Modern Global Seismology. Academic Press Stein and Wysession, 2002, An Introduction to Seismology, Earthquakes and Earth Structure, Blackwell Publishing Shearer, 2009, Introduction to Seismology, Cambridge University Press Supplementary Texts Aki and Richards, 2009, Quantitative Seismology, University Science Books Geldart and Sheriff , 2004, Problems in Exploration Seismology and Their Solutions, Geophysical References Udias, 2000. Principles of Seismology, Cambridge University Press Sholtz, 2007, The Mechanics of Earthquakes and Faulting (2nd Edition), Cambridge University Press |
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| ADDITIONAL NOTES | Pre-Requisites: Good Mathematical background Pre-Requisite Study-unit: PHY2130 |
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| STUDY-UNIT TYPE | Lecture and Tutorial | |||||||||
| METHOD OF ASSESSMENT |
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| LECTURER/S | Sebastiano D'Amico Pauline Galea (Co-ord.) |
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The University makes every effort to ensure that the published Courses Plans, Programmes of Study and Study-Unit information are complete and up-to-date at the time of publication. The University reserves the right to make changes in case errors are detected after publication.
The availability of optional units may be subject to timetabling constraints. Units not attracting a sufficient number of registrations may be withdrawn without notice. It should be noted that all the information in the description above applies to study-units available during the academic year 2023/4. It may be subject to change in subsequent years. |
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