1345:(essentially a sound wave in rock) can be determined by sending packets in both directions in the looped pair of optical fibers; the difference in the arrival times of the first pair of perturbed packets indicates the distance along the cable. This point is also the point closest to the earthquake's epicenter, which should be on a plane perpendicular to the cable. The difference between the p-wave/s-wave arrival times provides a distance (under ideal conditions), constraining the epicenter to a circle. A second detection on a non-parallel cable is needed to resolve the ambiguity of the resulting solution. Additional observations constrain the location of the earthquake's epicenter, and may resolve the depth.
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seconds, or once per thirty seconds. The general-purpose instruments of small stations or amateurs usually oscillate once per ten seconds. A pan of oil is placed under the arm, and a small sheet of metal mounted on the underside of the arm drags in the oil to damp oscillations. The level of oil, position on the arm, and angle and size of sheet is adjusted until the damping is "critical", that is, almost having oscillation. The hinge is very low friction, often torsion wires, so the only friction is the internal friction of the wire. Small seismographs with low proof masses are placed in a vacuum to reduce disturbances from air currents.
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485:. The best mountings may be in deep boreholes, which avoid thermal effects, ground noise and tilting from weather and tides. Other instruments are often mounted in insulated enclosures on small buried piers of unreinforced concrete. Reinforcing rods and aggregates would distort the pier as the temperature changes. A site is always surveyed for ground noise with a temporary installation before pouring the pier and laying conduit. Originally, European seismographs were placed in a particular area after a destructive earthquake. Today, they are spread to provide appropriate coverage (in the case of
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1020:/m; local geologic seismographs, about 1,500 V/m; and teleseismographs, used for world survey, about 20,000 V/m. Instruments come in three main varieties: short period, long period and broadband. The short and long period measure velocity and are very sensitive, however they 'clip' the signal or go off-scale for ground motion that is strong enough to be felt by people. A 24-bit analog-to-digital conversion channel is commonplace. Practical devices are linear to roughly one part per million.
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systems, the light was reflected to a pair of differential electronic photosensors called a photomultiplier. The voltage generated in the photomultiplier was used to drive galvanometers which had a small mirror mounted on the axis. The moving reflected light beam would strike the surface of the turning drum, which was covered with photo-sensitive paper. The expense of developing photo-sensitive paper caused many seismic observatories to switch to ink or thermal-sensitive paper.
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that record data from up to 20 channels into a 16-mm film. The recorded film can be viewed by a machine. The reading and measuring from these types of media can be done by hand. After the digital processing has been used, the archives of the seismic data were recorded in magnetic tapes. Due to the deterioration of older magnetic tape medias, large number of waveforms from the archives are not recoverable.
674:, says that it was 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 dragons' 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
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geophones are sometimes used to perform three-dimensional reflective imaging of subsurface features. Basic linear refractive geomapping software (once a black art) is available off-the-shelf, running on laptop computers, using strings as small as three geophones. Some systems now come in an 18" (0.5 m) plastic field case with a computer, display and printer in the cover.
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recording system allowed for a continuous record, the first to do so. The first seismogram was recorded on 3 November 1880 on both of Ewing's instruments. Modern seismometers would eventually descend from these designs. Milne has been referred to as the 'Father of modern seismology' and his seismograph design has been called the first modern seismometer.
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sensitive instruments to ten seconds. The basic damped horizontal pendulum seismometer swings like the gate of a fence. A heavy weight is mounted on the point of a long (from 10 cm to several meters) triangle, hinged at its vertical edge. As the ground moves, the weight stays unmoving, swinging the "gate" on the hinge.
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unrolled behind a truck. Now most short-range systems use "thumpers" that hit the ground, and some small commercial systems have such good digital signal processing that a few sledgehammer strikes provide enough signal for short-distance refractive surveys. Exotic cross or two-dimensional arrays of
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One of the continuing problems with sensitive vertical seismographs is the buoyancy of their masses. The uneven changes in pressure caused by wind blowing on an open window can easily change the density of the air in a room enough to cause a vertical seismograph to show spurious signals. Therefore,
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Later, professional suites of instruments for the worldwide standard seismographic network had one set of instruments tuned to oscillate at fifteen seconds, and the other at ninety seconds, each set measuring in three directions. Amateurs or observatories with limited means tuned their smaller, less
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The first seismographs were invented in the 1870s and 1880s. The first seismograph was produced by
Filippo Cecchi in around 1875. A seismoscope would trigger the device to begin recording, and then a recording surface would produce a graphical illustration of the tremors automatically (a seismogram).
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in AD 143, 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
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Most instruments measure directly the ground motion using the distance sensor. The voltage generated in a sense coil on the mass by the magnet directly measures the instantaneous velocity of the ground. The current to the drive coil provides a sensitive, accurate measurement of the force between the
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expressed their dissatisfaction with the current available seismometers, still using the large 1842 Forbes device located in Comrie Parish Church, and requested a seismometer which was compact, easy to install and easy to read. In 1875 they settled on a large example of the Mallet device, consisting
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Prior to the availability of digital processing of seismic data in the late 1970s, the records were done in a few different forms on different types of media. A "Helicorder" drum was a device used to record data into photographic paper or in the form of paper and ink. A "Develocorder" was a machine
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Modern instruments use electronic sensors, amplifiers, and recording devices. Most are broadband covering a wide range of frequencies. Some seismometers can measure motions with frequencies from 500 Hz to 0.00118 Hz (1/500 = 0.002 seconds per cycle, to 1/0.00118 = 850 seconds per cycle).
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The advantage of a horizontal pendulum is that it achieves very low frequencies of oscillation in a compact instrument. The "gate" is slightly tilted, so the weight tends to slowly return to a central position. The pendulum is adjusted (before the damping is installed) to oscillate once per three
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Both accessed 2010-9-29 Morrissey was a professional seismographic instrument engineer. This superior design uses a zero-length spring to achieve a 60-second period, active feedback and a uniquely convenient variable reluctance differential transducer, with parts scavenged from a hardware store.
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Marra, Giuseppe; Clivati, Cecilia; Luckett, Richard; Tampellini, Anna; KronjÀger, Jochen; Wright, Louise; Mura, Alberto; Levi, Filippo; Robinson, Stephen; Xuereb, André; Baptie, Brian; Calonico, Davide (3 August 2016), "Ultrastable laser interferometry for earthquake detection with terrestrial and
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of various sizes installed at right angles to each other on a sand bed, where larger earthquakes would knock down larger pins. This device was constructed in 'Earthquake House' near Comrie, which can be considered the world's first purpose-built seismological observatory. As of 2013, no earthquake
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as wave sources. The first efforts at this method used manual data reduction from paper seismograph charts. Modern digital seismograph records are better adapted to direct computer use. With inexpensive seismometer designs and internet access, amateurs and small institutions have even formed a
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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. It presents the data in a standard digital
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Early seismometers had an arrangement of levers on jeweled bearings, to scratch smoked glass or paper. Later, mirrors reflected a light beam to a direct-recording plate or roll of photographic paper. Briefly, some designs returned to mechanical movements to save money. In mid-twentieth-century
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published an 1848 paper where he suggested ideas for seismometer design, suggesting that such a device would need to register time, record amplitudes horizontally and vertically, and ascertain direction. His suggested design was funded, and construction was attempted, but his final design did not
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in 1796, who improved upon
Salsano's pendulum instrument, using a pencil to mark, and using a hair attached to the mechanism to inhibit the motion of a clock's balance wheel. This meant that the clock would only start once an earthquake took place, allowing determination of the time of incidence.
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in response to an
Earthquake that took place on February 22, 1880, at Yokohama (Yokohama earthquake). Two instruments were constructed by Ewing over the next year, one being a common-pendulum seismometer and the other being the first seismometer using a damped horizontal pendulum. The innovative
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are often heavy cylindrical magnets with a spring-mounted coil inside. As the case moves, the coil tends to stay stationary, so the magnetic field cuts the wires, inducing current in the output wires. They receive frequencies from several hundred hertz down to 1 Hz. Some have electronic
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Today, the most common recorder is a computer with an analog-to-digital converter, a disk drive and an internet connection; for amateurs, a PC with a sound card and associated software is adequate. Most systems record continuously, but some record only when a signal is detected, as shown by a
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It might seem logical to make the heavy magnet serve as a mass, but that subjects the seismograph to errors when the Earth's magnetic field moves. This is also why seismograph's moving parts are constructed from a material that interacts minimally with magnetic fields. A seismograph is also
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A simple seismometer, sensitive to up-down motions of the Earth, is like a weight hanging from a spring, both suspended from a frame that moves along with any motion detected. The relative motion between the weight (called the mass) and the frame provides a measurement of the vertical
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Early seismometers used optical levers or mechanical linkages to amplify the small motions involved, recording on soot-covered paper or photographic paper. Modern instruments use electronics. In some systems, the mass is held nearly motionless relative to the frame by an electronic
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further developed this concept in 1751, having the pendulum create trace marks in sand under the mechanism, providing both magnitude and direction of motion. Neapolitan clockmaker
Domenico Salsano produced a similar pendulum which recorded using a paintbrush in 1783, labelling it a
1334:-scale changes in the length of the cable. As the length changes so does the time it takes a packet of light to traverse to the far end of the cable and back (using a second fiber). Using ultra-stable metrology-grade lasers, these extremely minute shifts of timing (on the order of
543:, though it is more applicable to the older instruments in which the measuring and recording of ground motion were combined, than to modern systems, in which these functions are separated. Both types provide a continuous record of ground motion; this record distinguishes them from
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described a seismoscope in 1703, which used a bowl filled with mercury which would spill into one of eight receivers equally spaced around the bowl, though there is no evidence that he actually constructed the device. A mercury seismoscope was constructed in 1784 or 1785 by
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Seismic observatories usually have instruments measuring three axes: north-south (y-axis), east-west (x-axis), and vertical (z-axis). If only one axis is measured, it is usually the vertical because it is less noisy and gives better records of some seismic waves.
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of a seismograph must be accurately characterized, so that its frequency response is known. This is often the crucial difference between professional and amateur instruments. Most are characterized on a variable frequency shaking table.
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In other systems the weight is allowed to move, and its motion produces an electrical charge in a coil attached to the mass which voltage moves through the magnetic field of a magnet attached to the frame. This design is often used in a
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in 1842, which recorded the measurements of seismic activity through the use of a pencil placed on paper above the pendulum. The designs provided did not prove effective, according to Milne's reports. It was Milne who coined the word
931:). While not sensitive enough to detect distant earthquakes, this instrument could indicate the direction of the pressure waves and thus help find the epicenter of a local quake. Such instruments were useful in the analysis of the
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algorithm called UrbanDenoiser which can detect earthquakes, particularly in urban cities. The algorithm filters out the background noise from the seismic noise gathered from busy cities in urban areas to detect earthquakes.
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This technique is expected to be a boon in observing earthquakes, especially the smaller ones, in vast portions of the global ocean where there are no seismometers, and at a cost much cheaper than ocean bottom seismometers.
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between 1848 and 1850, which used a point-suspended rigid cylindrical pendulum covered in paper, drawn upon by a fixed pencil. The cylinder was rotated every 24 hours, providing an approximate time for a given quake.
1006:, in which three identical motion sensors are set at the same angle to the vertical but 120 degrees apart on the horizontal. Vertical and horizontal motions can be computed from the outputs of the three sensors.
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most professional seismographs are sealed in rigid gas-tight enclosures. For example, this is why a common
Streckeisen model has a thick glass base that must be glued to its pier without bubbles in the glue.
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in 1841, to describe this instrument. In 1843, the first horizontal pendulum was used in a seismometer, reported by Milne (though it is unclear if he was the original inventor). After these inventions,
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This produced the first effective measurement of horizontal motion. Gray would produce the first reliable method for recording vertical motion, which produced the first effective 3-axis recordings.
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The hinges on a seismograph are usually patented, and by the time the patent has expired, the design has been improved. The most successful public domain designs use thin foil hinges in a clamp.
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later to give velocity and position. Strong-motion seismometers are not as sensitive to ground motions as teleseismic instruments but they stay on scale during the strongest seismic shaking.
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set up a network of pendulum earthquake detectors following the 1731 Puglia
Earthquake, where the amplitude was detected using a protractor to measure the swinging motion. Benedictine monk
1044:(cover removed). Two masses for x- and y-direction can be seen, the third one for z-direction is below. This model is a CMG-40TOBS, manufactured by GĂŒralp Systems Ltd and is part of the
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to detect the direction of an earthquake, where the lead fell into four bins arranged in a circle, to determine the quadrant of earthquake incidence. He completed the instrument in 1841.
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invented a precursor of seismometer, a vertical wooden poles connected with wooden gutters on the central axis functioned to fill water into a vessel until full to detect earthquakes.
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The concept of measuring the "shaking" of something means that the word "seismograph" might be used in a more general sense. For example, a monitoring station that tracks changes in
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applies a magnetic or electrostatic force to keep the mass nearly motionless. The voltage needed to produce this force is the output of the seismometer, which is recorded digitally.
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short-term increase in the variation of the signal, compared to its long-term average (which can vary slowly because of changes in seismic noise), also known as a STA/LTA trigger.
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open only one dragon's mouth. The first earthquake recorded by this seismoscope was supposedly "somewhere in the east". Days later, a rider from the east reported this earthquake.
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The mechanical suspension for horizontal instruments remains the garden-gate described above. Vertical instruments use some kind of constant-force suspension, such as the
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Seismometers unavoidably introduce some distortion into the signals they measure, but professionally designed systems have carefully characterized frequency transforms.
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Oldroyd, David; Amador, F.; KozĂĄk, Jan; Carneiro, Ana; Pinto, Manuel (2007-01-01). "The Study of
Earthquakes in the Hundred Years Following Lisbon Earthquake of 1755".
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experiments in
England observed noise with a wave-form resembling the seismic waves generated by earthquakes. This was found to match seismological observations of an
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A worldwide array of seismometers can actually image the interior of the Earth in wave-speed and transmissivity. This type of system uses events such as earthquakes,
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807:, influenced by Mallet's 1848 paper, invented a seismometer in 1856 that could record the time of an earthquake. This device used metallic pendulums which closed an
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Small seismic imaging systems are now sufficiently inexpensive to be used by civil engineers to survey foundation sites, locate bedrock, and find subsurface water.
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691:(founded 1259) in Persia, though it is unclear whether these were constructed independently or based on the first seismoscope. French physicist and priest
935:. Further analysis was performed in the 1980s, using these early recordings, enabling a more precise determination of the initial fault break location in
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Strain-beam accelerometers constructed as integrated circuits are too insensitive for geologic seismographs (2002), but are widely used in geophones.
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In most designs the electronics holds a mass motionless relative to the frame. This device is called a "force balance accelerometer". It measures
923:. The result is that the stylus scratched a pattern corresponding with the Earth's movement. This type of strong-motion seismometer recorded upon a
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The frequency transform is carefully designed, unlike most amateur instruments. Morrisey is deceased, but the site remains up as a public service.
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instead of velocity of ground movement. Basically, the distance between the mass and some part of the frame is measured very precisely, by a
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with vibration, which then powered an electromagnet to stop a clock. Palmieri seismometers were widely distributed and used for a long time.
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systems. These seismometers are often used as part of a large scale governmental or scientific project, but some organizations such as the
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Zollner described torsionally suspended horizontal pendulums as early as 1869, but developed them for gravimetry rather than seismometry.
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in order to produce better detection devices for earthquakes. The outcome of this was an inverted pendulum seismometer constructed by
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In the
Southern Sung dynasty, gift money for bestowing upon officials by the imperial court was wrapped in paper envelopes (chih pao)
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Basic horizontal-motion seismograph. The inertia of the round weight tends to hold the pen still while the base moves back and forth.
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1262:. The data reduction methods resemble those of computer-aided tomographic medical imaging X-ray machines (CAT-scans), or imaging
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However, the instrument was not sensitive enough, and the first seismogram produced by the instrument was in 1887, by which time
670:(translated as, "instrument for measuring the seasonal winds and the movements of the Earth"). The description we have, from the
593:, a Chinese mathematician and astronomer. The first Western description of the device comes from the French physicist and priest
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6.0 earthquake in Italy, ~1400 km away. Further experiments in
England, Italy, and with a submarine fiber optic cable to
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Ferrari, Graziano (1997-01-01). "Cultural and scientific value of seismology's heritage in Europe: why and how to preserve".
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fulfill his expectations and suffered from the same problems as the Forbes design, being inaccurate and not self-recording.
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728:. Naturalist Nicolo Zupo devised an instrument to detect electrical disturbances and earthquakes at the same time (1784).
700:, a copy of which can be found at the University Library in Bologna, and a further mercury seismoscope was constructed by
404:. The output of such a deviceâformerly recorded on paper (see picture) or film, now recorded and processed digitallyâis a
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sensitive to changes in temperature so many instruments are constructed from low expansion materials such as nonmagnetic
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Seismometer without housing; presented during a demonstration for children about earthquakes at Alfred Wegener Institute.
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Seismographic systems used for petroleum or other mineral exploration historically used an explosive and a wireline of
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mass and frame, thus measuring directly the ground's acceleration (using f=ma where f=force, m=mass, a=acceleration).
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had completely spilled over, and did not provide useful information. He therefore devised a portable device that used
443:. A rotating drum is attached to the frame and a pen is attached to the weight, thus recording any ground motion in a
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1133:. The data from such an instrument is essential to understand how an earthquake affects man-made structures, through
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can also be used to precisely locate, in three dimensions, the source of an earthquake, using the time it takes for
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1258:, an array of seismometers image sub-surface features. The data are reduced to images using algorithms similar to
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also built a seismological tool of unknown design or efficacy (known as an earthquake machine) in the late 1790s.
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Some other sensitive designs measure the current generated by the flow of a non-corrosive ionic fluid through an
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damping, a low-budget way to get some of the performance of the closed-loop wide-band geologic seismographs.
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Earthquake Locations Determined by the Southern Alaska Seismograph Network for October 1971 through May 1989
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After World War II, the seismometers developed by Milne, Ewing and Gray were adapted into the widely used
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is a free tool for recent Macintosh laptop computers that implements a real-time three-axis seismograph.
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has been large enough to cause any of the cylinders to fall in either the original device or replicas.
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Science and Civilization in China, Volume 3: Mathematics and the Sciences of the Heavens and the Earth
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The foundation of a seismic station is critical. A professional station is sometimes mounted on
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The first moderately successful device for detecting the time of an earthquake was devised by
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discusses the history of development of the primary technology in global earthquake research.
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2039:. In Beer, Michael; Kougioumtzoglou, Ioannis A.; Patelli, Edoardo; Siu-Kui Au, Ivan (eds.).
1969:
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2239:"Toward improved urban earthquake monitoring through deep-learning-based noise suppression"
1090:. One of the amplified currents from the negative feedback loop drives a coil very like a
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is said to have invented the first seismoscope (by the definition above), which was called
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Fogleman, Kent A.; Lahr, John C.; Stephens, Christopher D.; Page, Robert A. (June 1993).
1251:, can use residential size detectors built into computers to detect earthquakes as well.
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Any movement from the ground moves the frame. The mass tends not to move because of its
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Sleeswyk AW, Sivin N (1983). "Dragons and toads: the Chinese seismoscope of BC. 132".
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William H.K. Lee; Paul Jennings; Carl Kisslinger; Hiroo Kanamori (27 September 2002).
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The Development Of Very-Broad-Band Seismography: Quanterra And The Iris Collaboration
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lander, the first time a seismometer was placed onto the surface of another planet.
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The first seismometer was made in China during the 2nd century. It was invented by
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Seismometers, seismographs, seismograms â what's the difference? How do they work?
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Yang, Lei; Liu, Xin; Zhu, Weiqiang; Zhao, Liang; Beroza, Gregory C. (2022-04-15).
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in Japan, from 1880 to 1895. Milne, Ewing and Gray, all having been hired by the
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400:. They are usually combined with a timing device and a recording device to form a
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1060:. As the earth moves, the electronics attempt to hold the mass steady through a
2303:"A deep-learning algorithm could detect earthquakes by filtering out city noise"
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In 1880, the first horizontal pendulum seismometer was developed by the team of
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A strong-motion seismometer measures acceleration. This can be mathematically
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to provide a long period (high sensitivity). Some modern instruments use a
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detected additional earthquakes, including one 4,100 km away, and an
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circuit. The amount of force necessary to achieve this is then recorded.
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Pendulum devices were developing at the same time. Neapolitan naturalist
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Another type of seismometer is a digital strong-motion seismometer, or
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Historical Encyclopedia of Natural and Mathematical Sciences, Volume 1
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An early special-purpose seismometer consisted of a large, stationary
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1824:"The invention of the Seismoscope | The Asian Age Online, Bangladesh"
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Seismometers were placed on the Moon starting in 1969 as part of the
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2139:"A Biography of Lucien LaCoste, inventor of the zero-length spring"
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in 1703. The modern seismometer was developed in the 19th century.
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that responds to ground displacement and shaking such as caused by
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The modern broadband seismograph can record a very broad range of
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in 1841, to describe an instrument designed by Scottish physicist
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Sean Morrisey's professional design of an amateur teleseismograph
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International Handbook of Earthquake & Engineering Seismology
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International Handbook of Earthquake & Engineering Seismology
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Strong motion sensors are used for intensity meter applications.
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Instrument that records seismic waves by measuring ground motions
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A new technique for detecting earthquakes has been found, using
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605:
1235:). Interconnected seismometers are also used, as part of the
578:
1803:. Cambridge: Cambridge University Press. pp. 626â635.
1478:
Agnew, Duncan Carr (2003). "Ch. 1: History of Seismology".
550:
The technical discipline concerning such devices is called
1341:
The point of the cable first disturbed by an earthquake's
687:
By the 13th century, seismographic devices existed in the
1511:
Erhard Wielandt's 'Seismic Sensors and their Calibration'
1301:
cables. In 2016 a team of metrologists running frequency
2382:
The Lehman amateur seismograph, from Scientific American
2164:
1917:
Shelley Unbound: Discovering Frankenstein's True Creator
1520:- Current (2002) reference by a widely consulted expert.
973:
Simplified LaCoste suspension using a zero-length spring
915:
started to move, the heavy mass of the pendulum had the
1094:. The result is that the mass stays nearly motionless.
604:. In December 2018, a seismometer was deployed on the
1737:
Science and Civilisation in China: Paper and Printing
939:
and its subsequent progression, mostly to the south.
739:
After an earthquake taking place on October 4, 1834,
1862:
Journal of the History of the Earth Sciences Society
2333:. Seismological Laboratory, Caltech. Archived from
1538:
Earthquakes and Engineers: an International History
2328:"NEWS FLASH!! SCSN Earthquake Catalog Completed!!"
1320:
848:Milne horizontal pendulum seismometer. One of the
814:By 1872, a committee in the United Kingdom led by
2114:"Physics of the Zero-Length Spring of Geoscience"
1012:Modern sensitivities come in three broad ranges:
2078:Herbert-Gustar, A. L.; Nott, Patrick A. (1980).
1773:"NASA's InSight Places First Instrument on Mars"
1771:Cook, Jia-Rui; Good, Andrew (19 December 2018).
1330:Seismic waves are detectable because they cause
1184:Seismometer in operation recording a seismogram.
1167:A Kinemetrics seismograph, formerly used by the
474:, which is used in exploration for oil and gas.
2043:. Berlin, Heidelberg: Springer. pp. 1â31.
1327:3.4 earthquake 89 km away from the cable.
410:. Such data is used to locate and characterize
743:observed that the mercury seismoscope held at
724:, possibly the first use of a similar word to
2080:John Milne : father of modern seismology
1564:
1562:
1357:Researchers at Stanford University created a
888:in the previous five years to assist Japan's
361:
8:
1541:. Reston, VA: ASCE Press. pp. 122â125.
1530:
1528:
1526:
759:In response to a series of earthquakes near
1740:. Cambridge University Press. p. 122.
2391:- not designed for calibrated measurement.
1855:
1853:
1851:
1849:
1847:
1845:
1843:
1729:
1727:
998:suspension. The LaCoste suspension uses a
509:, a shaking or quake, from the verb ÏΔίÏ,
368:
354:
37:
2278:
2210:
2200:
2030:
2028:
2026:
1973:
1943:
1941:
1939:
1937:
1307:
2232:
2230:
1169:United States Department of the Interior
1073:linear variable differential transformer
602:Apollo Lunar Surface Experiments Package
489:) or concentrated in high-risk regions (
29:
1705:
1703:
1470:
1203:sponge or a conductive fluid through a
837:had already demonstrated his design in
767:in 1839, a committee was formed in the
49:
2041:Encyclopedia of Earthquake Engineering
1082:That measurement is then amplified by
1077:linear variable differential capacitor
981:CMG-40T triaxial broadband seismometer
850:Important Cultural Properties of Japan
2157:"Redwood City Public Seismic Network"
854:National Museum of Nature and Science
539:, to draw. It is often used to mean
7:
1382:Matsushiro Seismological Observatory
1046:Monterey Accelerated Research System
1882:10.17704/eshi.26.2.h9v2708334745978
1482:. Vol. Part A. pp. 3â11.
1086:attached to parts of an electronic
1954:Bulletin of Earthquake Engineering
1293:Fiber optic cables as seismometers
25:
2377:The history of early seismometers
1950:"A history of British seismology"
1897:Cah. Cent. Europ. Geodyn. Seismol
1624:. Academic Press. pp. 283â.
1445:Pacific Northwest Seismic Network
775:, first presented in a report by
755:Early Modern designs (1839â1880)
672:History of the Later Han Dynasty
517:, to measure, and was coined by
57:
2094:"Who Invented the Seismograph?"
2049:10.1007/978-3-642-36197-5_171-1
1948:Musson, R. M. W. (2013-06-01).
1237:International Monitoring System
1004:"triaxial" or "Galperin" design
2446:â How Does A Seismometer Work?
2398:Also see Keith Payea's version
1607:. San Francisco: W.H. Freeman.
1374:Viewing of a Develocorder film
1278:"public seismograph network".
894:Seismological Society of Japan
828:The first seismographs (1880-)
1:
1914:Hart, Scott de (2013-07-22).
933:1906 San Francisco earthquake
796:constructed a seismometer in
2428:Hawaiian Volcano Observatory
1040:A low-frequency 3-direction
577:studies the "quakes" on the
1920:. Feral House. p. 39.
1535:Reitherman, Robert (2012).
1420:Galitzine, Boris Borisovich
1338:) appear as phase-changes.
1243:explosions, as well as for
1223:to propagate away from the
1211:Interconnected seismometers
882:foreign-government advisors
819:of an array of cylindrical
531:is another Greek term from
2497:
2440:â Research References 2012
2434:â retrieved on 2009-06-15.
1575:. Springer. p. 2657.
1393:
1227:, the initiating point of
1125:Strong-motion seismometers
1116:Another issue is that the
639:List of Chinese inventions
636:
501:The word derives from the
266:Coordinating Committee for
2326:Hutton, Kate; Yu, Ellen.
1975:10.1007/s10518-013-9444-5
1687:solar-center.stanford.edu
1460:Wood-Anderson seismometer
1215:Seismometers spaced in a
1075:. Some instruments use a
1024:format (often "SE2" over
919:to stay still within the
683:Early designs (1259â1839)
297:AdamsâWilliamson equation
2037:"Historical Seismometer"
1799:Needham, Joseph (1959).
1569:Ben-Menahem, A. (2009).
1245:Earthquake early warning
1042:ocean-bottom seismometer
513:, to shake; and ÎŒÎÏÏÎżÎœ,
491:strong-motion seismology
245:Seismic intensity scales
240:Seismic magnitude scales
2202:10.1126/science.aat4458
1734:Joseph Needham (1985).
959:Press-Ewing seismometer
911:on the bottom. As the
34:Kinemetric seismograph.
2481:Seismology instruments
2263:10.1126/sciadv.abl3564
2035:BatllĂł, Josep (2021).
1603:Richter, C.F. (1958).
1391:
1383:
1375:
1239:to detect underground
1185:
1172:
1143:engineering seismology
1135:earthquake engineering
1088:negative feedback loop
1049:
990:
982:
974:
865:
649:Amenhotep, son of Hapu
634:
487:weak-motion seismology
460:negative feedback loop
435:
307:Earthquake engineering
35:
2476:Measuring instruments
2307:MIT Technology Review
1822:Szczepanski, Kallie.
1605:Elementary Seismology
1455:Quake-Catcher Network
1394:Further information:
1389:
1381:
1373:
1256:reflection seismology
1249:Quake-Catcher Network
1183:
1166:
1084:electronic amplifiers
1039:
988:
980:
972:
892:efforts, founded the
847:
625:
433:
330:Earth Sciences Portal
302:FlinnâEngdahl regions
268:Earthquake Prediction
33:
2424:Video of seismograph
1653:"The RF Seismograph"
693:Jean de Hautefeuille
689:Maragheh observatory
595:Jean de Hautefeuille
292:Shear wave splitting
2255:2022SciA....8L3564Y
2187:submarine cables",
1966:2013BuEE...11..715M
1874:2007ESHis..26..321O
1809:1959scc3.book.....N
1233:Earthquake location
1188:Accelerographs and
927:(glass with carbon
414:, and to study the
192:Epicentral distance
2471:Chinese inventions
2466:1880 introductions
2416:2016-08-10 at the
2387:2009-02-04 at the
2145:on March 20, 2007.
2118:physics.mercer.edu
1663:on 1 December 2017
1516:2010-09-24 at the
1392:
1390:A Seismogram graph
1384:
1376:
1275:nuclear explosions
1231:rupture (See also
1186:
1173:
1050:
1000:zero-length spring
991:
983:
975:
965:Modern instruments
874:James Alfred Ewing
866:
773:James David Forbes
745:Bologna University
733:Ascanio Filomarino
702:NiccolĂČ Cacciatore
635:
569:waves presents an
523:James David Forbes
436:
416:internal structure
394:volcanic eruptions
169:Induced seismicity
116:Remotely triggered
36:
2195:(6401): 486â490,
2058:978-3-642-36197-5
1927:978-1-936239-64-1
1747:978-0-521-08690-5
1683:"The Singing Sun"
1631:978-0-08-048922-3
1582:978-3-540-68831-0
1548:978-0-7844-1071-4
1489:978-0-12-440652-0
1181:
1118:transfer function
852:. Exhibit in the
668:Houfeng Didong Yi
632:Houfeng Didong Yi
378:
377:
16:(Redirected from
2488:
2365:
2364:
2356:
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2332:
2323:
2317:
2316:
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2313:
2299:
2293:
2292:
2282:
2249:(15): eabl3564.
2243:Science Advances
2234:
2225:
2223:
2214:
2204:
2183:
2177:
2176:
2174:
2172:
2167:on 26 March 2018
2163:. Archived from
2153:
2147:
2146:
2141:. Archived from
2135:
2129:
2128:
2126:
2124:
2110:
2104:
2103:
2101:
2100:
2090:
2084:
2083:
2075:
2069:
2068:
2066:
2065:
2032:
2021:
2020:
2018:
2017:
2008:. Archived from
2002:
1996:
1995:
1977:
1945:
1932:
1931:
1911:
1905:
1904:
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1659:. Archived from
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1615:
1609:
1608:
1600:
1594:
1593:
1591:
1589:
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1556:
1551:. Archived from
1532:
1521:
1508:
1502:
1501:
1475:
1325:
1312:
1182:
1032:Teleseismometers
886:Meiji Government
880:, who worked as
809:electric circuit
777:David Milne-Home
698:Atanasio Cavalli
565:noise affecting
519:David Milne-Home
426:Basic principles
370:
363:
356:
141:Earthquake swarm
61:
38:
21:
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2418:Wayback Machine
2389:Wayback Machine
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2363:(Report). USGS.
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2340:on 14 July 2014
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2013:
2006:"Seismographen"
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630:'s seismoscope
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575:helioseismology
563:electromagnetic
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2010:the original
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1661:the original
1657:www.nsarc.ca
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1571:
1553:the original
1537:
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1430:Inge Lehmann
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1336:femtoseconds
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1241:nuclear test
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1081:
1069:acceleration
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1051:
1022:
1016:, 50 to 750
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949:
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941:
937:Marin county
925:smoked glass
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741:Luigi Pagani
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497:Nomenclature
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286:Other topics
234:
91:Blind thrust
18:Seismographs
2438:Seismoscope
2212:11696/59747
1784:20 December
1299:fiber optic
1159:Other forms
1092:loudspeaker
1058:electronics
1054:frequencies
878:Thomas Gray
816:James Bryce
782:seismometer
726:seismometer
717:Andrea Bina
664:Han dynasty
662:of China's
626:Replica of
618:Ancient era
606:planet Mars
552:seismometry
541:seismometer
535:and ÎłÏÎŹÏÏ,
529:Seismograph
412:earthquakes
402:seismograph
382:seismometer
274:Forecasting
235:Seismometer
229:Measurement
202:Shadow zone
51:Earthquakes
2460:Categories
2312:2022-04-17
2099:2022-10-12
2064:2022-10-17
2016:2011-02-18
1833:2022-10-12
1498:2002103787
1466:References
1440:John Milne
1396:Seismogram
1332:micrometer
1260:tomography
1225:hypocenter
1150:integrated
1141:, through
870:John Milne
835:John Milne
794:Karl Kreil
706:James Lind
660:Zhang Heng
637:See also:
628:Zhang Heng
591:Zhang Heng
556:seismology
445:seismogram
407:seismogram
398:explosions
386:instrument
317:Seismology
258:Prediction
197:Hypocenter
131:Supershear
111:Megathrust
106:Intraplate
101:Interplate
86:Aftershock
2271:2375-2548
1992:110740854
1984:1573-1456
1588:28 August
1366:Recording
1303:metrology
1283:geophones
1190:geophones
1014:geophones
907:, with a
749:lead shot
704:in 1818.
505:ÏΔÎčÏÎŒÏÏ,
187:Epicenter
164:Volcanism
126:Submarine
81:Foreshock
76:Mainshock
2444:Iris EDU
2414:Archived
2385:Archived
2289:35417238
2221:29903881
2171:28 March
2123:28 March
1753:16 April
1692:28 March
1667:28 March
1637:29 April
1514:Archived
1425:Geophone
1409:See also
1201:electret
1062:feedback
1026:Ethernet
905:pendulum
765:Scotland
472:geophone
337:Category
312:Seismite
43:a series
41:Part of
2405:SeisMac
2280:9007499
2251:Bibcode
2189:Science
1962:Bibcode
1903:: 1â21.
1870:Bibcode
1805:Bibcode
1720:: 1â19.
996:LaCoste
917:inertia
611:InSight
608:by the
585:History
573:. And
533:seismĂłs
507:seismĂłs
483:bedrock
452:inertia
136:Tsunami
96:Doublet
2452:â USGS
2432:Flickr
2344:4 July
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2055:
1990:
1982:
1924:
1744:
1628:
1579:
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1343:p-wave
1264:sonars
909:stylus
798:Prague
761:Comrie
656:AD 132
537:grĂĄphĆ
515:métron
396:, and
390:quakes
384:is an
217:S wave
212:P wave
153:Causes
2430:â on
2338:(PDF)
2331:(PDF)
1988:S2CID
1316:Malta
1229:fault
1108:invar
921:frame
913:earth
862:Japan
858:Tokyo
839:Japan
676:Gansu
503:Greek
420:Earth
69:Types
2346:2014
2285:PMID
2267:ISSN
2217:PMID
2173:2018
2125:2018
2053:ISBN
1980:ISSN
1922:ISBN
1786:2018
1778:NASA
1755:2013
1742:ISBN
1694:2018
1669:2018
1639:2013
1626:ISBN
1590:2012
1577:ISBN
1543:ISBN
1494:LCCN
1484:ISBN
929:soot
876:and
821:pins
511:seĂĆ
121:Slow
2426:at
2275:PMC
2259:doi
2207:hdl
2197:doi
2193:361
2045:doi
1970:doi
1878:doi
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