Sissi Liu, ID: 260371961
The Great Invention: Seismoscope
Slide 3
The seismoscope is useful primarily as an alert system to let people know an
earthquake happened. More modern scientific equipment provides information about
the details and does not just signal to alert people to the occurrence of a quake. By
using a network of equipment to measure seismic activity, researchers can pinpoint
the epicenters of earthquakes, track earthquake activity, and learn more about the
origins of quakes. These devices are also useful for activities like issuing tsunami
warnings.
A seismometer (seismograph) is an instrument that measures motions of the ground.
Seismologists prefer to use seismometer rather than seismoscope, because the range
of data they can record provides much more informations about the earthquake. For
example, different type of seismic waves, distance from epicenter, magnitude of the
earthquake, etc.
Slide 4
According to "Han" records, it was a large vessel, about 2 meters in diameter, On the
outside of the vessel there were eight dragon heads, facing east, west, south, north,
northeast, southeast, southwest, and northwest directions. Each dragon's mouth
held a small copper ball. The mouth of each dragon crouching toward the ground
aligning a copper frog. When an earthquake occurred, the seismic waves will lead the
solid center stone to touch the lever, then the ball goes out of the dragon’s mouth and
naturally fall to the frog’s mouth. So that observers know what time and what
direction an earthquake occured.
Slide 5
The Chinese scientist Zhang Heng invented the earliest known seismoscope in 132
A.D. In 134 AD December 13, this instrument had detected its first ground motion at
western side of Luoyang (capital where Zhang Heng lived). However, due to people
did not feel the vibration, they refused to believe its capability of prediction, and tried
to discard it. A few days later, a messenger reported occurence of a large earthquake
in more than four-hundred-mile from the west of Luoyang. This makes both inside
and outside of the court to believe "all of its wonderful services."
Slide 6
- James David Forbes invented the seismometer in 1842.
- The first accurate seismograph in 1880 was invented by the British geographer John
Milne in Japan, he is also known as the "father of modern seismology." He invented a
variety of devices to detect seismic waves, one of which is a horizontal pendulum
seismic detector.