Explanation
Text
Earthquake
1. Plate Tectonics (Tectonic Plate)
According
to the theory of Plate Tectonics, the outermost layer of our planet is made of
a thin slab and is relatively hard to move to each other. This movement occurs
continuously since the earth was created up to now. Theory of Plate Tectonics
emerged since the 1960s, and until now this theory has successfully explained
the various geological events such as earthquakes, tsunamis, and volcanic
eruption, and also about how the formation of mountains, continents, and
oceans.
The
tectonic plates are formed by the continental crust (continental crust) or
oceanic crust (oceanic crust), and the top of the rock layers of the mantle
(earth’s mantle). Continental crust and oceanic crust, along with the top layer
of the mantle is called the lithosphere. The density of the material in the
oceanic crust is higher than the density of the continental crust. Similarly,
elements of the substance in the oceanic crust (mafic) are heavier than the
elements in the continental crust (felsik).
Below
the lithosphere, there is a layer of molten rock called the asthenosphere.
Because the temperature and pressure in the asthenosphere layer is very high,
rocks move this layer to flow like a liquid (fluid).
The
lithosphere is broken into several tectonic plates intersect with each other.
Here are the names of tectonic plates on the earth, and its location can be
seen on the map Tectonics.
2. Mechanism Earthquake
Simply put the earthquake can be described as “broken”,
or because of their fault (also called fault or commonly referred to as “fault”
by the geologists). What is broken? Broken rock is rock layers that make up the
earth’s surface. Rock may indeed be layered and can be broken, even before it
broke bend (folding) first. Below are some pictures that show it turns out
there all around us even though we rarely notice.
Generally
there are three types of fractures or faults, according to the mechanism,
reverse fault (thrust fault or a reverse fault), horizontal fault or the fault
shear (strike-slip), and normal faults (normal fault). Broadly speaking,
earthquake occurs when rocks break, both the broken and rose, broken and
shifted, as well as fractures and falls.
Fault
occurs due to rock pressure or traction continuously. If the elasticity of the
rock is saturated, then the rock will fracture to release energy from the
pressure and pull. While receiving the pressure, the rock will bend and after
releasing the pressure the rock will return to its original shape, this is
known as “Elastic Rebound Theory”.
Thus,
this further explains why the track is a subduction zone earthquake belt, or a
place where the center of the quake. Subduction zone is a zone where the two
plates meet, then that is where the pressure continuously for millions of years
ago until now. At the time of pressure energy is getting bigger and elasticity
of the rock is saturated then it will be broken to release energy such
pressures, so the earthquake occurred “is NOT” because of the collision of two
plates like two cars colliding provenance far between then suddenly collide,
causing crash. It is the subduction zone earthquakes that occur due to the
interaction between the two plates push each other so as to accumulate
considerable energy, earthquake itself occurrs because of the condition of the
rock on the plates (crust) and / or the lithosphere is broken to release the
pressure energy that has accumulated there during the period of certain time.
The seismic energy release mechanism is also vary and still be an interesting
research for researchers in the field geosience and seismicity.
An
earthquake in the subduction zone in Indonesia can be a shallow earthquake
(shallow earthquake), secondary (intermediate earthquake), and in (deep
earthquake). What about the earthquakes on land ? The concept is basically the
same, it happens because of pressure or pull of the earth’s tectonic
conditions, geological conditions and morphological conditions.
Then
on land, land can emerge new fault-fault caused by the earthquake due to
tectonic and geological processes that lead to a new fault-fault (faults
quarter) if it is because of landslides (landslide) as well as a large volcanic
earthquakes or other geological processes.
How
to fault-fault existing in the mainland, such as the Sumatran fault which runs
long and is divided into several segments? For fault-fault existing in the
land, it will be a weak zone. The point is that the area will be earthquake
prone areas because the rock has been broken, so it can be shifted back when
under pressure or traction. Plus earthquake in the area of fault can be
triggered by another earthquake which gives sufficient pressure on the fault
line. Indonesian earthquake activity is one of the most steeper in the world.
In National Earthquake Center on the 3rd floor of the building operational BMG,
there can be seen a Seismotectonic map of Indonesia, which shows seismic
activity (earthquakes) in the region of Indonesia. It can be seen there that
Indonesia has a high vulnerability to earthquakes.
Resources:
http://www.caramudahbelajarbahasainggris.net/2016/12/contoh-explanation-text-earthquake-terbaru.html
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