Earthquakes, Volcanoes, and Tsunamis


hello my name is Kylie and welcome to
earthquakes volcanoes and tsunamis in this video you’ll learn about all the
parts of the earth and how it shakes rattles and blasts let’s get down to
earth seen from space
planet Earth is composed of land and water but did you know that the earth is
made up of more than what the eye can see the surface of the earth where we
live is called the crust it is actually a thin layer of rock underneath the
crust is a layer of very hot sometimes melted or molten rock called the mantle
and at the very center of the earth there is the core the deeper into the
earth we go the hotter it gets the core is actually made up of two parts the
outer core and the inner core the outer core is made up of molten or melted rock
and it is like the texture of pudding and the inner core is solid speaking of solid let’s take a hard look
at natural events that have shaped land over time although we don’t feel it the
surface of the earth or the crust is always moving the continents drift apart
and the oceans move too by rising and falling over time all of the earth’s
movements have caused the crust to break up these broken up pieces of surface
rock are called tectonic plates because they are like gigantic plates floating
on the Earth’s mantle these plates moving caused the continents to drift
also known as continental drift geologists or scientists who study the
earth mapped out the seven major boundaries of the Earth’s tectonic
plates they include the Pacific plate the North American plate the Eurasian
Plate the African plate and the Antarctic plate also the indo-australian
plate and the South American plate that’s a lot of plates did you know that
mountains and volcanoes are formed because of these plates moving and did
you know that earthquakes are caused by these plates crashing together
I know it’s earth-shattering depending on where you live you might have already
experienced an earthquake or two earthquakes our shifts of the tectonic
plates when the plates collide they scrape against each other really
violently and create trembles and shakes on the Earth’s crust called an
earthquake imagine two very hard surfaces trying to slide past each other
but they are not going to glide smoothly like liquids do their force is so great
that they can actually cause intense shockwaves through the surface of the
earth sometimes causing a lot of damage to entire cities why couldn’t the two tectonic plates be
friends because there is too much friction between them the plate edges
that bang up against each other are called fault lines you may have heard
that the place is most likely to have earthquakes are those along fault lines
that’s why some states or provinces have more chances of earthquakes than others
the San Andreas Fault that’s where I live is a fault line that runs through
California and is 750 miles long there are three main types of faults
strike-slip fault normal fault and reverse faults strike-slip faults are
rocks sliding past each other horizontally or side-to-side the San
Andreas is a strike-slip fault normal faults are two blocks of crust
spreading apart to create a space or a valley such as the Basin and Range
province in the western USA and reverse faults are when one block of crust is
thrust above another these types of faults are found where tectonic plates
push up mountain ranges like in the Rocky Mountains or the Himalayas don’t
worry it’s not your fault if you can’t remember all this information at once
you’ll get a chance to practice later scientists who study earthquakes are
called seismologists and they use a scale to measure the force of an
earthquake this scale is called the Richter scale and it measures the
intensity or magnitude of earthquakes on a scale of one to ten where one is not
powerful and 10 is tremendously destructive you might sometimes hear
that an earthquake measured 6.2 on the Richter scale this means depending on
how long it quaked the damage to a city can be quite serious earthquakes have
aftershocks or a series of smaller tremors that happen following a really
large earthquake we know that they’re actually aftershocks and
not another earthquake because they occur in the same area and zone as a
major earthquake did just at a lower magnitude this focus point or the point
where the earthquake first starts is called the epicenter here’s a fun fact
every hour the earth quakes about 900 times but most of them cannot be felt by
humans because they are minor itty bitty quakes whoo
tectonic plates are constantly shifting also which causes other things to happen
to the earth when magma or molten rock from the Earth’s mantle pushes the
surface of the earth the pressure of the magma forms domes or mountains some
mountains have a giant hole in it because the pressure of the magma is so
strong when this happens it creates what we know of as a volcano the heat and
high pressure in the magma chambers causes an eruption the molten rock is
forced up the volcanoes pipe and pours out to opening or crater of the volcano
when magma reaches the Earth’s surface it’s called lava lava is like a river of
fire that flows out of the volcano and open throws pieces of rock and ash in
the air it also spews out gases and poisonous
fumes not all volcanoes are the same some are dormant or extinct because they
have not erupted in centuries some volcanoes are younger than others and
some are flat and not dome shaped at all there is a major Zone in the basin of
the Pacific Ocean where many volcanoes and earthquakes occur it’s called the
Ring of Fire because it’s an enclosed area shaped
like a horseshoe you can visit volcanoes around the world
like in Costa Rica Japan and even in the USA did you know that the Hawaiian
Islands are actually volcanoes that started underwater and have grown
through eruptions over many years what on earth yeah it’s true both volcanoes and
earthquakes can happen underwater – when tectonic plates shift the shaking of the
ocean floor causes the water to rise so high that it creates a high wall of
water known as a tsunami tsunamis grow in size the closer and closer they get
to shore and it can rise as high as a hundred feet that’s higher than a seven
story building Wow some people confuse tidal waves with tsunamis but they are
not the same tidal waves which are high sea waves can be caused by tsunamis but
they can also be caused by storms and very strong winds because of underwater
volcanic activity the ocean floor actually spreads this is called seafloor
spreading and it happens slowly over time along the mid-ocean ridges a
mid-ocean ridge is an underwater mountain system that is formed by plate
tectonics each year the ocean floor is known to spread one to two inches a rare
phenomenon that can catch you by surprise
if you are near a volcano is a geyser a geyser is a vent on the Earth’s surface
that lets out a forceful jet of water into the air Old Faithful is a geyser
located in Yellowstone National Park in Wyoming and it erupts every forty five
to a hundred and twenty-five minutes whether inside or on the surface the
earth is vibrating with natural forces that can happen at any time to practice
what you’ve learned about earthquakes volcanoes and tsunamis be sure to play
our fun online games and quizzes until next time remember to always be clever

2 thoughts on “Earthquakes, Volcanoes, and Tsunamis

  1. thanks for another awesome video,I hope you will do more and more.

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