Today's scientists understand earthquakes a lot better than we did even 50 years ago, but they still can't match the quake predicting prowess of the common toad, which can detect seismic activity days in advance of a quake. A 2010 study published in Journal of Zoology found that 96 percent of male toads in a population abandoned their breeding site five days before the earthquake that struck Italy, in 2009, about 46 miles (74 kilometers) away. Researchers aren't quite sure how the toads do this, but it's believed that they can detect subtle signs, such as the release of gases and charged particles, that may occur before a quake.
How Do Seismographs work?
The idea behind a seismograph is fairly simple. A basic seismograph includes a solid base and a heavy weight suspended from a spring over the base. A pen hangs from the weight and a rotating drum with paper sits below it on the base. The tip of the pen touches the drum. When the earth shakes from an earthquake, the drum rotates and the weighted pen moves back and forth due to the motion of seismic waves. The pen records the movement on the drum. The paper recording of an earthquake is called a seismogram. The most high-tech seismographs used by scientists studying earthquakes today are sophisticated and precise. They are based on the same concept as a basic, simple seismograph, but make use of electronics, magnets, and amplifiers in order to accurately and precisely measure the smallest ripples in the earth caused by earthquakes.
What Is A Seismograph
Earthquakes are fascinating and frightening at the same time. Have you ever wondered how scientists study these earth-shaking events? They use what's called a seismograph, also called a seismometer, which is an instrument that measures and records seismic waves that move through the earth as the result of an earthquake. A modern seismograph can help scientists detect earthquakes and measure several aspects of the event.
Scientists measure and record this data to learn more about earthquakes, tectonic plates, and Earth's layers. Earthquakes are difficult to predict, but scientists studying them hope to use seismographic measurements to be able to make more accurate predictions.
The Inventor Of the Seismographs
Zhang Heng from China, invented the first seismoscope , which was called Houfeng Didong Yi (translated as, "instrument for measuring the seasonal winds and the movements of the Earth"). A large bronze vessel, about 2 meters in diameter; at eight points around the top were dragon's heads holding bronze balls. When there was an earthquake, one of the mouths would open and drop its ball into a bronze toad at the base, making a sound and supposedly showing the direction of the earthquake. On at least one occasion, probably at the time of a large earthquake in Gansu , the seismoscope indicated an earthquake even though one was not felt. The available text says that inside the vessel was a central column that could move along eight tracks; this is thought to refer to a pendulum, though it is not known exactly how this was linked to a mechanism that would open only one dragon's mouth.
Here are some pictures relating to the seismograph