JP7223482B2 - Abnormal Natural Phenomenon Detection System and Abnormal Natural Phenomenon Detection Method - Google Patents

Description

The present invention is a technology for detecting natural phenomena that lead to disasters such as debris flows and avalanches (hereinafter referred to as "abnormal natural phenomena"). It relates to a system for detecting phenomena and a method using the same.

It is said that two-thirds of Japan's land is mountainous, so many people live on land with slopes behind them, and roads and railroads almost always pass along the sides of slopes. be. Abnormal natural phenomena such as debris flows, avalanches, slope failures, and landslides occurring on mountainsides and slopes have often caused extensive damage to houses and roads.

Of these, debris flows are known to move at speeds of 20-40 km/h, while surface avalanches move at speeds of 100-200 km/h. It can be said.

In addition, once a debris flow or avalanche occurs, it may occur intermittently thereafter, which is an abnormal natural phenomenon that requires attention to secondary disasters. In the past, an avalanche occurred on an arterial road in the Kyrgyz Republic, and there were also accidents in which those involved in the restoration work were damaged by subsequent avalanches.

In order to avoid such disasters caused by debris flows and avalanches, to reduce the damage, and to avoid secondary disasters, it is extremely important to detect the occurrence of debris flows and avalanches as early as possible and accurately. is important. Various techniques for detecting debris flows and avalanches have been proposed so far, and efforts have been made to actually detect them using these techniques.

For example, vibration sensors and wire sensors are used to detect the occurrence of debris flows. The detection method using a vibration sensor detects the movement of a debris flow with a vibration sensor. Prediction technology is required, and since it cannot be installed after an occurrence, it cannot be adopted for the purpose of avoiding secondary disasters. On the other hand, the detection method using a wire sensor detects the occurrence of a debris flow when the wire is cut. Prediction technology is required, and it cannot be used for the purpose of avoiding secondary disasters. Moreover, the detection method using these vibration detection type sensors and wire sensors cannot be used continuously once a debris flow occurs.

Therefore, Japanese Patent Laid-Open No. 2002-200001 proposes a debris flow detection technique that enables continuous detection without re-installing a sensor or the like after the occurrence of the debris flow.

Japanese Patent Application Laid-Open No. 2004-205433

The technology disclosed in Patent Document 1 detects the occurrence of a debris flow by measuring the deflection of a sensor rod suspended like a pendulum. can. However, in the case of experiencing a large-scale debris flow or a rapidly moving debris flow, the device of Patent Document 1 may be destroyed, in which case a new device must be installed. In addition, the device of Patent Document 1 must be installed in a place where a debris flow is expected to occur, and considering that it cannot be installed after the debris flow occurs, it cannot be adopted for the purpose of avoiding secondary disasters. .

The object of the present invention is to solve the conventional problem, that is, to avoid a secondary disaster without installing a sensor or the like in a place where a debris flow is expected to occur. It is to provide a phenomenon detection system and a detection method using the system.

In the present invention, a directional microphone is installed at a downstream position away from a place where an abnormal natural phenomenon such as a debris flow or an avalanche is predicted to occur (hereinafter referred to as "predicted occurrence place"), and this directional microphone It focuses on detecting the occurrence of abnormal natural phenomena by using the acquired acoustic vibration pattern and the noise acquired by the omnidirectional microphone installed around the directional microphone. It is an invention made based on an idea that did not exist.

The abnormal natural phenomenon detection system of the present invention is a system for detecting abnormal natural phenomena, and comprises abnormal pattern storage means, main recording means, secondary recording means, noise processing means, estimation means, and warning information output means. be. Among these, the abnormal pattern storage means is means for storing abnormal acoustic vibration patterns (patterns of acoustic vibrations of abnormal natural phenomena). The main sound recording means is a directional microphone, and the auxiliary sound recording means is an omnidirectional microphone. The noise processing means is means for obtaining a target acoustic vibration pattern by treating the acoustic vibration pattern acquired by the secondary recording means as noise and removing the noise from the acoustic vibration pattern acquired by the main recording means. The estimation means is means for estimating the occurrence of an abnormal natural phenomenon by comparing the target acoustic vibration pattern obtained by the noise processing means with the abnormal acoustic vibration pattern stored in the abnormal pattern storage means. The warning information output means is means for issuing an alarm when the estimation means estimates the occurrence of an abnormal natural phenomenon. In addition, the main recording means is installed facing the predicted occurrence point so as to acquire the acoustic vibration in the direction of the predicted occurrence point (the point where the abnormal natural phenomenon is predicted to occur), and the secondary recording means is installed in the main recording means. It is installed around the installation position of the main sound recording means so as to acquire the acoustic vibration around the position.

The abnormal natural phenomenon detection system of the present invention can also distinguish between a debris flow and an avalanche and issue an alarm. In this case, the abnormal pattern storage means stores the "abnormal acoustic vibration pattern when a debris flow occurs" and the "abnormal acoustic vibration pattern when an avalanche occurs", and the estimating means discriminates between a debris flow and an avalanche to detect abnormal natural conditions. Presume the occurrence of the phenomenon.

The abnormal natural phenomenon detection system of the present invention can also detect the occurrence of an abnormal natural phenomenon by comparing the magnitude of amplitude in the target acoustic vibration pattern with the magnitude of amplitude in the abnormal acoustic vibration pattern.

The abnormal natural phenomenon detection system of the present invention can also detect the occurrence of an abnormal natural phenomenon by comparing the frequency of the target acoustic vibration pattern with the frequency of the abnormal acoustic vibration pattern.

The abnormal natural phenomenon detection system of the present invention can also detect the occurrence of an abnormal natural phenomenon by comparing the target acoustic vibration pattern with the premonitory acoustic vibration pattern. In this case, the abnormal pattern storage means stores a "precursor acoustic vibration pattern" which is a pattern of acoustic vibrations before the debris flow occurs.

The abnormal natural phenomenon detection method of the present invention is a method for detecting an abnormal natural phenomenon, and is a method comprising a main recording means installation step, a sub recording means installation step, a noise processing step, an estimation step, and an alarm step. Among these steps, in the main sound recording means installation step, the main sound recording means is installed facing the predicted generation location so as to acquire the acoustic vibration in the direction of the predicted generation location. In the sub-recording means installation step, the sub-recording means is installed around the installation position of the main recording means so as to acquire acoustic vibrations around the installation position of the main recording means. In the noise processing step, the acoustic vibration pattern acquired by the secondary recording means is treated as noise, and the noise is removed from the acoustic vibration pattern acquired by the main recording means to obtain a target acoustic vibration pattern. In the estimation step, the occurrence of an abnormal natural phenomenon is estimated by comparing the target acoustic vibration pattern obtained in the noise processing step with the abnormal acoustic vibration pattern. Then, in the alarm process, an alarm is issued when occurrence of an abnormal natural phenomenon is estimated in the estimation process.

The abnormal natural phenomenon detection system and the abnormal natural phenomenon detection method of the present invention have the following effects.
(1) It is a non-contact system and can be used repeatedly even after a debris flow or avalanche occurs.
(2) It does not require large-scale equipment and is highly portable, so it has a high degree of freedom in terms of installation location and can be quickly installed and operated even in the event of a disaster. As a result, it can be suitably employed also for the purpose of avoiding secondary disasters.
(3) It can be used even in situations where visibility is poor, such as at night or in thick fog.
(4) If a commercially available portable terminal (smartphone, etc.) is used as a secondary recording means, it will be easier to develop and update software used for noise processing means (noise processing process) and estimation means (estimation process). By incorporating learning, it is possible to further improve the system for detecting abnormal natural phenomena.
(5) By using a commercially available portable terminal (smartphone, etc.) as a means of communication, various warnings can be issued through the network.

1 is a block diagram showing the main configuration of an abnormal natural phenomenon detection system of the present invention; FIG. FIG. 4 is a model diagram schematically showing the arrangement relationship between the main recording means and the sub-recording means; The flowchart which shows the flow of the main processes of the abnormal natural phenomenon detection system of this invention. FIG. 4 is a model diagram showing abnormal pattern storage means for storing various abnormal acoustic vibration patterns and portent acoustic vibration patterns; The flowchart which shows the main process of the abnormal natural phenomenon detection method of this invention.

An example of an embodiment of an abnormal natural phenomenon detection system and an abnormal natural phenomenon detection method of the present invention will be described with reference to the drawings.

First, an outline of the present invention will be described. The present invention detects an abnormal natural phenomenon based on the "acoustic vibration pattern" acquired by the "main recording means" installed toward the "predicted occurrence location", and the "secondary recording means" installed around the main recording means. One feature is that the "acoustic vibration pattern" acquired by the "recording means" is processed as noise. The main recording means acquires not only the acoustic vibration at the intended occurrence predicted location but also the acoustic vibration around the installation. Therefore, we decided to use the sub-recording means that mainly acquires the acoustic vibration around the main recording means. That is, the acoustic vibration pattern acquired by the secondary recording means is removed as noise from the acoustic vibration pattern acquired by the main recording means, and the target acoustic vibration pattern obtained as a result (hereinafter referred to as the "target acoustic vibration pattern") Based on this, abnormal natural phenomena are detected. Therefore, it is preferable that the main recording means is a directional microphone, and the sub-recording means is an omnidirectional microphone. Here, the “predicted location” is the location where an abnormal natural phenomenon (natural phenomenon leading to disasters such as debris flow and avalanche) is predicted to occur, and the “acoustic vibration pattern” is the location within a predetermined period of time. It is the time variation of the acoustic vibration acquired in

When the target acoustic vibration pattern is obtained, it is compared with the "abnormal acoustic vibration pattern", and when it is determined that the target acoustic vibration pattern and the abnormal acoustic vibration pattern match or approximate each other, the occurrence of an abnormal natural phenomenon is estimated. The "abnormal acoustic vibration pattern" is an acoustic vibration pattern obtained when an abnormal natural phenomenon actually occurs, and is prepared in advance.

Hereinafter, the abnormal natural phenomenon detection system and the abnormal natural phenomenon detection method of the present invention will be described in detail. The abnormal natural phenomenon detection method of the present invention is a method of detecting an abnormal natural phenomenon using the abnormal natural phenomenon detection system of the present invention. The abnormal natural phenomenon detection method of the invention will be described.

2. Abnormal Natural Phenomenon Detection System FIG. 1 is a block diagram showing the main configuration of an abnormal natural phenomenon detection system 100 of the present invention. As shown in this figure, the abnormal natural phenomenon detection system 100 of the present invention includes main recording means 101, sub-recording means 102, noise processing means 103, estimation means 104, abnormal pattern storage means 105, and warning information output means 106. Configured.

Of the means that make up the abnormal natural phenomenon detection system 100, the noise processing means 103, the estimation means 104, and the warning information output means 106 can be manufactured as dedicated ones, or a general-purpose computer device can be used. can also This computer device can be configured by a personal computer (PC), a tablet PC such as an iPad (registered trademark), a mobile terminal including a smart phone, a PDA (Personal Data Assistance), or the like. A computer device includes a processor such as a CPU, memory such as a ROM and a RAM, and may further include input means such as a mouse and a keyboard, and a display.

The abnormal pattern storage means 105 can be constructed, for example, in a database server, and can be connected (image data communication) with the noise processing means 103 via a local network (LAN: Local Area Network), or via the Internet (that is, wireless communication). It can also be a cloud server that saves in. In addition, the abnormal natural phenomenon detection system 100 includes a "main acoustic vibration storage means" that stores the acoustic vibrations acquired by the main recording means 101, and a "secondary acoustic vibration storage means" that stores the acoustic vibrations acquired by the secondary recording means 102. ” can also be included. The primary acoustic vibration storage means, the secondary acoustic vibration storage means, and the abnormal pattern storage means 105 can be built in separate database servers, or can be built in the same database server.

As described above, the main recording means 101 acquires the acoustic vibration at the predicted generation location, and is therefore installed facing the predicted generation location as shown in FIG. Also, the main recording means 101 preferably uses a microphone having directivity such as an acoustic location, which is a parabolic sound collector or an acoustic rangefinder, so as to obtain acoustic vibrations in the predicted direction of occurrence as much as possible.

On the other hand, the secondary sound recording means 102 acquires acoustic vibrations around the installation location of the main sound recording means 101, and is therefore installed (arranged) around the main sound recording means 101 as shown in FIG. In addition, the secondary recording means 102 should preferably use an omnidirectional microphone, such as the recording function of a smartphone, so as to acquire sound vibrations around the main recording means 101 as thoroughly as possible.

FIG. 3 is a flow diagram showing the main processing flow of the abnormal natural phenomenon detection system 100 of the present invention. The columns show the output information resulting from the processing. The main processing flow of the abnormal natural phenomenon detection system 100 will be described below with reference to this figure.

When the main recording means 101 and the sub-recording means 102 are installed in the arrangement shown in FIG. Acoustic vibration (hereinafter referred to as "secondary acoustic vibration") is acquired by the recording means 102 (Step 102). When the main sound vibration is continuously acquired by the main sound recording means 101, a sound vibration pattern composed of the main sound vibration (hereinafter referred to as "main sound vibration pattern") is generated. continuously acquires secondary acoustic vibrations, it generates an acoustic vibration pattern (hereinafter referred to as "secondary acoustic vibration pattern") composed of the secondary acoustic vibrations. These primary acoustic vibration pattern and secondary acoustic vibration pattern may be generated periodically (for example, every predetermined period constituting the acoustic vibration pattern) or continuously (for example, every second or every minute). good too. When it is generated periodically at short intervals, or when it is generated continuously, the primary acoustic vibration pattern and the secondary acoustic vibration pattern are generated while partially overlapping the primary acoustic vibration and the secondary acoustic vibration. . The generation of the primary acoustic vibration pattern and the secondary acoustic vibration pattern can be performed using the computer 107 shown in FIG.

When the primary acoustic vibration pattern and the secondary acoustic vibration pattern are generated, the secondary acoustic vibration pattern is treated as noise, and the noise (that is, the secondary acoustic vibration pattern) is removed from the primary acoustic vibration pattern (Step 103). Specifically, noise included in the waveform of the main acoustic vibration pattern is removed, such as by subtracting the waveform of the secondary acoustic vibration pattern from the waveform of the main acoustic vibration pattern. Then, the target acoustic vibration pattern is obtained by removing the noise from the main acoustic vibration pattern.

When the target acoustic vibration pattern is obtained, the abnormal acoustic vibration pattern stored in the abnormal pattern storage means 105 is read out (Step 104). The abnormal pattern storage means 105 preferably stores abnormal acoustic vibration patterns related to various abnormal natural phenomena, such as abnormal acoustic vibration patterns when a debris flow occurs and abnormal acoustic vibration patterns when an avalanche occurs. Furthermore, in addition to the abnormal acoustic vibration pattern after the actual occurrence of the abnormal natural phenomenon, the acoustic vibration pattern as a so-called premonitory phenomenon before the abnormal natural phenomenon occurs (hereinafter referred to as "precursor acoustic vibration pattern") is stored. can also As will be described later, the abnormal pattern storage means 105 stores various abnormal acoustic vibration patterns, so that the type of abnormal natural phenomenon (debris flow, avalanche, etc.) can be estimated. By memorizing patterns, it is possible to quickly (or in advance) detect the occurrence of an abnormal natural phenomenon.

When the abnormal acoustic vibration pattern is read out, occurrence of an abnormal natural phenomenon is estimated by comparing the target acoustic vibration pattern with the abnormal acoustic vibration pattern (Step 105). Specifically, when it is determined that the target acoustic vibration pattern and the abnormal acoustic vibration pattern match or are similar, the occurrence of an abnormal natural phenomenon is estimated, and the target acoustic vibration pattern and the abnormal acoustic vibration pattern are different. If it is determined that there is no abnormal natural phenomenon, it is presumed that there will be no occurrence of the abnormal natural phenomenon. For this approximation determination, various conventionally used techniques including the method of least squares can be used.

Objective Judgment (matching or approximation judgment) between the acoustic vibration pattern and the abnormal acoustic vibration pattern can be made by focusing on the entire waveform, or by focusing on the magnitude and frequency of the amplitude in the acoustic vibration pattern. can also For example, the magnitude of the amplitude in the target acoustic vibration pattern and the magnitude of the amplitude in the abnormal acoustic vibration pattern are compared, and if the magnitudes of the amplitudes approximate (or match) for a certain period of time, the target acoustic vibration pattern and the abnormal acoustic Judge that the vibration patterns are approximate (or match). Alternatively, the frequency of the target acoustic vibration pattern and the frequency of the abnormal acoustic vibration pattern are compared, and if the frequencies approximate (or match) for a certain period of time, the target acoustic vibration pattern and the abnormal acoustic vibration pattern are approximate (or match). ).

Further, when the abnormal pattern storage means 105 stores abnormal acoustic vibration patterns related to various abnormal natural phenomena, it is preferable to read each abnormal acoustic vibration pattern and estimate the occurrence of the abnormal natural phenomenon together with the type thereof. . For example, in a case where an abnormal sound vibration pattern of a debris flow and an abnormal sound vibration pattern of an avalanche are stored in the abnormal pattern storage means 105, the abnormal sound vibration pattern of the debris flow and the abnormal sound vibration pattern of the avalanche are read out, respectively, and the target sound vibration pattern is read out. If the abnormal sound vibration pattern of the debris flow is similar (or matches), the occurrence of the debris flow is estimated, and if the target sound vibration pattern and the abnormal sound vibration pattern of the avalanche are similar (or match), the occurrence of the avalanche is estimated. is.

Furthermore, when the abnormal pattern storage means 105 stores the precursory acoustic vibration pattern, it is preferable to read out the precursory acoustic vibration pattern and then estimate (predict) the occurrence of the abnormal natural phenomenon. For example, in a case where a debris flow precursor acoustic vibration pattern and an avalanche precursor acoustic vibration pattern are stored in the abnormal pattern storage means 105, the debris flow precursor acoustic vibration pattern and the avalanche precursor acoustic vibration pattern are read out, respectively, and the target acoustic vibration pattern is read out. If the sound and vibration patterns that are precursors to the debris flow are similar (or match), the occurrence of a debris flow is estimated (predicted). It estimates (predicts).

When the occurrence of an abnormal natural phenomenon is estimated, the warning information output means 106 instructs output means such as a display, a printer, and an audio output device to output "warning information" (Step 106). At this time, it is also possible to output the "warning information" to one voice output device or the like, or as shown in FIG. information can also be output.

2. Abnormal Natural Phenomenon Detection Method Next, the abnormal natural phenomenon detection method of the present invention will be described with reference to the drawings. It should be noted that the abnormal natural phenomenon detection method of the present invention is a method of detecting an abnormal natural phenomenon using the abnormal natural phenomenon detection system 100 described above, and therefore overlaps with the content described in the abnormal natural phenomenon detection system 100. Explanation is avoided, and only contents specific to the abnormal natural phenomenon detection method of the present invention will be explained. That is, the contents not described here are the same as those described in "1. Abnormal Natural Phenomenon Detection System".

FIG. 5 is a flowchart showing the main steps of the abnormal natural phenomenon detection method of the present invention. As shown in this figure, first, the main recording means 101 and the sub-recording means 102 are installed (Step 201, Step 202). As described above, the main recording means 101 is installed facing the expected occurrence location, while the sub recording means 102 is installed (arranged) around the main recording means 101 .

When the main sound recording means 101 and the secondary sound recording means 102 are installed, the main sound vibration pattern is generated based on the main sound vibration acquired by the main sound recording means 101 (Step 203), and based on the secondary sound vibration acquired by the secondary sound recording means 102. A secondary acoustic vibration pattern is generated (Step 204), and a target acoustic vibration pattern is generated by removing the secondary acoustic vibration pattern, which is noise, from the main acoustic vibration pattern (Step 205).

When the target acoustic vibration pattern is obtained, the abnormal acoustic vibration pattern is read from the abnormal pattern storage means 105, and this abnormal acoustic vibration pattern is compared with the target acoustic vibration pattern (Step 206). As a result, when it is determined that the target acoustic vibration pattern and the abnormal acoustic vibration pattern approximate (or match), the occurrence of an abnormal natural phenomenon is estimated (Yes in Step 206), and the target acoustic vibration pattern and the abnormal acoustic vibration pattern are estimated to occur. When it is determined that the patterns are different (No in Step 207), the main recording means 101 continuously acquires the primary acoustic vibration, and the secondary recording means 102 acquires the secondary acoustic vibration. Then, when the occurrence of an abnormal natural phenomenon is estimated, for example, "warning information" is output simultaneously to a plurality of terminal devices 108 (Step 208).

The abnormal natural phenomenon detection system and abnormal natural phenomenon detection method of the present invention can be used not only for debris flows and avalanches, but also for surface collapses and landslides on natural slopes, and when aiming to avoid secondary disasters. It can be used particularly effectively. Considering that in the event of a disaster, early evacuation can be urged and as a result the safety of many people can be ensured, it can be said that this invention can be expected not only to be used industrially but also to make a great contribution to society.

100 Abnormal Natural Phenomenon Detection System 101 Main Recording Means (of Abnormal Natural Phenomenon Detection System) 102 Secondary Recording Means (of Abnormal Natural Phenomenon Detection System) 103 Noise Processing Means (of Abnormal Natural Phenomenon Detection System) 104 (Abnormal Natural Phenomenon Detection System) ) Estimation means 105 Abnormal pattern storage means (of abnormal natural phenomenon detection system) 106 Warning information output means (of abnormal natural phenomenon detection system) 107 Computer (of abnormal natural phenomenon detection system) 108 Terminal device (of abnormal natural phenomenon detection system)

Claims (6)

In systems that detect abnormal natural phenomena, including debris flows and avalanches,
abnormal pattern storage means for storing an abnormal acoustic vibration pattern, which is a pattern of acoustic vibration of the abnormal natural phenomenon;
a main recording means that is a directional microphone;
a secondary recording means that is an omnidirectional microphone;
noise processing means for obtaining a target acoustic vibration pattern by treating the acoustic vibration pattern acquired by the secondary recording means as noise and removing the noise from the acoustic vibration pattern acquired by the main recording means;
estimating means for estimating occurrence of the abnormal natural phenomenon by comparing the target acoustic vibration pattern obtained by the noise processing means with the abnormal acoustic vibration pattern stored in the abnormal pattern storage means;
warning information output means for issuing an alarm when the occurrence of the abnormal natural phenomenon is estimated by the estimation means;
The main sound recording means is installed at a downstream position away from the predicted location where the abnormal natural phenomenon is predicted to occur, and is installed facing the predicted occurrence location so as to acquire acoustic vibration in the direction of the predicted occurrence location. is,
The secondary recording means is installed around the installation position of the main recording means so as to acquire acoustic vibrations around the installation position of the main recording means,
An abnormal natural phenomenon detection system characterized by: The abnormal pattern storage means stores the abnormal acoustic vibration pattern when a debris flow occurs and the abnormal acoustic vibration pattern when an avalanche occurs,
The estimation means estimates the occurrence of the abnormal natural phenomenon by distinguishing between a debris flow and an avalanche;
The warning information output means distinguishes between a debris flow and an avalanche and issues an alarm.
The abnormal natural phenomenon detection system according to claim 1, characterized in that: The estimating means estimates the occurrence of the abnormal natural phenomenon by comparing the magnitude of amplitude in the target acoustic vibration pattern with the magnitude of amplitude in the abnormal acoustic vibration pattern.
3. The abnormal natural phenomenon detection system according to claim 1 or 2, characterized in that: The estimation means estimates the occurrence of the abnormal natural phenomenon by comparing the frequency of the target acoustic vibration pattern with the frequency of the abnormal acoustic vibration pattern.
3. The abnormal natural phenomenon detection system according to claim 1 or 2, characterized in that: The abnormal pattern storage means stores a premonitory acoustic vibration pattern, which is a pattern of acoustic vibrations before a debris flow occurs,
The estimating means estimates the occurrence of the abnormal natural phenomenon by comparing the target acoustic vibration pattern with the abnormal acoustic vibration pattern or the precursory acoustic vibration pattern.
The abnormal natural phenomenon detection system according to any one of claims 1 to 4, characterized in that: In a method for detecting abnormal natural phenomena including debris flows and avalanches,
The main sound recording means, which is a microphone having directivity , is positioned downstream from the predicted location where the abnormal natural phenomenon is predicted to occur and acquires acoustic vibration in the direction of the predicted location. A main recording means installation step installed toward the predicted occurrence location;
A secondary sound recording means installation step of installing a secondary sound recording means, which is an omnidirectional microphone, in the vicinity of the installation position of the main sound recording means so as to acquire acoustic vibrations around the installation position of the main sound recording means;
a noise processing step of obtaining a target acoustic vibration pattern by treating the acoustic vibration pattern acquired by the secondary recording means as noise and removing the noise from the acoustic vibration pattern acquired by the main recording means;
an estimation step of estimating the occurrence of the abnormal natural phenomenon by comparing the target acoustic vibration pattern obtained in the noise processing step with an abnormal acoustic vibration pattern that is a pattern of acoustic vibration of the abnormal natural phenomenon;
an alarm step of issuing an alarm when the occurrence of the abnormal natural phenomenon is estimated in the estimation step;
A method for detecting an abnormal natural phenomenon, comprising:

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