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Seismographs are instruments used to record the motion of the ground during an earthquake. As the seismograph shakes under the mass, the recording device on the mass records the relative motion between itself and the rest of the instrument, thus recording the ground motion.
How does a seismograph detect and record seismic waves?
In a seismometer, the fixed object consists of a mass suspended on springs within a case. During an earthquake, the mass remains still while the case around it moves with the ground shaking. Long period seismographs respond to lower frequency waves and are used to record distant events.
How are earthquakes recorded and detected?
Earthquakes are recorded by a seismographic network. Each seismic station in the network measures the movement of the ground at that site. The Richter scale measures the largest wiggle (amplitude) on the recording, but other magnitude scales measure different parts of the earthquake.
How does seismograph measure the magnitude of earthquake?
The Richter magnitude of an earthquake is determined from the logarithm of the amplitude of waves recorded by seismographs. First the seismic moment is computed, and then it is converted to a magnitude designed to be roughly equal to the Richter Scale in the magnitude range where they overlap.
How do you monitor earthquakes?
Seismometers allow us to detect and measure earthquakes by converting vibrations due to seismic waves into electrical signals, which we can then display as seismograms on a computer screen. Seismologists study earthquakes and can use this data to determine where and how big a particular earthquake is.
How does seismograph look like?
When you look at a seismogram, there will be wiggly lines all across it. These are all the seismic waves that the seismograph has recorded. Most of these waves were so small that nobody felt them. Because P waves are the fastest seismic waves, they will usually be the first ones that your seismograph records.
When a strong earthquake occurs What type of waves are recorded by the seismograph?
The two general types of vibrations produced by earthquakes are surface waves, which travel along the Earth’s surface, and body waves, which travel through the Earth. Surface waves usually have the strongest vibrations and probably cause most of the damage done by earthquakes.
How are earthquakes measured ks2?
Scientists use seismic waves to measure how big an earthquake is. They use a device called a seismograph to measure the size of the waves. To tell the strength of an earthquake scientists use a scale called the Moment Magnitude Scale or MMS (it used to be called the Richter scale).
Which seismic waves arrive first at a seismograph station?
The P wave is designated the primary preliminary wave because it is the first to arrive at a seismic station after an earthquake.
How do we measure the strength of an earthquake using intensity and magnitude?
The Richter scale measures the magnitude of earthquakes, and the Mercalli scale measures their intensity. The violence of seismic shaking varies considerably over a single affected area.
What is seismograph and seismogram?
seismograph, instrument that makes a record of seismic waves caused by an earthquake, explosion, or other Earth-shaking phenomenon. A record produced by a seismograph on a display screen or paper printout is called a seismogram.
How do you make a simple seismograph?
Stand the box up on one of the smaller sides. Carefully poke two holes opposite from each other near the rim of the cup. Tie a piece of string (slightly longer than the length of the box) to each hole. Carefully poke two holes in the top of the box (make them the same distance apart as the holes in the cup).
How does seismograph and accelerometer record earthquake?
Seismometers and accelerometers Accelerometers record the high accelerations from high frequency motion of nearby small earthquakes very well. With accurate timing, accelerograms can be used for source, path and site studies. This means that accelerometers are very useful for epicentral studies.
What is the graphical record of an earthquake?
A seismograph is the primary earthquake measuring instrument. The seismograph produces a digital graphic recording of the ground motion caused by the seismic waves. The digital recording is called a seismogram.
Is seismograph analog computer?
Delivered seismometers come with two styles of output: analog and digital. Analog seismographs require analog recording equipment, possibly including an analog-to-digital converter. The output of a digital seismograph can be simply input to a computer.
How was the seismograph invented?
In the modern world, John Milne invented the first seismograph in 1880. This seismograph detected earthquakes through a long pendulum that was attached to a stylus. When the earth shook, the stylus then wrote on a carbon-coated paper. This produced a pattern that detected the direction and intensity of the quake.
Why is a seismograph important?
Seismographs can detect quakes that are too small for humans to feel. During an earthquake, ground-shaking seismic waves radiate outward from the quake source, called the epicenter. These measurements allow scientists to estimate the distance, direction, magnitude, and the type of earthquake that just occurred.
How do seismograph stations help determine an earthquake’s epicenter?
Scientists use triangulation to find the epicenter of an earthquake. To determine the direction each wave traveled, scientists draw circles around the seismograph locations. The radius of each circle equals the known distance to the epicenter. Where these three circles intersect is the epicenter.
How do earthquakes happen ks3?
An earthquake is a sudden shockwave caused by rocks being under stress from the movements of plates at plate boundaries. Eventually the stress in the rock builds up enough to deform and reach breaking point. At that point, the stored up energy is released in the form of shockwaves.
What is the Ring of Fire ks2?
The Ring of Fire is the geographical area around the edges of the Pacific Ocean. It is called so because it is shaped as a horseshoe and it has more exploding, active volcanoes and earthquakes than any place on the earth. 80% of the world’s earthquakes occur in this area.
Which wave arrives at a seismograph last?
The slowest waves, surface waves, arrive last. They travel only along the surface of the Earth. There are two types of surface waves: Love and Rayleigh waves.
