Why do earthquake waves develop shadow zone

Tiffany Leonard Tiffany has worked on science curriculum and lesson writing since 2015. She has her Master's in Geology from the University of Illinois and a Bachelor's in Geology and Physics from Carleton College. She taught geology courses while she was getting her MS and was a TA while at Carleton. • Instructor What Is a Shadow Zone? An earthquake is the release of stress along a fault, as well as the motion generated by this release. The waves of energy released from the fault are called seismic waves. These waves can be separated into two types: surface waves and body waves. A body wave is a seismic wave that travels through the interior of the Earth rather than just at its surface. A seismic shadow zone is defined as an area on the surface of the Earth where certain types of seismic waves cannot be measured. At these locations, the complete behavior of the earthquake is not observed on a seismograph, an instrument used to record the motion of the Earth's surface caused by There are two distinct types of seismic shadow zones: • S-wave Shadow Zones • P-wave Shadow Zones These shadow zones are distinguished by the type of wave that cannot be measured in them. There are two distinct seismic shadow zones on the surface of the Earth. They are locations where P-waves and S-waves are not recorded due to the liquid outer core. What Causes a Seismic Shadow Zone? Shadow zones are created because the waves enter a medium through which travel is more difficult. In this case, the ...

Why is the S-wave shadow zone larger than the P-wave shadow zones are? The shadow zone of an earthquake is usually located 100-150 degrees from the epicentre. Depending on the type of wave the size of the shadow zone can vary. Since s waves cannot travel through the outer core, there waves hit a little more than half of the earth. This means that it has a large shadow zone. O waves do have the ability to pass through the outer core. But when this happens the waves refract and come out the other side on line with the anticenter. This creates about a 45 degree gap between the are the p waves were refracted to, and the area the p waves that didn't pass through the core ended up. This is where the P waves shadow zone is located.

Table of Contents • • • • • Why do shadow zones create earthquakes? The earthquake waves develop shadow zones because: (i)The P and S waves follow a curved path in the interior of the earth which proves that the density increases inside the earth. (iii)On reaching the core ‘S’ waves disappear and P waves are refracted as a result there is no wave for a distance. What is S wave paths and shadow zone? The S wave shadow zone is the area of the Earth’s surface where S waves are not detected following an earthquake. This shadow zone has led geologists to a model of the Earth with a solid mantle and a liquid core. Geologists have been able to calculate the size of the liquid core from these measurements. What is the importance of shadow zone? Seismic shadow zones have taught us much about the inside of the earth. This shows how P waves travel through solids and liquids, but S waves are stopped by the liquid outer core. The wave properties of light are used as an analogy to help us understand seismic-wave behavior. READ ALSO: What is the passive voice of RAM is playing football? Why do earthquake waves develop shadow zone Class 11? (iii) Earthquake waves develop shadow zones because of the properties of each (P and S) waves as well as the core. Outer crust is liquid and hence S-waves, which can travel only through solid material, is blocked and cannot move across the core. Why do earthquake waves develop shadow zone in 30 words? (i)The P and S waves follow a curved path in the in...

• SOLUTIONS Menu Toggle • NCERT Solution • Assam Board Menu Toggle • Assamese Medium Q/A • Bengali Medium Q/A • English Medium Q/A • Sankardev Shishu Niketan Q/A • Assam Jatiya Bidyalay Q/A • NIOS Study Material • COLLEGE [BA, B.COM, BSC] • SCHOOL [3 TO 10] • HS [11 & 12] • TET/B.ED • GRAMMAR • ESSAY WRITING • MCQ [QUIZ] • NOVEL • MORE [STORY, LETTER, APPLICATION, etc.] • CAREER GUIDE • BIO • FINANCE • JOB NEWS • QUOTES (i) Upper and lower mantle (ii) Crust and upper mantle (iii) Crust and core (iv) Mantle and core Ans. (ii) Crust and upper mantle (b) Answer the following questions in about 30 words. Q.1. What are body waves? Ans: At the time of Earthquake some waves originate, which are named as body waves and surface waves. Body waves are generated due to the release of energy at the focus and move in all directions travelling through the body of the earth. That is why it is named as body waves. Q.2. Name the direct sources of information about the interior of the earth. From the mines of different parts of the world it is known that with increasing the depth of mines the temperature as well as the density of the matter are increased. It means the interior parts of the earth remain in hot conditions. As and when the molten material (magma) is thrown onto the surface of the earth during volcanic eruption it becomes easy to estimate that the interior of the earth remains in hot and liquid conditions. Q.3. Why do earthquake waves develop shadow zones? Ans: The earthquake wa...

IRIS operates, provides, and maintains geoscience instrumentation IRIS facilitates seismological and geophysical research by operating and maintaining open geophysical networks and providing portable instrumentation for user-driven experiments. Instrumentation support includes engineering services, training, logistics, and best practices in equipment usage. All data collected with IRIS instrumentation are made freely and openly available. IRIS is a consortium of over 125 US universities dedicated to the operation of science facilities for the acquisition, management, and distribution of seismological data, and for fostering cooperation among IRIS members, affiliates, and other organizations in order to advance seismological research and education. Optional Files 2 • • How do P& S waves give evidence for a liquid outer core? The seismic shadows are the effect of seismic waves striking the core-mantle boundary. P and S waves radiate spherically away from an earthquake's hypocenter (or focus) in all directions and return to the surface by many paths. S waves, however, don't reappear beyond an angular distance of ~103° (as they are stopped by the liquid) and P waves don't arrive between ~103° and 140° due to refraction at the mantle-core boundary. CLOSED CAPTIONING:A .srtfile is included with the download. Use an appropriate media player to utilize captioning. Keypoints: • The seismic shadow zone is the rea of the Earth's surface where seismographs cannot detect an earthquake ...

1. Multiple choice questions Question 1(i). Which one of the following earthquake waves is more destructive? (a) P-waves (b) S-waves (c) Surface waves (d) None of the above. Answer: (a) P-waves Question 1(ii). Which one of the following is a direct source of information about the interior of the earth? (а) Earthquake waves (b) Volcanoes (c) Gravitational force (d) Earth magnetism. Answer: (а) Earthquake waves Question 1(iii). Which type of volcanic eruptions have caused Deccan Trap formations? (a) Shield (b) Flood (c) Composite (d) Caldera. Answer: (b) Flood Question 1(iv). Which one ofthe following describes the lithosphere? (a) Upper and lower mantle (b) Crust and upper mantle (c) Crust and core (d) Mantle and core. Answer: (b) Crust and upper mantle 2. Answer the following questions in about 30 words. Question 2(i). What are body waves? Answer: Body waves are generated due to the release of energy at the focus and move in all directions travelling through the body of the earth. Therefore, it has been named as body waves. These are of two types: P-waves and S-waves. Question 2(ii). Name the direct sources of information about the interior of the earth. Answer: Some of the direct sources are:- Mining: It is a process by which commercially variable valuable mineral resources are extracted from Earth’s surface which includes precious stones, rocks and solid fuels. Drilling: Scientists world over are working on two major projects such as “Deep Ocean Drilling Projects” and “I...

Why do earthquake waves develop shadow zone? There are two types of body waves which are called P and S waves. The behavior of these two waves is different. Due to this different behavior, we get to know about the internal structure of the earth. Seismic waves are recorded on the seismograph at distant places. But due to some specific property of the seismic wave, there are some areas where the seismic waves are not recorded on the seismograph, these areas are called shadow areas. image Sc: NCERT Shadow regions are formed because • The "P" wave can pass through solid, liquid, and gas, but its speed is different in different mediums. For example, the speed of the "P" wave in the solid medium is maximum; When the "P" wave reaches the outer core (the outer core is fluid), the speed and direction of the wave get changes, due to these reasons the P wave creates a shadow area between 105 degrees to 145 degrees from the earthquake's focus. • We know that S wave can pass through solid only when S wave reaches the outer core, it cannot pass through the outer core because of its liquid state. It did not reach beyond 105 degrees from the earthquake's focus.It creates more shadow area than a P wave.

Why do earthquake waves develop shadow zone? In shadow zone, seismograph does not record signals. For P-wave it is b/w 104-145 degress.These earthquake waves exhibit same properties as other waves like reflection, refraction etc.As core has denser matter so P-waves will bend inward and hences they will form a shadow zone. S-waves don't pass through liquid phase, core. So, shadow zone is larger here. What happens to P- and S- waves when they reach the center of the earth? P waves travel much faster than S waves so they reach the core faster. They can travel through the outer core, but change direction slightly, causing a p-waves shadow zone. S waves cannot travel through the outer core because it is liquid and has zero rigidity so they are diverted around it causing a much larger shadow zone called the S wave shadow zone. Surface, or L waves cannot travel through the earth at all. P-waves are observed directly opposite to the epicentre of earthquake which states that the wave passing through the earth as a diameter has no effect on its path.

Why do earthquake waves develop shadow zone? There are two types of body waves which are called P and S waves. The behavior of these two waves is different. Due to this different behavior, we get to know about the internal structure of the earth. Seismic waves are recorded on the seismograph at distant places. But due to some specific property of the seismic wave, there are some areas where the seismic waves are not recorded on the seismograph, these areas are called shadow areas. image Sc: NCERT Shadow regions are formed because • The "P" wave can pass through solid, liquid, and gas, but its speed is different in different mediums. For example, the speed of the "P" wave in the solid medium is maximum; When the "P" wave reaches the outer core (the outer core is fluid), the speed and direction of the wave get changes, due to these reasons the P wave creates a shadow area between 105 degrees to 145 degrees from the earthquake's focus. • We know that S wave can pass through solid only when S wave reaches the outer core, it cannot pass through the outer core because of its liquid state. It did not reach beyond 105 degrees from the earthquake's focus.It creates more shadow area than a P wave.

Why do earthquake waves develop shadow zone? In shadow zone, seismograph does not record signals. For P-wave it is b/w 104-145 degress.These earthquake waves exhibit same properties as other waves like reflection, refraction etc.As core has denser matter so P-waves will bend inward and hences they will form a shadow zone. S-waves don't pass through liquid phase, core. So, shadow zone is larger here. What happens to P- and S- waves when they reach the center of the earth? P waves travel much faster than S waves so they reach the core faster. They can travel through the outer core, but change direction slightly, causing a p-waves shadow zone. S waves cannot travel through the outer core because it is liquid and has zero rigidity so they are diverted around it causing a much larger shadow zone called the S wave shadow zone. Surface, or L waves cannot travel through the earth at all. P-waves are observed directly opposite to the epicentre of earthquake which states that the wave passing through the earth as a diameter has no effect on its path.