JPS58174882A - Earthquake discriminator - Google Patents

Abstract

PURPOSE:To prevent misdiscrimination by discriminating earthquake utilizing an acceleration component. CONSTITUTION:An incoming signal of an earthquake is differentiated with a differentiator 5. Then, an acceleration frequency component of an artificial earthquake is extracted with a filter 6 and an acceleration frequency component of an earthquake wave is extracted with a filter 7. Output of the filter 6 is integrated with an integration circuit 2 and inputted into a comparator 4 as reference voltage. The comparator 4 outputs a signal when the output of the filter 7 is larger than the output of the integrator 2. This output is utilized as such for discrimination of earthquake.

Description

[Detailed Description of the Invention] (1) Technical Field of the Invention The present invention performs differential operation when performing all earthquake determination,
Related to a 4'lJ constant device that prevents erroneous judgments due to noise.

(2) Prior art and its problems As shown in Figure 1, the conventional earthquake determination device inputs the ground motion velocity signal from the seismograph to a filter 1, removes low frequency components and high frequency components, and integrates the ground motion velocity signal. They are respectively input to circuits 2 and 3.

Integral 1gIM2 has a long integration time constant of 100θθC, and as shown in FIG. 2(a), it constantly integrates the fine movement component.

On the other hand, the integration circuit 3 has an integration time constant of l 8e (!
Respond to short-term changes.

That is, as shown in FIG. 2(b), it responds to seismic waves whose amplitude changes rapidly.

The outputs of the integrating circuits 2 and 3 are input to the comparator output, and when the output of the integrating circuit 3 becomes larger than the output of the integrating circuit 2, a judgment output is obtained from the comparator number.

However, the above-mentioned apparatus sometimes makes erroneous determinations due to noise within the seismic wave frequency band.

(3) Purpose of the Invention The present invention has been made in view of the above points, and aims to provide an earthquake determination device that does not make false determinations due to noise within the seismic wave frequency band.

(4) Configuration of the invention: a differentiator that differentiates a velocity signal of ground motion; a first filter that extracts a frequency component due to noise in the output of the differentiator;
a second filter for extracting a frequency component caused by an earthquake; an integrating circuit for integrating the entire output of at least the second filter; and a comparison circuit for comparing the output of the integrating circuit and the output of the second filter to perform a ground comparison. This is accomplished by an earthquake determination device with

(5) Embodiment of the invention FIG. 2 is a diagram showing an embodiment of the invention, in which 5 is a differentiator and 6.7 is a filter.

In the present invention, the input ground motion velocity signal is differentiated using a total differentiator 5.

Looking at the output of the differentiator 5, the frequency characteristics of seismic waves and artificial noise are significantly different.

In other words, the period of an earthquake corresponds to the natural period of the ground through which waves propagate.

The predominant period is 01 to 04 seconds on hard ground, and 1 to 2 seconds on soft ground.

On the other hand, the period of artificial noise is about one order of magnitude shorter.
When differentiation is performed, characteristics as shown in FIG. 4 are output.

The filter 6 extracts all the acceleration frequency components of the artificial earthquake, and the filter 6 extracts all the acceleration frequency components of the seismic wave.

The output of the filter 6 is integrated by the integrating circuit 2 and inputted to the comparator number as a reference voltage.

The comparator number outputs a signal when the output of the filter becomes larger than the output of the integrator 2.

This output is used as an earthquake judgment output.

(6) Effect of invention It is possible to prevent a rice-like decision.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a conventional earthquake determination device, FIG. 2 is a diagram showing a constant tremor component and seismic wave waveform, FIG. 3 is a diagram showing an earthquake determination device according to the present invention, and FIG. 4 is a diagram showing details of the present invention. FIG. In the figure, 2 is an integrator, number is a comparator, 5 is a differentiator, and 6.1 is a filter. Figure 1 (Ill) Figure 2 1□-□]

Claims (1)

[Claims] a differentiator that calculates the ground motion velocity by 1 index; a first filter that removes all the frequency components due to noise in the output of the differentiator; a second filter that removes all the frequency components due to earthquakes; and at least the second filter. an integrating circuit that integrates the filter output of
An earthquake determination device having a comparison circuit for comparing an output of a d-integrator circuit and an output of a second filter to determine an earthquake.