3 types of measuring earthquakes pdf

Volcanoes and earthquakes for twocolumn notes, underlined titles are main ideas. The richter magnitude scale was developed in 1935 by. A number of scales are used to measure earthquakes. Post assessment concepts addressed earthquakes indicate plate movement along faults in california.

The zigzag line made by a seismograph, called a seismogram, reflects the changing intensity of the vibrations by responding to the motion of the ground surface beneath the instrument. A tectonic earthquake is one that occurs when the earths crust breaks due to geological forces on rocks and adjoining plates that cause physical and chemical changes a volcanic earthquake is any earthquake that results from tectonic forces which occur in conjunction with. Earthquakes take time tooccur the larger the earthquake, the longer the source scaling law. Can cause major damage to poorly constructed buildings over small regions. Learn more about the causes and effects of earthquakes in this article. For large earthquakes worldwide, the moment magnitude scale mms is most common, although m s is also reported frequently. Richter scale equals a 30fold increase in energy released. Align 3 bricks in the centre of a table to minimize chance bricks falling off table. Earthquakes always begin in rock below the surface in the lithosphere. Because of various shortcomings of the m l scale most. By contrast, intensity indicates the local effects and potential for damage produced by an. Chapter 8 earthquakes section 2 earthquake measurement.

Earthquakes measuring upwards of 7 are less frequent but very powerful, and can cause a lot of destruction. This is the number that is typically used by the press when a big earthquake happens. The principal elements of a seismogram that interest seismologists scientists who study earthquakes are the relative size of the recorded waves and the difference in time that the first p and s waves were recorded. The seismograph and the seismoscope are the two main instruments used to measure the strength of earthquakes. Q12 are seismic intensity and earthquake magnitude different. The focus is the point on the fault surface where motion begins. The richter scale is most common in the united states, while worldwide, scientists rely on the mercalli scale. The richter scale measures the magnitude of an earthquake how powerful it is.

Earthquakes, until recently, have been measured on the richter scale. Measuring earthquakes california academy of sciences. A fault is a break in the crust that rocks slide along. Volcanoes and earthquakes miamidade county public schools. The science behind earthquakes what is an earthquake. Concept mappinguse the following terms to complete the concept map to organize some of the major ideas in this section. The powerful earthquake that struck japan in march was a 9. An earthquake also known as a quake, tremor or temblor is the shaking of the surface of the earth resulting from a sudden release of energy in the earths lithosphere that creates seismic waves. Scales have limited range and applicability and do not satisfactorily measure the size of the largest earthquakes. The surface where they slip is called the fault or fault plane. Reading strategy outlining as you read, fill in the outline with the important ideas in this section. Comparison of magnitude, intensity, and energy equivalent for. Earthquakes actually occur because the plates floating on the crust.

The largest earthquake ever recorded was in chile in 1960, which measured 9. The movement of the plates causes pressure to build up. Modified mercalli scale scale divided into 12 levels based on observed effects same earthquake can receive different rating at different locations. Primary waves, or pwaves, squeeze and pull rocks in the same direction along which the waves are traveling. Reverse faults are fractures that form as a result of horizontal compression. It used a formula based on amplitude of the largest wave recorded on a specific type of seismometer and the distance between the earthquake.

The richter scale calculates the strength of an earthquake based on measurements of the amplitude of the largest wave recorded on a seismometer as. During the course of this unit, encourage students to browse through newspapers to see if they can find information about natural disasters that have recently happened somewhere in the world. Chapter 8 earthquakes section 1 what are earthquakes. An earthquake also known as a quake, tremor or temblor is the shaking of the surface of the earth resulting from a sudden release of energy in the earth s lithosphere that creates seismic waves. What are three types of scales that measure earthquakes answers.

Use the concepts of elastic and ductile deformation to explain this fact. Based on what you have learned about the scale for measuring the strength of an earthquake, a. There can be three types of movement in these diagrams, the hanging wall is the side that moves up or down. Explosive earthquakes are often manmade, and the two terms may be used interchangeably. It is a measure of the size of the earthquake source and is the same number no matter where you are or what the shaking feels like. These occur when rocks in the earths crust break due to geological forces created by movement. Forces in the earth tension, compression, shearing cause stress at plate boundaries. One type of stress that we are all used to is a uniform stress. In other words, the vibrations of an earthquake measuring 6 on this scale would be 30 times more energetic than those of a quake measuring 5.

Inthe case of sumatra, full size available only from normal modes. An earthquake is what happens when two blocks of the earth suddenly slip past one another. In later sections of this course, we will take a closer look at evaluating a communitys safety. The seismoscope is a simple instrument that measures the time that an earthquake takes place. Earthquakes are recorded by a seismographic network.

The location below the earths surface where the earthquake starts is called the hypocenter, and the. An example of p and s seismic wave records is shown in figure 11. Three types of unequal stress on the earths crust are compression, tension, and shear. Earthquake, any sudden shaking of the ground caused by the passage of seismic waves through earths rocks. The vibrations produced by earthquakes are detected, recorded, and measured by instruments call seismographs. An increase of 1 number on the moment magnitude scale means 32 times more energy was released by the earthquake. Therefore, earthquakes are most frequent along the edges of the tectonic plates where one plate is moving relative to the adjoining plate. The seismograph records the motion of the ground during an earthquake. What are three types of scales that measure earthquakes. Richter and presented in his landmark 1935 paper, where he called it the magnitude scale. Earthquakes earthquakes occur when energy stored in elastically strained rocks is suddenly released. The record of an earthquake at a seismograph station is a. Fewer than 20 earthquakes occur each year, on average, that are considered major magnitude 7. Unit 3 earthquake causes and characteristics introduction in the last unit, we explored the historical importance and intent of executive order 12699.

Baxter introduction every year approximately 3,000,000 earthquake s occur worldwide. Types of fossilization most fossils are preserved by one of five processes outlined below figure below. Measures you can take to stay safe from earthquakes. Earthquakes teacher notes and student activities ga. The grade 6 earth science unit on earthquakes and volcanoes is presented to students through a series of investigations using indirect evidence models and direct evidence, experiments, active learning experiences, researching using a variety of sources, questions, and assessments. Types of faultsthere are three basic types of faults, as shown in figure 193. Scientists measure seismic waves produced by an earthquake using devices such as a seismograph or seismometer. A magnitude scale measures the force or energy of an earth. Stress arises because the fractured crust rides on a ductile mantle which slowly flows in convection currents. Learn vocabulary, terms, and more with flashcards, games, and other study tools. The deadly izmit earthquake struck northwest turkey on august 17, 1999, at 3 a. Earthquakes earthquakes are serious natural hazards that affect people across the globe, sometimes at long distances from where the quakes occur. The three major scales used to measure earthquakes are. Earthquakes happen when two large pieces of the earths crust suddenly slip.

Causes and measurements earthquakes the objectives of this part of the course will to be gain an understanding of the science of earthquakes so that we can answer the following questions. It includes information on faults, epicenter, kinds of faults normal, strikeslip and reverse, types of waves pwaves, swaves and surface waves and measuring earthquakes with seismograph and richter scale. Scales 1 3 have limited range and applicability and do not satisfactorily measure the size of the largest earthquakes. Measuring earthquakes m easuring the magnitude and intensity of earthquakes is subject to enormous misunderstanding. Over 14,000 residents of the region were killed as poorly constructed. Types of earthquakes southern california earthquake center. But this was not, as some people may assume, as registered on. Thus, a 6magnitude earthquake is 10 times greater than a 5magnitude earthquake. Earthquake waves types of seismic waves forces within earth the vibrations of the ground during an earthquake are called seismic waves. Movement at plate boundaries produces different types of faults. When source zone is used to categorize earthquakes, the primary earthquake types are shallowfault, deep zone and crustal earthquakes. The slip of one block of rock over another in an earthquake releases energy that makes the ground vibrate.

Body waves are of two types, pwaves, or primary or compression waves like the compression of the coils of a spring, and swaves, or secondary or shear waves like the flick of a rope. Measuring earthquakes teacher and youth education, 2012 3 do the lines created by the pen in the seismograph figure 3 look like anything youve seen before. The statement the three major scales used to measure earthquakes are mercalli scale, richter scale and magnitude scale is true. When earthquakes are categorized by cause, types include tectonic earthquakes, volcanic earthquakes and explosive earthquakes. Earthquake magnitude earthquake severity richter magnitude earthquake effects less than 3.

Use the green headings as the main topics and the blue headings as subtopics. M l is the scale used for the majority of earthquakes reported tens of thousands by local and regional seismological observatories. The plates of the crust collide in some places, pull apart in others, and sometimes grind against each other. Each earthquake produces three basic types of seismic waves. Earthquakes are put in the context of the large and smallscale changes that are constantly at work on the continents as well as the ocean floor. Describe three types of folds in the earths crust 5. What evidence in figure 193aindicates this shortening. Note that the compressional force results in a horizontal shortening of the crust involved. There are two fundamentally different types of scales commonly used by seismologists to describe earthquakes. Two of the most common methods used to measure earthquakes are the richter scale and the moment magnitude scale. Three types of stress on the earths crust sciencing. Magnitude is the most common measure of an earthquake s size.

Measuring large earthquakes at small periods simply misses their true size. This was later revised and renamed the local magnitude scale, denoted as ml or m l. These plates slowly move over a long period of time. Earthquakes teacher notes and student activities 7 the causes and types of earthquakes most earthquakes are caused by the movement of the earths tectonic plates. You need at least 3 seismic stations to locate an epicenter. Download fulltext pdf measuring earthquakes from optical satellite images article pdf available in applied optics 3920. Introduction to earthquakes in order to know where an earthquake was centered, you need to know where it began. The moment magnitude scale is another earthquake measurement scale used by some seismologists. In fact, earthquake waves can echo and be detected in different parts of the world. A seismograph, or seismometer, is an instrument used to detect. Earthquakes usually occur on the edges of large sections of the earths crust called tectonic plates. If the stress is applied quickly for example, because of an extraterrestrial impact or an earthquake, there will be an increased tendency for the rock to fracture. This release of energy causes intense ground shaking in the area near the source of the earthquake and sends waves of elastic energy, called seismic waves, throughout the earth.

Ninety eight percent of them are less than a magnitude 3. The type of earthquake depends on the region where it occurs and the geological makeup of that region. Earthquakes occur most often along geologic faults, narrow zones where rock masses move in relation to one another. Read the article, what makes earthquakes below then. Earthquakes measuring 9 or more on this scale are rare. The mercalli scale also measures the effects of an earthquake at different locations. The moment magnitude mw scale, based on the concept of seismic moment, is uniformly applicable to all sizes of earthquakes but is more difficult to compute than the other types. The moment magnitude mw scale, based on the concept of seismic moment, is uniformly applicable to all sizes of earthquakes but is.

Hence the seismic moment of an earthquake is a direct measure of the strength of. It is often referred to as richter magnitude, but that is a misnomer, and it should be just magnitude. The larger the earthquake, the longer the source scaling law. Earthquakes can range in size from those that are so weak that they cannot be felt to those violent enough to propel objects and people into the. The epicenter is the point on earths surface directly above the focus. A seismographs main component is a hanging mass as heavy as. Chapter 8 earthquakes and earths interior section 8. If you draw a circle on a map around three different. The plate boundaries should be drawn along the areas with large numbers of earthquakes. Eulo vocab measuring and locating earthquakes earth science learn with flashcards, games, and more for free. The first of these is an estimate of the energy released, and the value is referred to as magnitude. That vibration pushes the adjoining piece of ground and causes it to vibrate, and thus the energy travels out from the earthquake. Each student is given a worksheet to record their groups observations set up. Historically, earthquakes were measured on the richter.

Dec 25, 2019 earthquakes an earthquake is shaking or trembling of the earths surface, caused by the seismic waves or earthquake waves that are generated due to a sudden movement sudden release of energy in the earths crust shallowfocus earthquakes or upper mantle some shallowfocus and all intermediate and deepfocus earthquakes. Pdf measuring earthquakes from optical satellite images. Earthquakes can range in size from those that are so weak that they cannot be felt to those violent enough to propel objects and people into the air, and wreak destruction across entire cities. By using aids, such as the index and contents pages of the books, ask students to investigate different types of natural disasters. There are two primary scales used to measure earthquakes. Each seismic wave has a different type of motion and travels through the earth at different speeds. A magnitude scale measures the force or energy of an earth quake, but an intensity scale measures the level of shaking which occurs at an observation point on the earths surface. The richter scale also called the richter magnitude scale or richters magnitude scale is a measure of the strength of earthquakes, developed by charles f. First we need some basic information about earthquakes and their effects on the built environment. The richter scale measures the largest wiggle amplitude on the recording, but other magnitude scales measure different parts of the earthquake. Some different types of strain response are illustrated in figure 12. Every earthquake generates three types of seismic waves. Magnitude scales give an indication of the amount of energy.

This causes shock waves to shake the surface of the earth in the form of an earthquake. Each seismic station in the network measures the movement of the ground at that site. Sp23 earthquake basics the delaware geological survey. The familiar richter scale which is not a physical device but rather a mathematical formula is no longer widely used by scientists or the media to report an earthquake s size.