Earthquake sensor, earthquake detection method, and earthquake detection program

Abstract

This invention provides a seismic sensor, an earthquake detection method, and an earthquake detection program that can accurately determine whether detected vibrations are from an earthquake or noise. [Solution] The seismic sensor 10 includes an acceleration acquisition unit 21, a total speed change calculation unit 24, a total change variation determination unit 25, and an earthquake determination unit 26. The acceleration acquisition unit 21 acquires the acceleration of the vibration. The total speed change calculation unit 24 calculates the total speed change over a predetermined fixed interval based on the acceleration acquired by the acceleration acquisition unit 21. The total change variation determination unit 25 determines whether or not there is variation in the total speed change calculated by the total speed change calculation unit 24 in each of a plurality of predetermined fixed intervals. The earthquake determination unit 26 determines whether or not the vibration is an earthquake based on the determination result of the total change variation determination unit 25 regarding the presence or absence of variation.

Description

Technical Field

[0001] The present invention relates to a seismic sensor for detecting seismic motion, a seismic determination method, and a seismic determination program.

Background Art

[0002] In recent years, seismic sensors have been incorporated into gas meters, electricity meters, distribution boards, outlets, etc., and when seismic motion of a magnitude greater than a predetermined value (for example, seismic intensity 5 or higher) is detected, a cutoff signal for shutting off the supply of gas, electricity, etc. is output. For example, Patent Document 1 discloses a seismic sensor that outputs a cutoff signal when an index value indicating the scale of an earthquake in a seismic processing period after a determination period during the seismic processing period is greater than or equal to a threshold value, and determines the occurrence of an earthquake based on the acceleration measured during the seismic processing period. A continuous earthquake determination unit, and a cutoff determination unit that prevents a cutoff signal from being output regardless of the index value when the continuous earthquake determination unit determines that an earthquake has not occurred.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, the above conventional seismic sensors have the following problems. That is, in the seismic sensor disclosed in the above publication, if there is even a slight noise characteristic in the detected vibration, there is a risk of misjudging the vibration as noise. In addition, since the noise characteristics change depending on the device or installation environment to which the seismic sensor is attached, it is difficult to accurately detect noise, and there is also a risk of misjudging noise as an earthquake.

[0005] The object of the present invention is to provide a seismic sensor, an earthquake determination method, and an earthquake determination program that can accurately determine whether detected vibrations are earthquakes or noise. [Means for solving the problem]

[0006] The seismic sensor according to the first invention comprises an acceleration acquisition unit, a total velocity change calculation unit, a total change variation determination unit, and an earthquake determination unit. The acceleration acquisition unit acquires the acceleration of the vibration. The total velocity change calculation unit calculates the total velocity change over a predetermined fixed interval based on the acceleration acquired by the acceleration acquisition unit. The total change variation determination unit determines whether or not there is variation in the total velocity change calculated by the total velocity change calculation unit in each of a plurality of predetermined fixed intervals. The earthquake determination unit determines whether or not the vibration is an earthquake according to the determination result of the total change variation determination unit regarding the presence or absence of variation.

[0007] Here, to avoid misidentifying vibrations caused by factors other than earthquakes as earthquakes, for example, the system determines whether the detected vibration is an earthquake based on the results of a determination of whether there is variation in the total change in velocity over a certain period, which is calculated from the acceleration of the vibration. In this context, the seismic sensor is installed, for example, in energy measuring instruments such as gas and electricity meters, to shut off the energy supply when it detects an earthquake of a predetermined magnitude or higher.

[0008] The acceleration acquisition unit may be configured to directly measure the acceleration of vibrations applied to the seismic sensor, or it may be configured to acquire the measured acceleration. The total change in velocity over a predetermined fixed interval is the sum of the changes in velocity over a fixed interval calculated from the acceleration from the start to the end of the vibration, and is used to distinguish whether the vibration is caused by a force of approximately constant magnitude or by forces of various magnitudes specific to earthquakes.

[0009] Here, if the variation in the total change in velocity over a predetermined interval is smaller than a predetermined threshold, it is estimated that the vibration is being subjected to a nearly constant force, and therefore the detected vibration is estimated to be a vibration exhibiting noise characteristics. Conversely, if the variation in the total change in velocity over a predetermined interval exceeds a predetermined threshold, it is estimated that the vibrations are caused by forces of varying magnitudes characteristic of earthquakes being continuously applied, and therefore the detected vibrations are estimated to be vibrations that exhibit the characteristics of an earthquake. This allows the system to determine whether the detected vibration is an earthquake or noise based on the variation in the total change in velocity over a predetermined period, derived from the acceleration of the detected vibration. This makes it possible to detect vibrations where a nearly constant force is continuously applied as noise without misidentifying them as earthquakes. As a result, it is possible to accurately determine whether the detected vibration is from an earthquake or noise.

[0010] The seismic sensor according to the second invention is the same as the seismic sensor according to the first invention, wherein the total change in speed calculation unit calculates the total change in speed by integrating the absolute value of the acceleration over a certain interval. This allows for highly accurate determination of whether detected vibrations are earthquakes or noise, using the total change in velocity calculated by integrating the absolute value of acceleration over a certain interval.

[0011] The seismic sensor according to the third invention is a seismic sensor according to the first or second invention, wherein the earthquake determination unit determines that the vibration is noise when the total change variation determination unit determines that the variation is smaller than a predetermined threshold. This allows for accurate determination that detected vibrations are noise when the variation in the total velocity change is small, rather than exhibiting the earthquake characteristic of large variability in the total velocity change.

[0012] The seismic sensor according to the fourth invention is a seismic sensor according to the first or second invention, wherein the earthquake determination unit determines that the vibration is an earthquake when the total change variation determination unit determines that the variation is greater than or equal to a predetermined threshold. This allows for accurate determination of whether the detected vibrations are indeed earthquake vibrations, especially when they exhibit characteristics of earthquakes such as a large variation in the total change in velocity.

[0013] The fifth seismic sensor is a seismic sensor according to the first or second invention, further comprising an acceleration waveform generation unit that generates an acceleration waveform showing the relationship between the acceleration measured in the acceleration acquisition unit and the elapsed time. The total speed change calculation unit calculates the total speed change from the acceleration waveform generated in the acceleration waveform generation unit. This allows for highly accurate determination of whether detected vibrations are earthquakes or noise by using the acceleration waveform, which shows the relationship between acceleration measured in the acceleration acquisition unit and elapsed time, to calculate the variation in the total change in velocity.

[0014] The earthquake sensor according to the sixth invention is an earthquake sensor according to the first or second invention, further comprising an earthquake magnitude calculation unit that determines whether or not an earthquake is of a predetermined seismic intensity or higher when an earthquake is determined to be occurring in the earthquake determination unit. This allows for improved user safety, for example, by outputting a shutoff signal to stop energy supplies such as electricity and gas if an earthquake is determined to be of magnitude 5 or higher, potentially posing risks such as fire or gas leaks.

[0015] The seismic sensor according to the seventh invention is a seismic sensor according to the first or second invention, further comprising a startup determination unit that calculates the intensity of vibration from the measurement results in the acceleration acquisition unit and switches from a power-saving mode to a measurement mode which consumes more power than the power-saving mode if the intensity of vibration is greater than or equal to a predetermined magnitude. This allows for highly accurate earthquake detection while suppressing power consumption, by switching to a measurement mode that performs earthquake determination processing using the vibration acceleration waveform only when the detected vibration intensity is above a predetermined magnitude (for example, equivalent to seismic intensity 4).

[0016] The seismic sensor according to the eighth invention is the seismic sensor according to the first or second invention, and further includes an output control unit that outputs a predetermined signal when it is determined in the earthquake determination unit that an earthquake has occurred. Thereby, for example, at the time of an earthquake, a cutoff signal for stopping the supply of energy such as electricity or gas, a warning signal for notifying danger, etc. can be output from the output unit.

[0017] The seismic sensor according to the ninth invention is the seismic sensor according to the first or second invention, and further includes a storage unit that stores the determination results in the total change amount variation determination unit and the earthquake determination unit. Thereby, necessary information can be retrieved from the storage unit that stores each determination result, and the earthquake determination result, etc. can be displayed and notified.

[0018] The earthquake determination method according to the tenth invention acquires the acceleration of vibration, calculates the total speed change amount in a certain interval from the acceleration from the occurrence to the end of the acquired vibration, determines whether there is a variation in the calculated total speed change amount, and determines whether the vibration is an earthquake according to the determination result of whether there is a variation.

[0019] Here, for example, in order to avoid misjudging a case where the seismic sensor is swaying due to vibration other than an earthquake as an earthquake, according to the determination result of whether there is a variation in the total speed change amount in a certain interval calculated from the acceleration of the vibration, it is determined whether the detected vibration is an earthquake. Here, this seismic sensor is, for example, mounted on an energy measuring instrument such as a gas or electric meter, and is installed to stop the supply of energy when an earthquake of a predetermined seismic intensity or higher is detected.

[0020] The acquisition of acceleration may be configured to directly measure the acceleration of the vibration applied to the seismic sensor, or may be configured to acquire the measured acceleration. The total change in speed over a certain period is the sum of the changes in speed over a certain period calculated from the acceleration from the start to the end of the vibration generation, and is used to distinguish between vibrations to which a force of approximately constant magnitude is applied, or vibrations to which forces of various magnitudes peculiar to an earthquake are applied.

[0021] Here, when the variation in the total change in speed over a certain period is smaller than a predetermined threshold value, it is estimated that a vibration with a substantially constant force is continuously applied, and thus the detected vibration is estimated to be a vibration showing the characteristics of noise. Conversely, when the variation in the total change in speed over a certain period is greater than or equal to a predetermined threshold value, it is estimated that vibrations with various magnitudes of forces peculiar to an earthquake are continuously applied, and thus the detected vibration is estimated to be a vibration showing the characteristics of an earthquake. Thereby, by determining whether the detected vibration is an earthquake or noise according to the variation in the total change in speed over a certain period from the acceleration of the detected vibration, it is possible to detect as noise without misjudging a vibration to which a substantially constant force is continuously applied as an earthquake. As a result, it is possible to accurately determine whether the detected vibration is an earthquake or noise.

[0022] The earthquake determination program according to the 11th invention acquires the acceleration of a vibration, calculates the total change in speed over a certain period from the acceleration from the start to the end of the acquired vibration, determines whether there is a variation in the calculated total change in speed, and causes a computer to execute an earthquake determination method for determining whether the vibration is an earthquake according to the determination result of whether there is a variation.

[0023] Here, for example, in order to avoid misjudging as an earthquake a case where the seismic sensor is swaying due to vibrations other than an earthquake, etc., it is determined whether the detected vibration is an earthquake according to the determination result of whether there is a variation in the total change in speed over a certain period calculated from the acceleration of the vibration. Here, this seismic sensor is installed, for example, on an energy measuring instrument such as a gas or electric energy meter, and is installed to stop the energy supply when an earthquake of a predetermined seismic intensity or higher is detected.

[0024] The acquisition of acceleration may involve directly measuring the acceleration of vibrations applied to the seismic sensor, or it may involve acquiring the measured acceleration. The total change in velocity over a certain period is the sum of the changes in velocity over a certain period, calculated from the acceleration from the start to the end of the vibration. It is used to distinguish between vibrations caused by a force of approximately constant magnitude and vibrations caused by various magnitudes of forces, which are characteristic of earthquakes.

[0025] Here, if the variation in the total change in speed over a certain interval is smaller than a predetermined threshold, it is estimated that the vibration is being subjected to a nearly constant force, and therefore the detected vibration is estimated to be a vibration exhibiting noise characteristics. Conversely, if the variation in the total change in velocity over a certain period exceeds a predetermined threshold, it is estimated that the vibrations are caused by forces of varying magnitudes characteristic of earthquakes being continuously applied, and therefore the detected vibrations are estimated to be vibrations that exhibit the characteristics of an earthquake.

[0026] This allows the system to determine whether the detected vibration is an earthquake or noise based on the variation in the total change in velocity over a certain period, derived from the acceleration of the detected vibration. This makes it possible to detect vibrations where a nearly constant force is continuously applied as noise without misidentifying them as earthquakes. As a result, it is possible to accurately determine whether the detected vibration is from an earthquake or noise. [Effects of the Invention]

[0027] According to the seismic sensor of the present invention, it is possible to accurately determine whether the detected vibration is from an earthquake or noise. [Brief explanation of the drawing]

[0028] [Figure 1] A control block diagram showing the configuration of an earthquake sensor according to one embodiment of the present invention. [Figure 2] A functional block diagram generated within the seismic sensor shown in Figure 1. [Figure 3](a) is a graph showing the acceleration waveform of vibration detected by the seismic sensor in Figure 2. (b) is a graph showing the relationship between the absolute value of the acceleration in the acceleration waveform in (a) and the passage of time. [Figure 4] (a) is a graph showing the total change in velocity calculated from the acceleration of vibrations when the vibrations detected by the seismic sensor in Figure 2 are noise. (b) is a graph showing the total change in velocity calculated from the acceleration of vibrations when the vibrations detected by the seismic sensor in Figure 2 are earthquakes. [Figure 5] (a) and (b) are diagrams illustrating the calculation of the coefficient of variation used in earthquake assessment using the variability of the total change in velocity. [Figure 6] A flowchart showing the processing flow of the earthquake detection method performed by the seismic sensor in Figure 2. [Modes for carrying out the invention]

[0029] An earthquake sensor according to one embodiment of the present invention will be explained below using Figures 1 to 6. In this embodiment, unnecessary details may be omitted. For example, detailed explanations of already well-known matters or redundant explanations of substantially identical configurations may be omitted. This is to avoid the following explanation becoming unnecessarily verbose and to facilitate understanding for those skilled in the art. Furthermore, the applicant provides the accompanying drawings and the following description so that those skilled in the art may fully understand the present invention, and not intends to limit the subject matter described in the claims.

[0030] (1) Configuration of the seismic sensor 10 As shown in Figure 1, the seismic sensor 10 according to this embodiment includes an acceleration sensor 11, a controller 12, a memory 13, and an output unit 14.

[0031] The acceleration sensor 11 is, for example, an acceleration sensor using a piezoelectric element or an acceleration sensor that detects capacitance between electrodes. The acceleration measured (also called "sampling") by the acceleration sensor 11 is output to the controller 12. The controller 12 is, for example, a general-purpose integrated circuit that acquires acceleration measured by the acceleration sensor 11 at a predetermined period, and determines the occurrence of an earthquake and calculates an index value indicating the magnitude of the earthquake based on the acquired acceleration.

[0032] Furthermore, the controller 12 operates in different modes, such as active mode or sleep mode, depending on the situation. Sleep mode is a mode in which the controller 12 operates with limited functionality, such as stopping instruction execution while still accepting interrupts, or stopping the supply of the clock. In this sleep mode, power consumption can be reduced compared to active mode.

[0033] Active mode is a mode that performs processing to determine whether the detected vibration is an earthquake or noise, and calculates an index value indicating the magnitude of the earthquake. The functional blocks (see Figure 2) generated by the CPU within the seismic sensor 10 when it reads the earthquake judgment program stored in memory 13 will be described in detail later. Memory 13 is a temporary storage means such as RAM (Random Access Memory) or a non-volatile memory such as EPROM (Erasable Programmable Read Only Memory), and stores, for example, acceleration measured by the acceleration sensor 11 and thresholds used for earthquake detection.

[0034] The memory 13 may also be the memory built into the accelerometer 11 or the controller 12. The output unit 14 is, for example, an output terminal of the controller 12. When the controller 12 determines, for example, that an earthquake has occurred, it outputs information indicating the occurrence and magnitude of the earthquake to other devices via the output unit 14. Furthermore, when an earthquake of a predetermined magnitude or greater is detected, the output unit 14 outputs a shut-off signal to external devices to stop the supply of energy such as electricity or gas.

[0035] (2) Functional block of seismic sensor 10 As shown in Figure 2, the seismic sensor 10 includes an acceleration acquisition unit 21, an acceleration waveform generation unit 22, a vibration intensity classification and activation determination unit 23, a total speed change calculation unit 24, a total change variation determination unit 25, an earthquake determination unit 26, an earthquake magnitude calculation unit 27, an output control unit 28, and a storage unit 30. These functional blocks shown in Figure 2 are configured by the controller 12 receiving acceleration data acquired from the acceleration sensor 11 and reading the program stored in the memory 13.

[0036] The acceleration acquisition unit 21 acquires acceleration measurement data measured at a predetermined period by the acceleration sensor 11. Typically, the acceleration acquisition unit 21 acquires acceleration measurement data that is repeatedly measured at a relatively low speed (i.e., a relatively large measurement period). When performing acceleration sampling at such low speeds, the controller 12 basically operates in a low-power sleep mode (standby state or power-saving mode). In the standby state, the acceleration sensor 11 is in an operating state that performs sampling at a low speed, so the controller 12 operates in a sleep mode with limited functionality, thereby suppressing power consumption.

[0037] Furthermore, when the acceleration acquisition unit 21 acquires vibrations greater than a threshold preset in the memory unit 30, the acceleration sensor 11 repeatedly measures acceleration at a higher speed (i.e., with a relatively smaller period) than during low-speed sampling. In such high-speed sampling, the controller 12 operates in sleep mode or active mode. Furthermore, when the earthquake detection unit 26, etc., described later, performs processing, the controller 12 operates in active mode (measurement mode). The transition from power-saving mode to measurement mode is called activating the seismic sensor 10.

[0038] The measurement mode is an operating state that performs high-speed sampling. Therefore, the controller 12 may operate in a sleep mode with limited functionality, or in an active mode that allows it to operate with maximum computing power. In measurement mode, the sampling period is shortened, and the controller 12 switches from sleep mode to active mode, resulting in higher power consumption than in power-saving mode.

[0039] The acceleration waveform generation unit 22 generates an acceleration waveform (see Figure 3(a)) that shows the relationship between the acceleration measured by the acceleration acquisition unit 21 and the elapsed time. The vibration intensity classification and activation determination unit 23 is a function of the acceleration sensor 11, and compares the acceleration value acquired by the acceleration acquisition unit 21 with the activation threshold held in the memory unit 30. If the acceleration value exceeds the activation threshold, it switches from power saving mode to measurement mode (activates the seismic sensor 10).

[0040] Furthermore, the vibration intensity classification and activation determination unit 23 calculates the vibration intensity from the measurement results of the acceleration acquisition unit 21, and if the vibration intensity is greater than or equal to a predetermined magnitude, it switches from the power saving mode to the measurement mode, which consumes more power than the power saving mode (activates the controller 12). Here, the vibration intensity classification process performed by the vibration intensity classification and activation determination unit 23 is carried out by filtering the acceleration values ​​acquired by the acceleration acquisition unit 21. At this time, the filtered acceleration is stored in the storage unit 30.

[0041] The total speed change calculation unit 24 calculates the total speed change over a certain period from the acceleration measured by the acceleration acquisition unit 21 from the start to the end of the vibration. Specifically, the total speed change calculation unit 24 generates a waveform of the absolute value of acceleration (|a(t)|) shown in Figure 3(b) from the acceleration waveform shown in Figure 3(a) generated by the acceleration waveform generation unit 22, and integrates the absolute value of acceleration over a certain period to calculate the total speed change (Δv N Calculate ).

[0042] Total change in speed Δv N As shown in Figure 3(b), it is calculated by integrating the absolute value of acceleration over a fixed interval (for example, three intervals separated by dashed lines (if each interval is 1 second, then 3 seconds)). For example, if the detected vibration is noise, the total speed change calculated by the total speed change calculation unit 24 will have little variation and be an almost constant value, as shown in Figure 4(a).

[0043] This is presumed to represent a characteristic of noise: "vibration caused by a force of roughly the same magnitude being continuously applied." If the detected vibration is an earthquake, the total change in velocity calculated by the total change in velocity calculation unit 24 will have a large variation, as shown in Figure 4(b). This is presumed to mean "vibrations caused by forces of varying magnitudes being continuously applied," which is a characteristic of earthquakes.

[0044] The total change variation determination unit 25 determines whether or not there is variation in the total change in speed calculated by the total change in speed calculation unit 24. In this embodiment, the seismic sensor 10 calculates the coefficient of variation from the total change in speed over a certain period in the earthquake determination method described later, and determines whether it is an earthquake or noise. For example, for the eight intervals shown in Figure 5(a), the total change in speed Δv N (N=1,2,3,4,5,6,7,8) As shown in Figure 5(b), the total speed change calculation unit 24 calculates Δv N The results are calculated as =12,15,8,8,14,15,9,15.

[0045] If μ is the mean value, σ is the standard deviation, and CV is the coefficient of variation of the total change in speed, then the coefficient of variation CV is calculated using the following relationships (1), (2), and (3).

[0046]

number

[0047]

number

[0048]

number

[0049] The earthquake determination unit 26 determines whether the detected vibration is an earthquake or noise, based on the determination result of the total change variation determination unit 25 regarding the presence or absence of variation. Specifically, the earthquake determination unit 26 determines that the detected vibration is noise when the total change variation determination unit 25 determines that the variation is smaller than a predetermined threshold. On the other hand, the earthquake determination unit 26 determines that the detected vibration is an earthquake when the total change variation determination unit 25 determines that the variation is above a predetermined threshold.

[0050] The earthquake magnitude calculation unit 27 determines whether or not an earthquake is of a predetermined seismic intensity or higher when the earthquake determination unit 26 determines that an earthquake has occurred. Furthermore, the earthquake magnitude calculation unit 27, after determining that the detected vibration is an earthquake and starting to calculate an index indicating the magnitude of the earthquake, excludes vibrations that can be considered noise such as shocks when calculating the earthquake magnitude.

[0051] The output control unit 28 controls the output of a signal from the output unit 14, which outputs a predetermined signal, according to whether the magnitude of the earthquake calculated by the earthquake magnitude calculation unit 27 is equal to or greater than a predetermined seismic intensity. Here, the predetermined signals output from the output unit 14 include, for example, a shutoff signal that is transmitted to external equipment such as an electricity supply device or a gas supply device in order to stop the supply of energy such as electricity or gas. The memory unit 30 stores, for example, the acceleration data acquired by the acceleration acquisition unit 21, the judgment results from the total change amount floating determination unit 25 and the earthquake determination unit 26, and so on.

[0052] <Earthquake determination method> The earthquake detection method using the seismic sensor 10 of this embodiment can be explained as follows using the flowchart shown in Figure 6.

[0053] In other words, in step S11, the acceleration acquisition unit 21 of the seismic sensor 10 acquires the acceleration measured by the acceleration sensor 11. Next, in step S12, the acceleration waveform generation unit 22 generates an acceleration waveform from the acceleration acquired in step S11. Next, in step S13, the total speed change calculation unit 24 adds the absolute value of acceleration to the integrated value s(i) (i=0,1,2).

[0054] Next, in step S14, the total change variation determination unit 25 determines whether a certain amount of time (for example, 1 second) has elapsed. If a certain amount of time has elapsed, proceed to step S15; otherwise, return to step S11 and repeat the subsequent processing. Next, in step S15, since it was determined in step S14 that a certain amount of time had elapsed, the total change amount variation determination unit 25 buffers the sum of the accumulated values ​​s(0) to s(2) as the total change amount of speed over a certain interval.

[0055] Next, in step S16, the total change variation determination unit 25 sets i to i+1 and takes the remainder when divided by 3. Next, in step S17, s(i) is cleared to zero. Next, in step S18, the total change variation determination unit 25 determines whether the vibration determination has been completed.

[0056] If the vibration detection is completed at this point, proceed to step S19. If the vibration detection is not completed, return to step S11 and repeat the subsequent processing. Next, in step S19, since it was determined in step S18 that the vibration determination was completed, the total change amount variation determination unit 25 calculates the coefficient of variation from the total change amount of speed over the buffered fixed section.

[0057] Next, in step S20, the total change variation determination unit 25 determines whether the coefficient of variation calculated in step S19 is smaller than a predetermined threshold. If the coefficient of variation is less than a predetermined threshold, the process proceeds to step S21; if the coefficient of variation is greater than or equal to the predetermined threshold, the process proceeds to step S22. Next, in step S21, the earthquake determination unit 26 determines, based on the determination result in step S20, that the detected vibration is noise, and terminates the process. On the other hand, in step S22, the earthquake determination unit 26 determines, based on the determination result in step S20, that the detected vibration is an earthquake, and terminates the process.

[0058] <Key Features> The seismic sensor 10 of this embodiment includes an acceleration acquisition unit 21, a total speed change calculation unit 24, a total change variation determination unit 25, and an earthquake determination unit 26. The acceleration acquisition unit 21 acquires the acceleration of the vibration. The total speed change calculation unit 24 calculates the total speed change over a predetermined fixed interval based on the acceleration acquired by the acceleration acquisition unit 21. The total change variation determination unit 25 determines whether or not there is variation in the total speed change calculated by the total speed change calculation unit 24 in each of a plurality of predetermined fixed intervals. The earthquake determination unit 26 determines whether or not the vibration is an earthquake based on the determination result of the total change variation determination unit 25 regarding the presence or absence of variation. This allows the system to determine whether the detected vibration is an earthquake or noise based on the variation in the total change in velocity over a predetermined period, thereby detecting vibrations with a nearly constant force applied as noise without misidentifying them as earthquakes. As a result, it is possible to accurately determine whether the detected vibration is from an earthquake or noise.

[0059] [Other embodiments] Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications are possible without departing from the spirit of the invention.

[0060] (A) In the above embodiments, examples of the present invention were described using the seismic sensor 10 and the earthquake determination method. However, the present invention is not limited thereto. For example, the present invention may be implemented as an earthquake determination program that causes a computer to execute the earthquake determination method using the seismic sensor described above.

[0061] This earthquake detection program is stored in the memory (storage unit) of the seismic sensor. The CPU reads the earthquake detection program stored in memory and has the hardware execute each step. More specifically, the same effect as described above can be obtained by having the CPU read the earthquake detection program and execute the steps described above. Furthermore, the present invention may be implemented as a recording medium that stores an earthquake judgment program for a seismic sensor.

[0062] (B) In the above embodiment, an example was given in which the acceleration waveform generation unit 22 generates the acceleration waveform shown in Figure 3(a) from the detected vibration acceleration. However, the present invention is not limited thereto. For example, if the total change in velocity is calculated directly by integrating the absolute value of acceleration without generating an acceleration waveform, then an earthquake sensor without an acceleration waveform generation unit may be used.

[0063] (C) In the above embodiment, an example was given in which the earthquake determination unit 26 uses the coefficient of variation as an index indicating the variation in the total change in speed over a certain period when determining whether an earthquake or noise has occurred. However, the present invention is not limited thereto. For example, instead of the coefficient of variation, the earthquake detection unit may use other numerical values ​​such as variance or standard deviation as indicators showing the variability of the total change in speed over a certain period to determine whether it is an earthquake or noise.

[0064] (D) In the above embodiment, an example was given in which the total change in speed is calculated by taking the sum of three cumulative values ​​as the total change in speed. However, the present invention is not limited to this. For example, the number of cumulative values ​​to be summed is not limited to three; it can be any number. Alternatively, instead of taking the sum, the average value can be used as the total change in speed.

[0065] (E) In the above embodiment, an example was described in which a memory unit 30 for storing earthquake judgment results, etc., is provided inside the seismic sensor 10. However, the present invention is not limited to this. For example, the memory unit that stores the results of earthquake assessments, etc., may be located on an external server such as a cloud server.

[0066] <Note> The earthquake sensor according to the first invention is An acceleration acquisition unit that acquires the acceleration of vibrations, A total speed change calculation unit calculates the total speed change over a predetermined fixed section based on the acceleration acquired by the acceleration acquisition unit, A total change variation determination unit that determines whether or not there is variation in the total change in speed calculated by the total change in speed calculation unit in each of the multiple predetermined fixed intervals, An earthquake determination unit determines whether the vibration is an earthquake or not, according to the determination result of the presence or absence of the variation in the total change variation determination unit, It is equipped with.

[0067] The seismic sensor according to the second invention is the seismic sensor according to the first invention, The unit that calculates the total change in speed calculates the total change in speed by integrating the absolute value of the acceleration over the given interval. The seismic sensor according to the third invention is a seismic sensor according to the first or second invention, The earthquake determination unit determines that the vibration is noise when the total change variation determination unit determines that the variation is smaller than a predetermined threshold.

[0068] The seismic sensor according to the fourth invention is a seismic sensor according to any one of the first to third inventions, The earthquake determination unit determines that the vibration is an earthquake when the total change variation determination unit determines that the variation is greater than or equal to a predetermined threshold. The seismic sensor according to the fifth invention is a seismic sensor according to any one of the first to fourth inventions, The acceleration waveform generation unit further comprises an acceleration waveform generation unit that generates an acceleration waveform showing the relationship between the acceleration measured in the acceleration acquisition unit and the elapsed time, The total speed change calculation unit calculates the total speed change from the acceleration waveform generated by the acceleration waveform generation unit.

[0069] The earthquake sensor according to the sixth invention is an earthquake sensor according to any one of the first to fifth inventions, The system further includes an earthquake magnitude calculation unit that determines whether an earthquake is of a predetermined seismic intensity or higher when the earthquake determination unit determines that an earthquake has occurred. The seismic sensor according to the seventh invention is a seismic sensor according to any one of the first to sixth inventions, The system further includes a startup determination unit that calculates the intensity of the vibration from the measurement results in the acceleration acquisition unit, and switches from the power-saving mode to a measurement mode that consumes more power than the power-saving mode if the intensity of the vibration is greater than or equal to a predetermined magnitude.

[0070] The seismic sensor according to the eighth invention is a seismic sensor according to any one of the first to seventh inventions, The earthquake determination unit further includes an output control unit that outputs a predetermined signal when it is determined that an earthquake has occurred. The seismic sensor according to the ninth invention is a seismic sensor according to any one of the first to eighth inventions, The system further includes a storage unit for storing the determination results from the total change variation determination unit and the earthquake determination unit. [Industrial applicability]

[0071] The seismic sensor of the present invention has the effect of being able to accurately determine whether the detected vibration is an earthquake or noise, and therefore can be widely applied to sensors that detect various types of vibrations. [Explanation of Symbols]

[0072] 10. Earthquake Sensor 11. Accelerometer 12 controllers 13 memory 14 Output section 21 Acceleration acquisition section 22 Acceleration waveform generator 23 Vibration intensity classification / startup determination section 24. Total Speed ​​Change Calculation Unit 25 Total change variation determination unit 26 Earthquake Determination Department 27 Earthquake scale calculation department 28 Output control unit 30 Storage section

Claims

1. An acceleration acquisition unit that acquires the acceleration of vibrations, A total speed change calculation unit calculates the total speed change over a predetermined fixed section based on the acceleration acquired by the acceleration acquisition unit, A total change variation determination unit that determines whether or not there is variation in the total change in speed calculated by the total change in speed calculation unit in each of the multiple predetermined fixed intervals, An earthquake determination unit determines whether the vibration is an earthquake or not, according to the determination result of the presence or absence of the variation in the total change variation determination unit, An earthquake sensor equipped with this feature.

2. The unit that calculates the total change in speed calculates the total change in speed by integrating the absolute value of the acceleration over the given interval. The seismic sensor according to claim 1.

3. The earthquake determination unit determines that the total variation determination unit determines that the variation is smaller than a predetermined threshold, and then determines that the vibration is noise. The seismic sensor according to claim 1 or 2.

4. The earthquake determination unit determines that the vibration is an earthquake when the total variation variation determination unit determines that the variation is greater than or equal to a predetermined threshold. The seismic sensor according to claim 1 or 2.

5. The acceleration waveform generation unit further comprises an acceleration waveform generation unit that generates an acceleration waveform showing the relationship between the acceleration measured in the acceleration acquisition unit and the elapsed time, The total speed change calculation unit calculates the total speed change from the acceleration waveform generated in the acceleration waveform generation unit. The seismic sensor according to claim 1 or 2.

6. The system further includes an earthquake magnitude calculation unit that determines whether an earthquake is of a predetermined seismic intensity or higher when the earthquake determination unit determines that an earthquake has occurred. The seismic sensor according to claim 1 or 2.

7. The system further includes a startup determination unit that calculates the vibration intensity from the measurement results of the acceleration acquisition unit, and, if the vibration intensity is greater than or equal to a predetermined magnitude, switches from the power-saving mode to a measurement mode that consumes more power than the power-saving mode. The seismic sensor according to claim 1 or 2.

8. The earthquake determination unit further includes an output control unit that outputs a predetermined signal when it is determined that an earthquake has occurred. The seismic sensor according to claim 1 or 2.

9. The system further includes a storage unit for storing the determination results from the total change variation determination unit and the earthquake determination unit. The seismic sensor according to claim 1 or 2.

10. Obtain the acceleration of the vibration, From the acceleration obtained from the start to the end of the vibration, the total change in velocity over a certain period is calculated. Determine whether there is any variation in the calculated total change in speed. Depending on the result of determining whether or not there is variation, it is determined whether or not the vibration is an earthquake. Earthquake determination method.

11. Obtain the acceleration of the vibration, From the acceleration obtained from the start to the end of the vibration, the total change in velocity over a certain period is calculated. Determine whether there is any variation in the calculated total change in speed. Depending on the result of determining whether or not there is variation, it is determined whether or not the vibration is an earthquake. An earthquake prediction program that uses a computer to execute earthquake prediction methods.

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