SU1436086A1 - Seismometer for powerful earthquakes - Google Patents

Abstract

The invention relates to seismometry, in particular, to devices for recording seismic vibrations with strong earthquakes. The purpose of the invention is to provide information and reliability of the seismograph. The device contains a seismograph triggering channel for strong earthquakes from an acoustic signal preceding tangible seismic vibrations. The acoustic channel consists of a series-connected sound receiver, filter, amplifier, Schmitt trigger, counter, and decoder. In addition, a toe input trigger trigger and a two-input time switch with variable delay are introduced into the seismograph. The acoustic channel starts a seismograph for registration with registration off. Rattor in 0.5-1.0 s. If a seismic signal arrives, the off delay is extended to 50-60 s, i.e. for the entire recording time of a close strong earthquake. The device allows to reduce the loss of information at the beginning of the recording of the earthquake while at the same time increasing the reliability of the seismograph. 1 il. 0 С

Description

This invention relates to seismometry, in particular, to devices for recording seismic vibrations during strong earthquakes.

The purpose of the invention is to increase the information content and reliability of the seismograph.

The drawing shows a block diagram of a strong earthquake seismograph.

following the included wobble oscillations.

When the acoustic signal arrives at the output of the sound receiver 3, for example, a geophone, an electrical signal arises. This signal is fed to the input of the low-pass filter 4. Filtered signals with frequencies up to 300

The seismograph contains at least | 0 500 Hz amplified by amplifier 5 and

re one accelerometer 1, seismic starter 2, sound receiver 3, low-pass filter 4, amplifier 5, Schmitt trigger 6, counter 7, decoder B, two-input time relay 9 with adjustable delay, three-input trigger 10 and recorder P.

Seismograph works as follows.

arrive at a Schmitt trigger input. When signals of a Schmitt trigger 6 are exceeded by a certain specified level, pulses are output at its output, which arrive at counter input 7, the output of which is connected to the decoder 8. After accumulation on the counter 7, 10-15 pulses corresponding to 10-15 per

In most cases, tangible co-20 ladies of an acoustic wave, a decoder 8

With the strongest and strongest earthquakes, the ground swan is prefigured by intense low-frequency oscillations (i) (hum), usually heard 0.1–1.5 s before the start of tangible seismic

ground vibrations. These acoustical: signals are used to turn on the recorder of a seismograph, operating in standby mode. To reduce the number I, false positives from acoustic noise I limit the use of acoustic signals used in the frequency range of 300–500 Hz in accordance with the expected spectrum of sound vibrations at the beginning of a strong earth meter.

For increased reliability, -. The seismograph from acoustic signals associated with strong earthquake, the seismograph should not react to pulsed acoustic interference, therefore, ensure the recorder is turned on only after passing, at a price of 10-15 periods of acoustic wave.

In addition, to improve the reliability of the seismograph, the recorder is turned off after 0.5-1.0 s in the event of false switching from acoustic interference, if after 0.1-0.5 s after the acoustic signal no noticeable seismic vibrations occur, and also, the recorder continued operation for 50-60 s, which corresponds to the duration of seismic oscillations with close strong earthquakes, in the case of the arrival of intense seismic vibrations.

arrive at the input of the Schmitt trigger 6. When signals at the output of the Schmitt trigger 6 are set to a certain level, pulses are generated at its output, which arrive at the input of counter 7, the output of which is connected to the decoder 8. After accumulation on the counter 7, 10-15 pulses corresponding to 10-15 perio5

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Pushes 10 pulses into the first input of the trigger, cocking this trigger. At the output of the trigger 10, a signal occurs that includes the recorder 11, which starts recording signals from accelerometers 1. At the same time, the pulse from the output of the decoder 8 is fed to the first input of the time relay 9, providing a small delay of 0.5-1.0 s determined by the time interval 0.1– Os5 s between the arrival of an acoustic signal and the onset of perceptible seismic vibrations.

Further, the operation of the seismograph continues in one of two modes. If, after an interval of up to 0.5-1.0 s after turning on recorder 11, significant seismic oscillations arrive, an electrical signal is sent from the seismic starter 2 to the second time input 9, which changes the delay time relay 9 to 50-60 s, and the recorder 11 during this time records signals from accelerometers 1. After 50-60 seconds, the pulse from the output of the time relay resets the trigger 10 and the signal from its output registers 1 and 1 turns off.

If the switching on of recorder I1 is connected with acoustic noise, after c after switching on trigger 10, the output of time relay 9 generates a signal that resets trigger 10. Recorder P turns off.

The third mode of operation of the seismograph is realized in the event that the acoustic signal preceding the seismic vibrations is absent. In this case, with the arrival of seismic oscillations, the level of which crosses the threshold for triggering seismic starter 2, the signal from its code goes to the second input of the trigger 10 and simultaneously to the second input of the time relay 9. The trigger 10 is activated and the signal from its output turns on the recorder 11. The recording of signals from accelerometers 1 begins. After a time interval of 50-60 seconds, determined by the delay of the time relay 9, from its output to the third input of the trigger 10 a signal drops, and the recorder I turns off.

Claims (1)

Invention Formula Seismograph of strong earthquakes, containing at least one an accelerometer connected to the recorder and a seismic starter, characterized in that, in order to increase the information content and reliability of the seismograph, it additionally includes a sequentially connected sound receiver, filter, amplifier, Schmitt trigger, counter and decoder, as well as a three-input trigger and two-time relay with adjustable delay, while the output of the decoder is connected to the first input of the time relay and the first input of the trigger, to the second input of the trigger and the second input of the time relay is connected to the output of the seismic of the tarter, the output of the time relay is connected to the third trigger input, and the trigger output is connected to the recorder.