## Who invented the seismograph gaston yla agrupacion santa fe 2016

#

It was developed in 1931 by the American seismologists Harry Wood and Frank Neumann. This scale, composed of 12 increasing levels of intensity that range from imperceptible shaking to catastrophic destruction, is designated by Roman numerals. It does not have a mathematical basis; instead, it is an arbitrary ranking based on observed effects. Richter Magnitude Scale

The Richter Magnitude Scale was developed in 1935 by Charles F. Richter of the California Institute of Technology. On the Richter Scale, magnitude is expressed in whole numbers and decimal fractions. For example, a magnitude 5.3 might be computed for a moderate earthquake, and a strong earthquake might be rated as magnitude 6.3. Because of the logarithmic basis of the scale, each whole number increase in magnitude represents a tenfold increase in measured amplitude; as an estimate of energy, each whole number step in the magnitude scale corresponds to the release of about 31 times more energy than the amount associated with the preceding whole number value.

Seismic waves are the vibrations from earthquakes that travel through the Earth; they are recorded on instruments called seismographs. Seismographs record a zigzag trace that shows the varying amplitude of ground oscillations beneath the instrument. Sensitive seismographs, which greatly magnify these ground motions, can detect strong earthquakes from sources anywhere in the world. The time, location and magnitude of an earthquake can be determined from the data recorded by seismograph stations. The sensor part of a seismograph is referred to as the seismometer, the graphing capability was added as a later invention. Chang Heng’s Dragon Jar

Heng’s invention was called the dragon jar. The dragon jar was a cylindrical jar with eight dragonheads arranged around its brim; each dragon had a ball in its mouth. Around the foot of the jar were eight frogs, each directly under a dragonhead. When an earthquake happened a ball dropped from a dragon’s mouth and was caught by the frog’s mouth. Water & Mercury Seismometers

A few centuries later, devices using water movement and later mercury were developed in Italy. In 1855, Luigi Palmieri of Italy designed a mercury seismometer. Palmieri’s seismometer had U-shaped tubes filled with mercury and arranged along the compass points. When an earthquake happened, the mercury would move and make electrical contact that stopped a clock and started a recording drum on which the motion of a float on the surface of mercury was recorded. This was the first device that recorded the time of the earthquake and the intensity and duration of any movement. Modern Seismographs

John Milne was the English seismologist and geologist who invented the first modern seismograph and promoted the building of seismological stations. In 1880, Sir James Alfred Ewing, Thomas Gray and John Milne, all British scientists working in Japan, began to study earthquakes. They founded the Seismological Society of Japan and the society funded the invention of seismographs. Milne invented the horizontal pendulum seismograph in 1880.