Earthquakes occur when energy is released along faults in the Earth's crust. The San Andreas fault extends through California and causes earthquakes like the 1906 San Francisco quake when the lands on either side move in opposite directions. Earthquakes can also trigger tsunamis and different types of seismic waves. Volcanoes form when magma reaches the Earth's surface through vents, erupting as either dark-colored basaltic lava flows or light-colored explosive rhyolitic eruptions. The three major zones of earthquake and volcanic activity are the Pacific Ring of Fire, the Mediterranean, and the Mid-Atlantic Ridge.
Earth is the third planet from the Sun and the only object in the Universe known to harbor life. According to radiometric dating and other sources of evidence, Earth formed over 4 billion years ago.[24][25][26] Earth's gravity interacts with other objects in space, especially the Sun and the Moon, Earth's only natural satellite. Earth revolves around the Sun in 365.26 days, a period known as an Earth year. During this time, Earth rotates about its axis about 366.26 times.[n 5]
Earth's axis of rotation is tilted, producing seasonal variations on the planet's surface.[27] The gravitational interaction between the Earth and Moon causes ocean tides, stabilizes the Earth's orientation on its axis, and gradually slows its rotation.[28] Earth is the densest planet in the Solar System and the largest of the four terrestrial planets.
Earth's lithosphere is divided into several rigid tectonic plates that migrate across the surface over periods of many millions of years. About 71% of Earth's surface is covered with water, mostly by oceans.[29] The remaining 29% is land consisting of continents and islands that together have many lakes, rivers and other sources of water that contribute to the hydrosphere. The majority of Earth's polar regions are covered in ice, including the Antarctic ice sheet and the sea ice of the Arctic ice pack. Earth's interior remains active with a solid iron inner core, a liquid outer core that generates the Earth's magnetic field, and a convecting mantle that drives plate tectonics.
Within the first billion years of Earth's history, life appeared in the oceans and began to affect the Earth's atmosphere and surface, leading to the proliferation of aerobic and anaerobic organisms. Some geological evidence indicates that life may have arisen as much as 4.1 billion years ago. Since then, the combination of Earth's distance from the Sun, physical properties, and geological history have allowed life to evolve and thrive.[30][31] In the history of the Earth, biodiversity has gone through long periods of expansion, occasionally punctuated by mass extinction events. Over 99% of all species[32] that ever lived on Earth are extinct.[33][34] Estimates of the number of species on Earth today vary widely;[35][36][37] most species have not been described.[38] Over 7.4 billion humans live on Earth and depend on its biosphere and natural resources for their survival. Humans have developed diverse societies and cultures; politically, the world has about 200 sovereign states.
Earth is the third planet from the Sun and the only object in the Universe known to harbor life. According to radiometric dating and other sources of evidence, Earth formed over 4 billion years ago.[24][25][26] Earth's gravity interacts with other objects in space, especially the Sun and the Moon, Earth's only natural satellite. Earth revolves around the Sun in 365.26 days, a period known as an Earth year. During this time, Earth rotates about its axis about 366.26 times.[n 5]
Earth's axis of rotation is tilted, producing seasonal variations on the planet's surface.[27] The gravitational interaction between the Earth and Moon causes ocean tides, stabilizes the Earth's orientation on its axis, and gradually slows its rotation.[28] Earth is the densest planet in the Solar System and the largest of the four terrestrial planets.
Earth's lithosphere is divided into several rigid tectonic plates that migrate across the surface over periods of many millions of years. About 71% of Earth's surface is covered with water, mostly by oceans.[29] The remaining 29% is land consisting of continents and islands that together have many lakes, rivers and other sources of water that contribute to the hydrosphere. The majority of Earth's polar regions are covered in ice, including the Antarctic ice sheet and the sea ice of the Arctic ice pack. Earth's interior remains active with a solid iron inner core, a liquid outer core that generates the Earth's magnetic field, and a convecting mantle that drives plate tectonics.
Within the first billion years of Earth's history, life appeared in the oceans and began to affect the Earth's atmosphere and surface, leading to the proliferation of aerobic and anaerobic organisms. Some geological evidence indicates that life may have arisen as much as 4.1 billion years ago. Since then, the combination of Earth's distance from the Sun, physical properties, and geological history have allowed life to evolve and thrive.[30][31] In the history of the Earth, biodiversity has gone through long periods of expansion, occasionally punctuated by mass extinction events. Over 99% of all species[32] that ever lived on Earth are extinct.[33][34] Estimates of the number of species on Earth today vary widely;[35][36][37] most species have not been described.[38] Over 7.4 billion humans live on Earth and depend on its biosphere and natural resources for their survival. Humans have developed diverse societies and cultures; politically, the world has about 200 sovereign states.
Volcanoes , What Causes Volcanoes , Volcanic Landforms: Extrusive & Intrusive Volcanic Landforms , Distribution of Volcanoes around the Globe
, Effects of Volcanism , Reasons for Concentration of volcanoes along the Ring of Fire .
this power point talks about the causes, impacts and management strategies of volcanoes. it describe about the types of lava flow and types of volcanoes also,
Grade 8 Integrated Science Chapter 15 Lesson 2 on volcanoes. This lesson goes into detail about volcanoes, plate boundaries, lava chemistry, eruption types, and volcano types. The purpose of this lesson is for students to understand where and why volcanoes form and what factors cause differing volcanic features.
Volcanoes , What Causes Volcanoes , Volcanic Landforms: Extrusive & Intrusive Volcanic Landforms , Distribution of Volcanoes around the Globe
, Effects of Volcanism , Reasons for Concentration of volcanoes along the Ring of Fire .
this power point talks about the causes, impacts and management strategies of volcanoes. it describe about the types of lava flow and types of volcanoes also,
Grade 8 Integrated Science Chapter 15 Lesson 2 on volcanoes. This lesson goes into detail about volcanoes, plate boundaries, lava chemistry, eruption types, and volcano types. The purpose of this lesson is for students to understand where and why volcanoes form and what factors cause differing volcanic features.
Unit 8 - Information and Communication Technology (Paper I).pdfThiyagu K
This slides describes the basic concepts of ICT, basics of Email, Emerging Technology and Digital Initiatives in Education. This presentations aligns with the UGC Paper I syllabus.
Operation “Blue Star” is the only event in the history of Independent India where the state went into war with its own people. Even after about 40 years it is not clear if it was culmination of states anger over people of the region, a political game of power or start of dictatorial chapter in the democratic setup.
The people of Punjab felt alienated from main stream due to denial of their just demands during a long democratic struggle since independence. As it happen all over the word, it led to militant struggle with great loss of lives of military, police and civilian personnel. Killing of Indira Gandhi and massacre of innocent Sikhs in Delhi and other India cities was also associated with this movement.
Instructions for Submissions thorugh G- Classroom.pptxJheel Barad
This presentation provides a briefing on how to upload submissions and documents in Google Classroom. It was prepared as part of an orientation for new Sainik School in-service teacher trainees. As a training officer, my goal is to ensure that you are comfortable and proficient with this essential tool for managing assignments and fostering student engagement.
How to Split Bills in the Odoo 17 POS ModuleCeline George
Bills have a main role in point of sale procedure. It will help to track sales, handling payments and giving receipts to customers. Bill splitting also has an important role in POS. For example, If some friends come together for dinner and if they want to divide the bill then it is possible by POS bill splitting. This slide will show how to split bills in odoo 17 POS.
Welcome to TechSoup New Member Orientation and Q&A (May 2024).pdfTechSoup
In this webinar you will learn how your organization can access TechSoup's wide variety of product discount and donation programs. From hardware to software, we'll give you a tour of the tools available to help your nonprofit with productivity, collaboration, financial management, donor tracking, security, and more.
How to Create Map Views in the Odoo 17 ERPCeline George
The map views are useful for providing a geographical representation of data. They allow users to visualize and analyze the data in a more intuitive manner.
This is a presentation by Dada Robert in a Your Skill Boost masterclass organised by the Excellence Foundation for South Sudan (EFSS) on Saturday, the 25th and Sunday, the 26th of May 2024.
He discussed the concept of quality improvement, emphasizing its applicability to various aspects of life, including personal, project, and program improvements. He defined quality as doing the right thing at the right time in the right way to achieve the best possible results and discussed the concept of the "gap" between what we know and what we do, and how this gap represents the areas we need to improve. He explained the scientific approach to quality improvement, which involves systematic performance analysis, testing and learning, and implementing change ideas. He also highlighted the importance of client focus and a team approach to quality improvement.
2. Earthquakes
• An earthquake is the shaking and
trembling that results from the sudden
movement of part of the Earth’s crust.
• The most common cause of earthquakes
is faulting. During faulting, energy is
released. Rocks continue to move until
the energy is used up.
3. San Andreas Fault
• The San Andreas fault extends 960 km
from Mexico to the north of California.
• The land to the west is moving north. The
land to the east of the fault is moving
south. All the rocks do not move at the
same time so earthquakes occur in one
area and then another.
4. San Francisco Quake
• IN 1906, movement along the San
Andreas fault caused an earthquake in
San Francisco.
5. Tsunamis
• Earthquakes which occur on the ocean
floor produce giant sea waves called
tsunamis. Tsunamis can travel at speeds
of 700 to 800 km per hour. As they
approach the coast, they can reach
heights of greater than 20 meters.
6. Focus
• Most faults occur between the surface and
a depth of 70 kilometers.
• The point beneath the surface where the
rocks break and move is called the focus.
The focus is the underground origin of an
earthquake.
7. Epicenter
• Directly above the focus, on the Earth’s
surface is the epicenter. Earthquake
waves reach the epicenter first. During an
earthquake, the most violent shaking is
found at the epicenter.
8. Seismic Waves
• There are three main types of seismic
waves.
• Primary
• Secondary
• Surface
9. Primary Waves
• Seismic waves that travel fastest are P
waves. They travel through solids, liquids
and gases.
• They move at different speeds depending
on the density of the material through
which they are moving. As they move
deeper in the Earth they move faster.
• P waves are push-pull waves.
10. Secondary Waves
• Seismic waves that do not travel through
the Earth as fast as P waves do are called
secondary or S waves.
• S waves travel through solids but not
liquids or gases.
• S waves cause particles to move from side
to side. They move at right angles to the
direction of the wave.
11. Surface Waves
• The slowest moving seismic waves are
called surface waves or L waves.
• L waves originate on the Earth’s surface at
the epicenter. They move along the
surface the way waves travel in the ocean.
The Earth’s surface moves up and down
with each L wave.
• L waves cause most of the damage.
12. The Seismograph
• Invented in 1893 by John Milne, a
seismograph detects and measures
seismic waves.
• A weight attached to a spring remains
nearly still even when the Earth moves. A
pen attached to the weight records any
movement on a roll of paper on a
constantly rotating drum. The drum moves
with the Earth and affects the line.
13. Seismologists
• Seismologists study earthquakes. They
can determine the strength of an
earthquake by the height of the wavy line
recorded on the paper.
• The seismograph record of waves is called
a seismogram.
• The Richter scale is used to calculate the
strength of an earthquake.
14. The Richter Scale
• The amount of damage created by an
earthquake depends on several factors.
• The earthquake’s strength
• The kind of rock and soil that underlie an
area
• The population of the area
• The kind of buildings in the area
• The time at which the earthquake occurs
15. Predicting Earthquakes
• Scientists have identified warning signals
the help predict earthquakes with greater
accuracy.
• Often changes occur in the speed of P and
S waves before an earthquake occurs.
• Sometimes slight changes in the tilt of the
Earth’s surface can be detected.
• Some scientists believe animals behavior
is affected.
17. Magma
Deep within the Earth, under tremendous
pressure and at great temperatures, rock
exists as a hot liquid called magma. This
molten rock is found in pockets called
magma chambers.
18. Lava
• When the magma reaches the surface, it
is called lava. The place in the Earth’s
surface through which magma and other
materials reach the surface is called a
volcano. In some places, lava can build
up to forma cone-shaped mountain.
• The opening from which lava erupts is the
vent. Volcanoes often have more than
one vent.
19. Dark-Colored Lava
• There are four types of lava.
• One is dark-colored and contains a lot of
water. This is rich in iron and magnesium
and cools to form igneous rocks such as
basalt. This lava is thin and runny and
most tends to flow. The islands of Hawaii
and Iceland were formed by many lava
flows.
20. Light-Colored Lava
• The second type of lava is light in color.
This lava, contains little water and is rich in
silicon and aluminum. Light-colored lava
causes explosive eruptions. Silicon tends
to harden in the vents and form rocks.
Steam and new lava build up under the
rocks. When the pressure becomes great,
a violent explosion occurs. When this type
of lava cools it form the igneous rock,
rhyolite, which resembles granite.
21. Combination Lava
• The third type of lava has a chemical
composition similar to that of both the
dark-colored type and the light-colored
type. Different varieties of igneous rocks
in the Earth’s crust, such as andesite, are
form from this type of lava.
22. Gaseous Lava
• The fourth type of lava contains large
amounts of gases such as steam and
carbon dioxide. When this lava hardens, it
forms rocks with many holes in them, due
to gas bubbles. Pumice and scoria are
igneous rocks formed from this type of
lava.
23. Volcanic Eruptions
• During volcanic eruptions, many rock
fragments are blown into the air. The
smallest particles are called volcanic dust.
(less than 0.25 mm)
• Volcanic Ash ( 0.25 -5mm) falls to the
Earth and forms small rocks.
• Volcanic bombs (a few cm to several
meters) are molten and harden as they
travel through the air.
24. Types of Volcanoes
• Different types of volcanic eruptions form
different types of volcanoes.
• Cinder cones
• Shield volcanoes
• Composite volcanoes
25. Cinder Cones
• Volcanoes made mostly of cinders and
other rock particles that have been blown
into the air are called cinder cones.
Cinder cones form from explosive
eruptions. Because the material is loosely
arranged, the cones are not high. The
have a narrow base and steep sides such
as Paricutin in Mexico.
26. Shield Volcanoes
• Volcanoes composed of quiet flows are
called shield volcanoes. Because it is
rummy, the lava flows over a large area.
After several eruptions, a dome-shaped
mountain is formed such as Mauna Loa
(4km over sea level) in the Hawaiian
Islands.
27. Composite Volcanoes
• Volcanoes built up of alternating layers of
rock particles and lava are called
composite volcanoes. During the
formation of a composite volcano, a violent
eruption first occurs, hurling volcanic
bombs, cinder and ash out of the vent.
Then a quiet eruption, produces lava flow
that covers the rock particles. After
alternating eruptions, a cone-shaped
mountain forms such as Mount Vesuvius.
28. Crater
• There is often a funnel-shaped pit or
depression at the top of a volcanic cone.
This pit is called a crater. If the crater
becomes very large as a result of the
collapse of its walls, it is called a caldera.
A caldera may also form when the top of a
volcano explodes or collapses.
29. Volcanic Activity
• Volcanoes are rather unpredictable .
Some erupt regularly, others have not
erupted in modern history. Scientists
classify them as active, dormant or extinct.
30. Active Volcanoes
• An active volcano is one that erupts wither
continually or periodically such as Mount
Katmai in Alaska and Mount St. Helens in
the Cascade Range.
31. Dormant Volcano
• A volcano that has been known to erupt
within modern times but is now inactive is
classified as a dormant volcano. Mount
Rainier in Washington state are example
of dormant volcanoes in the United States.
32. Extinct Volcano
• A volcano not known to have erupted
within modern history is classified as an
extinct volcano. They have been worn
away almost to the level of their magma
chamber. Scientists can be wrong. Mount
St. Helens was considered to be dormant
but erupted after long periods of inactivity.
33. Volcano and Earthquake Zones
• Most major earthquakes and volcanic
eruptions occur in three zones of the
world. Scientists believe that there is a
great deal of movement and activity in the
Earth’s crust in these three zones.
34. Ring of Fire
• One major earthquake and volcano zone
extends nearly all the way around the
edge of the Pacific Ocean. This zone
goes through New Zealand, the
Philippines, Japan, Alaska and along the
western coasts of North and South
America. The San Andreas fault is part of
this zone.
35. Mediterranean Zone
• A second Major earthquake and volcano
zone is located near the Mediterranean
Zone and extends across Asia into India.
Many countries in the zone, including Italy,
Greece and Turkey, have violent
earthquakes. Many volcanic eruptions
also occur in this zone.
36. Mid-Atlantic Ridge Zone
• The third major earthquake and volcano
zone extends through Iceland and to the
middle of the Atlantic Ocean. There is
under the ocean a long range of volcanic
mountains called the Mid-Atlantic Ocean
Range. Scientists believe that the volcano
and earthquake activity are due to the
formation of new parts of the Earth’s crust
along the ridge. The volcanic island of
Iceland is part of this zone.