# Geology for Engineers Earthquakes

Save this PDF as:

Size: px
Start display at page:

## Transcription

1 Geology for Engineers Earthquakes Name I. Introduction The crust of the earth behaves in a brittle manner. Stress is the force applied to a brittle substance and strain represents the build-up of energy in the brittle substance. As we apply stress to the crust strain increases in the rocks, and at some point the strain exceeds the strength of the rocks. When this occurs a fracture develops and the rocks move releasing some of the strain (stored energy). This released energy forms what we call an earthquake. A simple analogy may help you understand the above relationships. Take a wooded yard stick and bend it. The force you are exerting is the stress and the bending of the yard stick represents the build-up in strain (energy). If you bend the yard stick far enough it will break (i.e. it shows brittle behavior) releasing the builtup strain. We can sense this energy release since we will hear a snapping sound. The sound waves representing this snap were generated by the energy release. When an earthquake occurs waves propagate away from the source (hypocenter or focus) of the break. Waves which travel through the earth are called body waves and consist of two types: P waves which are longitudinal and S waves which are transverse. When the waves reach the surface another set of waves (L waves) develop which move along the earth's surface. The L waves are also transverse waves. The point on the surface directly above the source of the earthquake is referred to as the epicenter. Earthquake waves are sensed by a device called a seismograph. The arriving earthquake waves cause the device to vibrate and these vibrations are recorded on a moving strip chart. This record is referred to as a seismogram. The arrival times of the various waves yield information concerning the distance to the earthquake, and the amplitude of the trace on the strip chart is used to determine the magnitude of the earthquake. II. Energy and Earthquake Intensity and Magnitude Earthquakes are cataloged according to their magnitude or intensity. The earthquake magnitude is a measure of the energy released by an earthquake at the focus. The earthquake intensity scale is more subjective and assesses the effect of the earthquake at a particular location. Earthquake intensity. The most widely used intensity scale is the Modified Mercalli Intensity Scale (Table 1). Intensity is determined by the observed effects of earthquakes on structures. Since these effects are a function of not only the energy released by the earthquake but also the type of construction and the material on which the structures are built, the observed intensity for a particular earthquake can vary widely from location to location. For example, some years ago a large earthquake occurred just off Alcapulco. The observed damage in Alcapulco was minor, but Mexico City some 1OO's of kms away suffered significant damage. In part the much greater damage in Mexico City was due to the material on which the structures were built - old lake bed deposits. These materials are not well consolidated and tend to behave like a fluid during an earthquake. Thus there was differential movement of the subsurface which imputed stresses to buildings that exceeded the buildings' strength. Thus the design of earthquake resistant buildings requires 1

2 knowledge not only of the absolute energy that may be released by an earthquake but also knowledge of differential movements that might occur. Destruction of presumably earthquake proof structures during recent earthquakes is a sobering reminder of the limitations of engineered solutions to natural hazards. Table 1. Modified Mercalli Intensity scale Intensity I II III IV V VI VIII VII IX X XI XII Observed Effects Not felt except by a very few under especially favorable circumstances. Felt only by a few persons at rest, especially on upper floors of buildings. Delicately suspended objects may swing. Felt noticeably indoors, especially on upper floors of buildings, but many people do not recognize it as an earthquake. Standing automobiles may rock slightly. Vibration like a passing truck. During the day, felt indoors by many, outdoors by few. At night, some awakened. Dishes, windows, doors disturbed; walls make creaking sound. Sensation like heavy truck striking building. Standing automobiles rocked noticeably. Felt by nearly everyone, many awakened. Some dishes, windows, etc., broken; a few instances of cracked plaster; unstable objects overturned. Disturbances of trees, poles, and other tall objects sometimes noticed. Pendulum clocks may stop. Felt by all, many frightened and run outdoors. Some heavy furniture moved; a few instance of fallen plaster or damaged chimneys. Damage slight/ Everybody runs outdoors. Damage negligible in buildings of good design and construction; slight to moderate in well-build ordinary structures; considerable in poorly built or badly designed structures; some chimneys broken. Notice by persons driving automobiles. Damage slight in specially designed structures; considerable in ordinary substantial buildings with partial collapse; great in poorly built structures. Panel walls thrown out of frame structures. Fall of chimneys, factory stacks, columns, monuments, walls. Heavy furniture over-turned. Sand and mud ejected in small amounts. Changes in well water. Persons driving automobiles disturbed (road rage become rampant). Damage considerable in specially designed structures; well-designed frame structures thrown out of plumb; great damage in substantial buildings, with partial collapse. Buildings shifted off foundations. Ground cracked conspicuously. Some well-built wooden structures destroyed; most masonry and frame structures destroyed with foundations; ground badly cracked. Rails bent. Landslide considerable from riverbanks and steep slopes. Shifted sand and mud. Water splashed (slopped) over banks. Few, if any, (masonry) structures remain standing. Bridges destroyed. Broad fissures in ground. Underground pipelines completely out of service. Earth slumps and land slips in soft ground. Rails bent greatly. Damage total. Waves seen on ground surfaces. Lines of sight and level distorted. Objects thrown upward into air. 2

3 Earthquake magnitude. Earthquake magnitude is determined from the size of the trace on a standard seismograph. The standard earthquake is defined as one which will cause a 1 millimeter trace on a standard seismograph at a distance of 100 kilometers from the epicenter. The standard earthquake is assigned an arbitrary magnitude of 3. The magnitude is based on a logarithmic scale; that is, the number which indicates the magnitude is an exponent of 10. In order to calculate the magnitude of any earthquake based on the standard earthquake, whose magnitude is 3, it is necessary to know the distance between the recording station and the epicenter. The relationship between earthquake magnitude, distance and size of the seismograph trace is given by the nomogram (Figure 1). Figure 1. Nomogram for determining earthquake magnitudes from trace amplitudes in millimeters for a standard seismogram, based on a standard earthquake of magnitude 3 which causes a 1 mm trace on a standard seismograph 100 km distant from the epicenter. Corresponding values of Distance, Magnitude, and Amplitude lie on a straight line. 3

4 Earthquake energy. An earthquake occurs when there is a sudden release of energy. That portion of the energy that is recorded on a seismograph is due to wave motion. One obvious mechanism for the release of energy is faulting. In this case the total amount of released energy does mechanical work in moving masses of rock, generates heat as the result of friction and radiates various kinds of seismic waves. This last part of the energy released is that quantity of energy upon which the Richter magnitude scale is based. Once the magnitude of an earthquake is determined the amount of energy released as waves can be approximately computed from the following formula Log E = M (1) where E is the energy released and M is the Richter magnitude of the earthquake. This is an experimental formula, that is, it was derived from many observations and experiments and related theoretical calculations. Notice that the logarithm of the energy is used. This formula expresses the amount of energy released in the form of waves. In order to calculate the total energy released by an earthquake it is necessary to know the percent of the total energy that is released as waves. At the present time only crude estimates can be made for this factor. So besides the magnitude scale being somewhat approximate, the estimate of the total energy released is even more uncertain! The total amount of energy stored as strain in a given volume of rock is computed from the following formula E total = 0.5Ge 2 V (2) where G is the elastic modulus, e is the strain and V is the volume of rock in which the strain (energy) is stored. Energy (E total ) is expressed in ergs. One erg = one dyne-centimeter. Most calculations concerned with the study of the earth employ the cgs (centimeter-gram-second) or mks (meter-kilogram-second) metric systems of measure. The erg is the standard energy unit for the cgs system and the joule is the standard energy unit for the mks system. 1 joule = 1 x 10 7 ergs. The energy released by an earthquake is often compared to that released by a thermonuclear device ("the bomb"). By way of comparison, a 20 kiloton atom bomb releases approximately 8 x ergs of energy. 1. The Loma Pietra earthquake occurred at 5:04 PM on October 17, 1989, just before the start of the World Series game between the San Francisco Giants and the Oakland Athletics. The San Francisco Oakland Bay Bridge suffered severe damage and the Interstate 880/Cypress Viaduct collapsed. There was significant damage in San Francisco s marina district. A standard seismograph at Los Angeles, California recorded an amplitude trace of 140 millimeters. The distance to the epicenter, from Berkeley, was calculated as 500 kilometers. The average strain released in the region was 1.1 x 10-4 and the elastic modulus, G, is equal to 3 x dynes cm -2. a. Determine the Richter magnitude of the earthquake. Use the nomogram (Figure 1) to do this. 4

5 b. If the distance between Reno, Nevada and the epicenter is 400 kilometers, what should be the trace in millimeters at Reno? c. Using the formula (1) relating energy to magnitude, find the amount of energy (in ergs) released as waves by the earthquake. d. Assuming that only 50% of the total energy released was used in producing the waves, what would be the minimum total accumulated strain energy (= the total energy released) in the area just before the earthquake? e. The total energy released by the earthquake would be equivalent to how many 2O kiloton atomic bombs? f. Using the formula (2) for stored strain energy, compute the volume affected by the strain release in cubic kilometers (1 km 3 = cm 3 ). g. Assuming that the strain release extended to a depth of 15 kilometers, compute the area that was affected by the release of the strain energy. The volume is rectangular in shape and has a square crosssectional area. 5

6 III. Earthquake Waves That Travel Through the Earth With reference to Figure 2, let us assume that an earthquake occurs at #1. Seismograph stations A, B, C, D and E lie along a great circle route that will receive vibrations from the earthquake in sequence. From the nature of the motion, the seismologist knows that the waves have passed through the earth and not along its surface. As a first approximation let us assume that the waves have taken the paths shown in Figure 2. Figure 2. Travel paths for earthquake waves. The hypocenter (focus) is indicated by the x labeled #1. The velocity of the P-wave is 8 km s -1 and the velocity of the S-wave is 4.8 km s -1. Using the paths shown on Figure 2, compute the expected travel times for the P and S waves and enter these values in the appropriate place in Table 2. 6

7 Station Straight line distance from earthquake (km) Expected travel time (min) Observed travel time (min) P S P S A B C ND ND D 30.5 ND E 30.3 ND ND = earthquake wave not detected. 2. How do your calculated values compare with the observed values? Can you explain this? The speed at which waves travel through materials is related in the following ways: P-waves: (1) As the density of the medium increases the velocity increases. (2) As the incompressibility or resistance to change in volume increases the velocity increases. (3) As rigidity (a measure of resistance to change in shape) increases the velocity increases. S-waves: (1) As the density of the medium increases the velocity decreases. (2) As the rigidity increases the velocity increases. (3) The waves do not pass through material that behaves as a fluid. 3. What does the absence of the P and S waves at station C and the absence of the S waves at station D and E tell you about the structure of the earth. 7

8 IV. Location of an earthquake epicenter The record of an earthquake as recorded at four stations is shown in Figure 3. The first set of deflections marks the arrival of the P-waves. The second set of deflections marks the arrival of the S-waves. Figure 3. Arrival times for P- and S-waves from an earthquake. Indicated times are for the first arrival of the P-wave. Arrival time for the S-wave can be determined by measuring the distance between the first P-wave arrival and the first S-wave arrival and converting to time using the scale at the bottom of the figure. 4. Determine the lag in arrival time at each station. Enter the time lags in Table 3. 8

9 5. Assuming an average velocity of 6 km s -1 for the P-waves and 4 km s -1 for the S-waves how long does it take for each type of wave to travel 100 km? 6. What is the time lag at a distance of 1OO km? 7. Determine the distance from reach of the four seismograph stations to the epicenter of the earthquake. Distance may be computed by proportion using the time-lag value for 1OO kms determined above. Record the distances in Table 3. Table 3. Time-lags and distances between earthquake epicenter and seismograph stations. Station Los Angeles San Francisco Salt Lake City Albuquerque Distance between P S first arrivals (mm). Fig. 3 Time-lag (s) Distance from earthquake (km) 8. On the map (Figure 4) of the western United States draw arcs with centers at the four stations and with radii corresponding to the computed distances. Where is the epicenter located? 9. At what time did the earthquake actually occur? Refer back to the seismic records (Figure 3). 9

10 Figure 4. Map of the western United States showing the location of the seismograph stations. 10

### The Severity of an Earthquake - ---- U.S. Department of the Interior/Geological Survey

The Severity of an Earthquake - ---- U.S. Department of the Interior/Geological Survey ----~ Earthquakes can be measured in terms of either the effect of the earthquake (intensity) or of the energy released

### Name: Lab: Earthquake Epicenters Adapted from Exploration in Earth Science, The Physical Setting, United Publishing Company, Inc

Name: Lab: Earthquake Epicenters Adapted from Exploration in Earth Science, The Physical Setting, United Publishing Company, Inc INTRODUCTION: Earthquakes occur when there is movement along a fault. The

### Evaluating an Illinois Earthquake

Evaluating an Illinois Earthquake Grade Level: 7-8 Adapted from an activity by Robert A. Bauer, GeoActivity HAZD-1, ISGS GeoActivities Series, Activities and Other Resources for Teaching Geology, Illinois

1 of 37 http://www.youtube.com/watch?v=c0ya4_snbru 2 of 37 What are earthquakes? Earthquakes Earthquakes are vibrations caused by earth movements at plate boundaries and at major fault lines (cracks in

### Earthquakes Natural and Induced. Rick Aster Professor of Geophysics and Department Head Geosciences Department Colorado State University

Earthquakes Natural and Induced Rick Aster Professor of Geophysics and Department Head Geosciences Department Colorado State University Overview What causes earthquakes? How do we detect, locate, and measure

### Earthquakes and Volcanoes

Earthquakes and Volcanoes Earthquakes What are earthquakes? Imagine bending a stick until it breaks. When the stick snaps, it vibrates, releasing energy. Earthquakes release energy in a similar way. Earthquakes

### EARTHQUAKE MAGNITUDE

EARTHQUAKE MAGNITUDE Earliest measure of earthquake size Dimensionless number measured various ways, including M L local magnitude m b body wave magnitude M s surface wave magnitude M w moment magnitude

### EARTHQUAKES AND SEISMOLOGY

EARTHQUAKES AND SEISMOLOGY Seismology is the study of earthquakes and seismic waves. Seismologists are concern with minimizing earthquakes destructiveness. They do this by assessing seismic risk in different

### A Violent Pulse: Earthquakes

A Violent Pulse: Earthquakes What is an Earthquake? Earth shaking caused by a rapid release of energy. tectonic stress build up rock break. energy moves outward as an expanding sphere of waves. waveform

### Earthquakes and Volcanoes

chapter 38 Earthquakes and Volcanoes section 1 Earthquakes Before You Read Have you ever experienced an earthquake or perhaps seen an earthquake in a movie or on TV? On the lines below, describe an earthquake.

### Plotting Earthquakes LESSON

13 LESSON Plotting Earthquakes INTRODUCTION On September 19, 1985, a strong earthquake occurred in Mexico City. The quake killed more than 9000 people and destroyed thousands of buildings. Two months later,

### Seismic Waves Practice

1. Base your answer to the following question on the diagram below, which shows models of two types of earthquake waves. Model A best represents the motion of earthquake waves called 1) P-waves (compressional

### Earthquake History of North Carolina

Earthquake Education Workshops September 2014 Charlotte, Candler, and Winston-Salem, NC Earthquake History of North Carolina presented by Dr. Kenneth B. Taylor State Geologist Of North Carolina N.C. Geological

### 14. Print out the page that shows your Virtual Seismologist Certificate and ANSWERS 15. After getting all 4, turn it into the teacher.

The Process 1. Go to the website: http://www.sciencecourseware.org 2. Click on: GEOLOGY LABS ONLINE 3. Click on VIRTUAL EARTHQUAKE 4. NEXT click on: NEW: A completely revised version of Virtual Earthquake

### EARTHQUAKE. Definition of Hazard. History of Hazard as it Affects the City of Kent. Hazard Identification

EARTHQUAKE Definition of Hazard Earthquakes are defined as the sudden release of energy occurring from the collision or shifting of crustal plates on the earth s surface or from the fracture of stressed

### P-wave compression. propagating wave

Did you feel it? That side to side, up and down, ground-shaking motion felt by many Californians every year, not to mention folks all around the world. The shaking motion is referred to as an earthquake,

Earthquakes Table of Contents Section 1 What Are Earthquakes? Section 2 Earthquake Measurement Section 3 Earthquakes and Society http://youtu.be/lcvwan8w-jo http://youtu.be/xe7mfz8dnjw Section 1 What Are

### Chapter 6 Earthquakes

Chapter 6 Earthquakes by G.H. Girty, Department of Geological Sciences, San Diego State University Page 1 Introduction Earthquakes are a shaking and vibration of the land surface. Such a phenomenon commonly

### Earthquake: A vibration caused by the sudden breaking or frictional sliding of rock in the Earth. Fault: A fracture on which one body of rock slides

Earthquake: A vibration caused by the sudden breaking or frictional sliding of rock in the Earth. Fault: A fracture on which one body of rock slides past another. Focus: The location where a fault slips

### Sound Waves and Seismic Waves

Sound Waves and Seismic Waves Seismologists record and analyze waves to determine where an earthquake occurred and how large it was Waves are fundamental to music and seismology Similarities: More high

### How do scientists measure earthquakes?

Name: Source: http://www.scholastic.com/browse/article.jsp?id=4892 http://gizmodo.com/5833688/what-do-earthquake-magnitudes-mean http://www.kids-fun-science.com/moment-magnitude-scale.html http://tremor.nmt.edu/faq/how.html

### Shake, Rattle, and Roll. Tina Moore, Denise Robinette, & Matt Utz

Shake, Rattle, and Roll Tina Moore, Denise Robinette, & Matt Utz Shake, Rattle, and Roll - Earthquakes Lesson Plan - Day One I. Objective: A. Student will be able to read and label a two axis graph. B.

### Economic Benefit Cost Analysis: CoreFirst vs. Standard Retrofit

Economic Benefit Cost Analysis: CoreFirst vs. Standard Retrofit Kleinhenz & Associates 2602 Berkshire Road Cleveland, Ohio 44106 www.kleinhenzassociates.com June 2014 Introduction CoreFirst, llc. (CoreFirst)

### FOURTH GRADE EARTHQUAKES 1 WEEK LESSON PLANS AND ACTIVITIES

FOURTH GRADE EARTHQUAKES 1 WEEK LESSON PLANS AND ACTIVITIES PLATE TECTONIC CYCLE OVERVIEW OF FOURTH GRADE VOLCANOES WEEK 1. PRE: Comparing different structures of volcanoes. DURING: Modeling three types

### Seismic Earthquakes. The most common quakes occur from fault lines

Earthquakes GE 4150- Natural Hazards Slides and images taken from Dr. Jim Diehl, Jason R. Evans, Joanne M. Scott and Benfiled Greig Hazard Research Centre (C471 Geohazards) Tectonic Earthquakes Seismic

### Locating the Epicenter and Determining the Magnitude of an Earthquake

Locating the and Determining the Magnitude of an Earthquake Locating the Measuring the S-P time interval There are hundreds of seismic data recording stations throughout the United States and the rest

### EARTHQUAKES. Tommy Her, Ben Lee, James Edwards, Chandler Collier, Brent Dorn, and April Bartholomew (photographer)

EARTHQUAKES Tommy Her, Ben Lee, James Edwards, Chandler Collier, Brent Dorn, and April Bartholomew (photographer) Introduction to Physical Science, EMPACTS Project C. Dianne Phillips, Instructor, NWACC,

### EARTHQUAKES. Compressional Tensional Slip-strike

Earthquakes-page 1 EARTHQUAKES Earthquakes occur along faults, planes of weakness in the crustal rocks. Although earthquakes can occur anywhere, they are most likely along crustal plate boundaries, such

### Name: Date: Class: Finding Epicenters and Measuring Magnitudes Worksheet

Example Answers Name: Date: Class: Finding Epicenters and Measuring Magnitudes Worksheet Objective: To use seismic data and an interactive simulation to triangulate the location and measure the magnitude

### CHAPTER 4 EARTHQUAKES

CHAPTER 4 EARTHQUAKES Important Concepts 1. An earthquake occurs when movement along a fault zone results in a sudden release of built-up strain energy in the lithosphere. Most earthquakes occur at plate

### Earthquakes. www.earthquakes.bgs.ac.uk

Earthquakes www.earthquakes.bgs.ac.uk Introduction Earthquakes are among the most deadly natural hazards. There are around 100 earthquakes each year of a size that could cause serious damage. They strike

### Earthquakes. www.earthquakes.bgs.ac.uk. Seismograph stations operated by the British Geological Survey

Seismograph stations operated by the British Geological Survey Earthquakes Photograph supplied by Andy Thompson, Arup Advanced Technology, EEFIT Mission www.earthquakes.bgs.ac.uk Introduction Earthquakes

### Earthquake Risk in New Jersey

Earthquake Risk in New Jersey We felt a shock Was it an earthquake? NJ D E P Department of Environmental Protection Land Use Management New Jersey Geological Survey STATE OF NEW JERSEY Richard J. Codey,

### Questions & Answers Proposed for Exam #3

Questions & Answers Proposed for Exam #3 GE50 Introduction to Physical Geology (Geology for Engineers) Missouri University of Science and Technology Fall Semester 2007, Leslie Gertsch (GertschL@mst.edu)

### Chapter 7 Earthquake Hazards Practice Exam and Study Guide

Chapter 7 Earthquake Hazards Practice Exam and Study Guide 1. Select from the following list, all of the factors that affect the intensity of ground shaking. a. The magnitude of the earthquake b. Rather

### Unit 4 Lesson 6 Measuring Earthquake Waves. Copyright Houghton Mifflin Harcourt Publishing Company

Shake, Rattle, and Roll What happens during an earthquake? As plates of the lithosphere move, the stress on rocks at or near the edges of the plates increases. This stress causes faults to form. A fault

### Lecture 12 Earthquake Magnitude

Lecture 12 Earthquake Magnitude Locating Earthquakes Last time, we learned that we could obtain a rough estimate of the distance in miles to an earthquake epicenter by multiplying the S - P time interval

### The earthquake source

Global seismology: The earthquake source Reading: Fowler p111-140 and Bolt Appendix G Earthquake location Earthquake focus: Latitude, longitude, depth Earthquake epicenter: Latitude, longitude Earthquakes

### Name Date Class. By studying the Vocabulary and Notes listed for each section below, you can gain a better understanding of this chapter.

CHAPTER 7 VOCABULARY & NOTES WORKSHEET Earthquakes By studying the Vocabulary and Notes listed for each section below, you can gain a better understanding of this chapter. SECTION 1 Vocabulary In your

### NATURAL HAZARDS & NATURAL DISASTERS

NATURAL HAZARDS & NATURAL DISASTERS The World is always changing. Natural disasters are changes which are so great they may cause damage to the shape of the land or to the lives of people and other living

### NATURAL DISASTERS Vol. I - Earthquake Parameters Including Strong Earthquakes- S.L.Yunga EARTHQUAKE PARAMETERS INCLUDING STRONG EARTHQUAKES

EARTHQUAKE PARAMETERS INCLUDING STRONG EARTHQUAKES S.L.Yunga United Institute of physics of the Earth, Russian academy of sciences. B. Gruzinskaya,10, Moscow, 123810, Russia Keywords earthquake, epicenter,

### Unit 13: Earthquakes

Unit 13: Earthquakes A. Earthquakes 1. Earthquake vibration of Earth produced by the rapid release of energy 2. Focus The point within Earth where the earthquake starts 3. Epicenter Location on the surface

### Chapter 5: Earthquakes

Chapter 5: Earthquakes 1. Experiencing an Earthquake firsthand 2. The Science of Ghost Forests and Megaearthquakes 3. Faults, Earthquakes, and Plate Tectonics 4. Seismic Waves and Earthquake Detection

### DISASTER RESISTANCE EARTHQUAKES AND STRUCTURES

DISASTER RESISTANCE EARTHQUAKES AND STRUCTURES EARTHQUAKES Origin of earthquakes The earth was a single land about two hundred million years ago. This land split progressively over a long period of time

### Earthquakes. Earthquakes: Big Ideas. Earthquakes

Earthquakes Earthquakes: Big Ideas Humans cannot eliminate natural hazards but can engage in activities that reduce their impacts by identifying high-risk locations, improving construction methods, and

### Class Notes: Plate Tectonics

Name: Date: Period: Tectonics The Physical Setting: Earth Science Class Notes: Tectonics I. Continental Drift Continental Drift -! Pangaea -! Alfred Wegener (1915) German and Proposed the theory of! Hypothesized

### Earthquakes and the Earth s Interior

Earthquakes and the Earth s Interior San Francisco 1906 Magnitude 7.8 Charleston 1886 California s Notorious San Andreas Fault fault trace Earthquakes are the release of energy stored in rocks. Most earthquakes

### Earthquakes Natural and Induced

Earthquakes Natural and Induced Rick Aster Professor of Geophysics and Department Head Geosciences Department, Warner College of Natural Resources, Colorado State University with thanks to Randi Jean Walters

### sin ( sin(45 )) 70.5

Seismology and Global Waves Chap. 4 HW Answers 1. A swinging door is embedded in a N S oriented wall. What force direction would be required to make the door swing on its hinge?. A ray is travelling in

### The first wave to reach the surface in an earthquake is the primary

4 The first wave to reach the surface in an earthquake is the primary wave (P-wave), which is a type of compression or longitudinal wave. A longitudinal wave is one that transfers energy through compressions

### Seismic Waves. Epicenter and Focus. Focus. The shaking occurs as the energy travels out. form of waves (like ripples in water). Epicenter.

Seismic Waves When there is movement at a fault, energy is released: The shaking occurs as the energy travels out from the focus in the form of waves (like ripples in water). Epicenter and Fault Line Epicenter

### Earthquakes in Hawaii:

Earthquakes in Hawaii: What you need to know U.S. Department of the Interior U.S. Geological Survey Prepared by: Janet L. Babb Hawaiian Volcano Observatory Hawaii Standard Time The State of Hawaii experiences

### Chapter 9 Earthquakes and Volcanism

Chapter 9 Earthquakes and Volcanism I. Earth s Surface Relief II. Orogenesis III. Earthquakes A. What is an earthquake B. Anatomy of an Earthquake C. Measuring Earthquakes D. Tsunamis Earth s Hypsometry

### Earthquakes and Seismic Waves (pages 51 57)

Earthquakes and Seismic Waves (pages 51 57) Types of Seismic Waves (pages 52 53) Key Concept: Seismic waves carry energy from an earthquake away from the focus, through Earth s interior, and across the

### EARTHQUAKE PREDICTION

Lecture 15 Earthquake Prediction EARTHQUAKE PREDICTION To successfully predict an earthquake we would like to know:- PLACE TIME MAGNITUDE (rather like a weather forecast) 1 Evidence must be integrated

### Earthquakes and Seismic Waves ;Everything You need to know

Earthquakes and Seismic Waves ;Everything You need to know What Are Plate Tectonics? Seismic Zones Recycling of Crustal Material What is an earthquake? What are Seismic Waves? Magnitude and Intensity of

### Geological Maps 3: Faulted Strata

Geological Maps 3: Faulted Strata Brittle deformation in rocks is characterized by fractures, joints and faults. Fractures and joints can be of any size, orientation or pattern. Some joints form regular

### Name Crustal Interactions E-Science Date Midterm Review Science Department

Name Crustal Interactions E-Science Date Midterm Review Science Department 1 Base your answer to the following question on the cross section below, which shows the paths of seismic waves traveling from

### 3. When an earthquake occurs, energy radiates in all directions from its source, which is called the. a. epicenter c. fault b. focus d.

NAME EARTH SCIENCE CHAPTER 8 1. A fault is. a. a place on Earth where earthquakes cannot occur b. a fracture in the Earth where movement has occurred c. the place on Earth s surface where structures move

### Q1. Someone was sitting on one of these Mars bars for a while! Which one? How do you know? Q2. What do you think made the Mars bar go soft?

STRESSED OUT! People say they re stressed when they are under pressure. But other things get stressed too... Look at what happened when we tried to break these Mars bars. A B Q. Someone was sitting on

### Earth Science Chapter 8 Section 2 Review

Name: Class: Date: Earth Science Chapter 8 Section 2 Review Multiple Choice Identify the choice that best completes the statement or answers the question. 1. Which seismic waves travel most rapidly? a.

### Section 8.1 What Is an Earthquake? This section explains what earthquakes and faults are and what causes earthquakes.

Section 8.1 What Is an Earthquake? This section explains what earthquakes and faults are and what causes earthquakes. Reading Strategy Building Vocabulary As you read this section, write a definition for

### What is an earthquake?

Earthquakes and structural damage (and nifty examples of geophysical forensics) What is an earthquake? An earthquake is the vibration of Earth produced by the rapid release of energy Energy released radiates

### LESSON PLAN 3. Key Terms and Concepts. compression dip-slip fault epicenter longitudinal Love waves normal slip fault primary waves (P waves)

Learning about faults and seismic waves will give students a deeper understanding of earth tremors and quakes. Key Terms and Concepts Earthquake Science compression dip-slip fault epicenter longitudinal

### EARTH SCIENCE ACTIVITY #5 The Mercalli Scale

EARTH SCIENCE ACTIVITY #5 The Mercalli Scale All Grades 4 and Up This activity is one of several in a basic curriculum designed to increase student knowledge about earthquake science and preparedness.

### Geotechnical Earthquake Engineering

Geotechnical Earthquake Engineering by Dr. Deepankar Choudhury Professor Department of Civil Engineering IIT Bombay, Powai, Mumbai 400 076, India. Email: dc@civil.iitb.ac.in URL: http://www.civil.iitb.ac.in/~dc/

### FOURTH GRADE PLATE TECTONICS 1 WEEK LESSON PLANS AND ACTIVITIES

FOURTH GRADE PLATE TECTONICS 1 WEEK LESSON PLANS AND ACTIVITIES PLATE TECTONIC CYCLE OVERVIEW OF FOURTH GRADE VOLCANOES WEEK 1. PRE: Comparing different structures of volcanoes. LAB: Modeling three types

### Earthquake source mechanics

Earthquake source mechanics Lecture 6 Seismic moment Earthquake magnitude Richter magnitude scale M = log A( ) - log A 0 ( ) where A is max trace amplitude at distance and A 0 is at 100 km Surface wave

### Technical Newsletter GUIDE TO EARTHQUAKES - PART I. An introduction to Earthquakes: why and where they occur and how they are measured.

Technical Newsletter #29 - October 2015 GUIDE TO EARTHQUAKES - PART I An introduction to Earthquakes: why and where they occur and how they are measured Figure 1: Ratio of earthquake capacity purchase

### Task: Your task is to use earthquake data to map a possible fault line and then evaluate the risk of damage from earthquakes near this fault line.

Name Date Per Task: Your task is to use earthquake data to map a possible fault line and then evaluate the risk of damage from earthquakes near this fault line. Materials: Seismograms showing the arrival

### Presentations. Session 1. Slide 1. Earthquake Risk Reduction. 1- Concepts & Terminology

Earthquake Risk Reduction Presentations Session 1 Slide 1 Earthquake Risk Reduction 1- Concepts & Terminology Welcome to the World Bank Institute s (WBI) Distance Learning (DL) course on Earthquake Risk

### Seismographs. Lesson 7. Seismographs recording activity on Kilauea

Seismographs Lesson 7 E arthquakes generate seismic waves that travel all around the world and can be detected by sensitive instruments called seismographs. The earliest instrument to detect earthquakes

### Pd: Date: GEO. Natural Disasters

Name: Pd: Date: GEO Natural Disasters Tornadoes (Also called or ) They usually form in a giant rotating thunderstorm called a. Generally, tornadoes are about across, and travel at speeds of miles per hour,

### Glossary. continental crust: the sections of crust, the outermost layer of the earth, that include the continents

aftershock: an earthquake that follows a larger earthquake or main shock and originates in or near the rupture zone of the larger earthquake. Generally, major earthquakes are followed by a number of aftershocks

### Determination of source parameters from seismic spectra

Topic Determination of source parameters from seismic spectra Authors Michael Baumbach, and Peter Bormann (formerly GeoForschungsZentrum Potsdam, Telegrafenberg, D-14473 Potsdam, Germany); E-mail: pb65@gmx.net

### Magnitude 7.2 GUERRERO, MEXICO

A powerful magnitude-7.2 earthquake shook central and southern Mexico on Friday. The earthquake occurred at a depth of 24 km (15 miles). Its epicenter was in the western state of Guerrero, near the seaside

### Chapter. Earthquake Damage: Types, Process, Categories

3 Chapter Earthquake Damage: Types, Process, Categories Earthquakes leave behind a trail of damage and destruction. People s lives are affected by the loss of loved ones, destruction of property, economic

### Volcanoes and Earthquakes. Part 1: Volcanoes

Volcanoes and Earthquakes Part 1: Volcanoes Introduction Earth s crust is made of cool, solid rock. Yet, most of Earth is made of extremely hot rock in the mantle and liquid metal in the core. Sometimes,

### Electricity and Magnetism

Electricity and Magnetism Waves Wave a disturbance that travels through a medium in such a way that energy travels through the medium but matter does not. All waves (sound waves, waves on a string, seismic

### Earthquake Lab. A. Locate the Epicenter. Name: Lab Section:

Earthquake Lab Name: Lab Section: The goal of this portion of the lab is to learn how recording of earthquakes seismograms are used to locate earthquakes, determine their magnitudes, and to understand

### Earth. Earthquake Generation. A Violent Pulse: EARTHQUAKES! Chapter 10 CE/SC Portrait of a Planet Fifth Edition

CE/SC 10110-20110 A Violent Pulse: EARTHQUAKES! Earth Portrait of a Planet Fifth Edition Chapter 10 San Francisco Bay Area Earthquake Generation Brittle Deformation Bending = stress build up Break = energy

### Earthquakes and Tsunamis By: Sue Peterson

www.k5learning.com Objective sight words (tectonic plates, terrifying, anxiety-ridden, panic, equipped, imperative, aftershocks, subsided, horrified, urgent, reassemble, disorder, winding, treacherous);

### DYNAMIC CRUST: Unit 4 Exam Plate Tectonics and Earthquakes

DYNAMIC CRUST: Unit 4 Exam Plate Tectonics and Earthquakes NAME: BLOCK: DATE: 1. Base your answer to the following question on The block diagram below shows the boundary between two tectonic plates. Which

### Project Report. Structural Investigations Hotel del Sol Yuma, Arizona

Project Report Structural Investigations Yuma, Arizona Prepared by: 2619 Spruce Street Boulder, CO 80302 303-444-3620 Prepared for: Principle Engineering Group, Inc. 833 East Plaza Circle, Suite 100 Yuma,

### 2.1 REFRACTION SEISMOLOGY AND THE CRUST

2.1 REFRACTION SEISMOLOGY AND THE CRUST In 1885 all that was known about earth structure was a vague idea that the density inside had to be much greater than the surface. Within 50 years an incredible

### Magnitude and Intensity

Exercise 2 EXERCISE 2 EARTHQUAKE MAGNITUDE AND INTENSITY Supplies Needed calculator metric ruler PURPOSE Exercise 1 introduced many of the fundamental concepts of earthquakes, and this exercise will add

### Earthquakes and the Earth's Interior

Page 1 of 24 EENS 1110 Tulane University Physical Geology Prof. Stephen A. Nelson Earthquakes and the Earth's Interior This page last updated on 24-Sep-2015 Earthquakes Earthquakes occur when energy stored

### 4 Deforming the Earth s Crust

CHAPTER 4 4 Deforming the Earth s Crust SECTION Plate Tectonics BEFORE YOU READ After you read this section, you should be able to answer these questions: What happens when rock is placed under stress?

### Five reasons buildings fail in an earthquake and how to avoid them

Five reasons buildings fail in an earthquake and how to avoid them by Jeff White, AIA Published in Healthcare Design magazine There s a saying among seismologists: Earthquakes don t kill people. Buildings

### Building damage patterns in Kathmandu Valley due to 25th April Earthquake. Kiran Acharya

Building damage patterns in Kathmandu Valley due to 25th April Earthquake Kiran Acharya (acharyakiranraj@gmail.com, kacharya@baseengr.com) This report presents the nature of the earthquake that struck

### Earthquake Magnitude

Earthquake Magnitude Earthquake magnitude scales: Logarithmic measure of earthquake size amplitude of biggest wave: Magnitude 6 quake 10 * Magnitude 5 energy: Magnitude 6 quake is about 32 * Magnitude

### Investigation 3: Seismic Waves

Investigation 3: Seismic Waves Table of Contents: Folder 1: Seismic Waves... 25 Folder 2: Locating Earthquakes... 26 Folder 3: Exploring Earth s Interior... 29 Investigation Summary... 32 Folder 1: Seismic

### THE 2004 SUMATRA EARTHQUAKE AND INDIAN OCEAN TSUNAMI: WHAT HAPPENED AND WHY

Page 6 The Earth Scientist THE 2004 SUMATRA EARTHQUAKE AND INDIAN OCEAN TSUNAMI: WHAT HAPPENED AND WHY Seth Stein and Emile A. Okal Dept of Geological Sciences, Northwestern University, Evanston Illinois

### Rapid Changes in Earth s Surface

TEKS investigate rapid changes in Earth s surface such as volcanic eruptions, earthquakes, and landslides Rapid Changes in Earth s Surface Constant Changes Earth s surface is constantly changing. Wind,

### stress the amount of force per unit area that acts on a rock strain any change in a rock's shape or volume caused by stress Faults

----------------------------- -------- ------- Section 1 Review! deformation the bending, tilting, and breaking of Earth's crust; the change in the shape of rock in response to stress: fault a break in

### The Dynamic Crust 2) EVIDENCE FOR CRUSTAL MOVEMENT

The Dynamic Crust 1) Virtually everything you need to know about the interior of the earth can be found on page 10 of your reference tables. Take the time to become familiar with page 10 and everything

### Soil Dynamics Prof. Deepankar Choudhury Department of Civil Engineering Indian Institute of Technology, Bombay

Soil Dynamics Prof. Deepankar Choudhury Department of Civil Engineering Indian Institute of Technology, Bombay Module - 3 Wave Propagation - Earthquake waves Lecture - 17 P-waves, S-waves, 3 circle method,