Optical communication underground facility location comparison system, optical communication underground facility location comparison method, and optical communication underground facility location comparison device

Abstract

The present disclosure is an underground equipment location reference system S characterized by comprising: a scattered light intensity distribution measurement device 1 that, when seismic vibration is applied to an optical fiber F laid underground, measures the change over time in the scattered light intensity distribution in the longitudinal direction of the optical fiber F; and an underground equipment location reference device 2 that, on the basis of the change over time in the scattered light intensity distribution in the longitudinal direction of the optical fiber F, measures the change over time in the strain response distribution in the longitudinal direction of the optical fiber F, and that, on the basis of the change over time in the strain response distribution in the longitudinal direction of the optical fiber F, associates the underground equipment location of the optical fiber F with the distance in the longitudinal direction of the optical fiber F.

Description

[Technical field]

[0001] The present disclosure relates to a technique for associating the location of an underground optical fiber facility with the longitudinal distance of the optical fiber, based on a time change in the scattered light intensity distribution in the longitudinal direction of the optical fiber. [Background technology]

[0002] When laying optical fibers underground, manholes are placed underground and the optical fibers are cable-connected inside the manholes. When an abnormality occurs in the optical fiber at a certain position, the position of the manhole must be associated with the longitudinal distance of the optical fiber in order to identify the position of the manhole where work should be performed (see, for example, Non-Patent Document 1).

[0003] A specific example of a conventional optical communication underground facility location comparison process is shown in Fig. 1. When an optical fiber F is laid under the ground G, it is laid in a pipe T and connected by a closure C under a manhole M. An optical communication central building B is equipped with an underground facility location comparison system S.

[0004] The underground facility location comparison system S measures the time change in the scattered light intensity distribution in the longitudinal direction of the optical fiber F when an intentional strike is applied to the cover of the manhole M. Then, using an optical time domain backscattering measurement method or the like, it measures the time change in the strain response distribution in the longitudinal direction of the optical fiber F based on the time change in the scattered light intensity distribution in the longitudinal direction of the optical fiber F. Furthermore, based on the time change in the strain response distribution in the longitudinal direction of the optical fiber F, it estimates the presence or absence of a manhole M and associates the position of the manhole M with the longitudinal distance of the optical fiber F.

[0005] Here, in the vicinity of a longitudinal distance of 1340 m of optical fiber F, the time change in the strain response of optical fiber F indicates the presence of an intentional strike with a period of 1 s. On the other hand, in the vicinity of a longitudinal distance of 1360 m of optical fiber F, the time change in the strain response of optical fiber F does not indicate the presence of an intentional strike with a period of 1 s. Therefore, the underground facility position comparison system S can associate the position of manhole M with the vicinity of a longitudinal distance of 1340 m of optical fiber F. [Prior art documents] [Non-patent literature]

[0006] [Non-Patent Document 1] D. Iida, N. Honda, and H. Oshida, “Advances in distributed vibration sensing for optical communication fiber state visualization,” Optical Fiber Technol.,57,102263,2020. Summary of the Invention [Problem to be solved by the invention]

[0007] However, the underground facility location comparison system S requires dispatching personnel to the site to intentionally strike the cover of the manhole M, and therefore cannot reduce the human operating rate.

[0008] Therefore, in order to solve the above problem, an object of the present disclosure is to reduce the human operation rate when associating the location of an underground optical fiber facility with the longitudinal distance of the optical fiber. [Means for solving the problem]

[0009] In order to solve the above problem, the inventors decided to measure the change over time in the scattered light intensity distribution in the longitudinal direction of an underground laid optical fiber when earthquake vibrations are applied to the optical fiber.

[0010] Specifically, the present disclosure relates to an optical communication underground facility position comparison system comprising: a scattered light intensity distribution measuring device that measures the time change in the scattered light intensity distribution in the longitudinal direction of an optical fiber when seismic vibrations are applied to the optical fiber laid underground; and an underground facility position comparison device that measures the time change in the longitudinal strain response distribution of the optical fiber based on the time change in the scattered light intensity distribution in the longitudinal direction of the optical fiber, estimates the underground facility state of the optical fiber based on the time change in the longitudinal strain response distribution of the optical fiber, and corresponds the underground facility position of the optical fiber to the longitudinal distance of the optical fiber.

[0011] The present disclosure also relates to an optical communication underground facility location comparison method, comprising, in order, a scattered light intensity distribution acquisition step of acquiring information on a time change in the scattered light intensity distribution in the longitudinal direction of the optical fiber when seismic vibrations are applied to the optical fiber laid underground; a strain response distribution measurement step of measuring a time change in a strain response distribution in the longitudinal direction of the optical fiber based on the time change in the scattered light intensity distribution in the longitudinal direction of the optical fiber; and an underground facility location comparison step of estimating an underground facility state of the optical fiber based on the time change in the strain response distribution in the longitudinal direction of the optical fiber and correlating the underground facility location of the optical fiber with the longitudinal distance of the optical fiber.

[0012] The present disclosure also relates to an optical communication underground facility position comparison device, comprising: a scattered light intensity distribution acquisition unit that acquires information on the time change in scattered light intensity distribution in the longitudinal direction of the optical fiber when seismic vibrations are applied to the optical fiber laid underground; a strain response distribution measurement unit that measures the time change in strain response distribution in the longitudinal direction of the optical fiber based on the time change in scattered light intensity distribution in the longitudinal direction of the optical fiber; and an underground facility position comparison unit that estimates the underground facility state of the optical fiber based on the time change in strain response distribution in the longitudinal direction of the optical fiber and corresponds the underground facility position of the optical fiber to the longitudinal distance of the optical fiber.

[0013] These configurations utilize earthquake vibrations applied to the optical fiber rather than intentionally applying a strike to the manhole cover, thereby reducing the human operating rate when matching the location of the underground optical fiber facility to the longitudinal distance of the optical fiber.

[0014] The present disclosure also relates to an optical communication underground facility location comparison system, characterized in that the underground facility location comparison device measures a time change in a vibration frequency distribution in the longitudinal direction of the optical fiber based on a time change in a scattered light intensity distribution in the longitudinal direction of the optical fiber, estimates an underground facility state of the optical fiber based on whether the time change in the vibration frequency distribution in the longitudinal direction of the optical fiber is continuous or discontinuous over the longitudinal distance of the optical fiber, and corresponds the underground facility position of the optical fiber to the longitudinal distance of the optical fiber.

[0015] According to this configuration, the positions of manhole sections, pipeline sections, etc. can be associated with the longitudinal distance of the optical fiber based on whether the change over time in the longitudinal vibration frequency distribution of the optical fiber is continuous or discontinuous over the longitudinal distance of the optical fiber.

[0016] The present disclosure also relates to an optical communication underground facility location comparison system, characterized in that the underground facility location comparison device measures a time change in a vibration frequency distribution in the longitudinal direction of the optical fiber based on a time change in a scattered light intensity distribution in the longitudinal direction of the optical fiber, estimates an underground facility state of the optical fiber based on whether the time change in the vibration frequency distribution in the longitudinal direction of the optical fiber matches or does not match a time change in the vibration frequency of the earthquake vibration, and corresponds the underground facility location of the optical fiber to the longitudinal distance of the optical fiber.

[0017] According to this configuration, the positions of manhole sections, pipeline sections, etc. can be associated with the longitudinal distance of the optical fiber based on whether the time change in the longitudinal vibration frequency distribution of the optical fiber matches or does not match the time change in the vibration frequency of earthquake vibrations.

[0018] The present disclosure also relates to an optical communication underground facility location comparison system, characterized in that the underground facility location comparison device measures a time change in a longitudinal strain amplitude distribution of the optical fiber based on a time change in a longitudinal scattered light intensity distribution of the optical fiber, estimates an underground facility state of the optical fiber based on whether the time change in the longitudinal strain amplitude distribution of the optical fiber is continuous or discontinuous over the longitudinal distance of the optical fiber, and corresponds the underground facility position of the optical fiber to the longitudinal distance of the optical fiber.

[0019] According to this configuration, the positions of manhole sections, pipeline sections, etc. can be associated with the longitudinal distance of the optical fiber based on whether the change over time in the longitudinal strain amplitude distribution of the optical fiber is continuous or discontinuous over the longitudinal distance of the optical fiber. Effect of the Invention

[0020] In this manner, the present disclosure can reduce the human operating rate when associating the underground facility location of the optical fiber with the longitudinal distance of the optical fiber. [Brief description of the drawings]

[0021] [Figure 1] FIG. 1 is a diagram showing a specific example of a conventional optical communication underground facility location comparison process. [Diagram 2] FIG. 1 is a diagram showing the configuration of an optical communication underground facility location comparison system according to the present disclosure. [Diagram 3] FIG. 4 is a diagram showing a procedure of an underground optical communication facility position comparison process according to the first embodiment. [Figure 4] 4A to 4C are diagrams illustrating a specific example of the optical communication underground facility position comparison process according to the first embodiment. [Diagram 5] FIG. 11 is a diagram showing a procedure of an underground optical communication facility position comparison process according to the second embodiment. [Figure 6] FIG. 11 is a diagram showing a specific example of the optical communication underground facility position comparison process according to the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present disclosure will be described with reference to the accompanying drawings. The embodiments described below are examples of the present disclosure, and the present disclosure is not limited to the following embodiments.

[0023] (Configuration of the optical communication underground facility location comparison system disclosed herein) The configuration of the optical communication underground facility location comparison system disclosed herein is shown in Fig. 2. The underground facility location comparison system S comprises a scattered light intensity distribution measuring device 1 and an underground facility location comparison device 2. The underground facility location comparison device 2 comprises a scattered light intensity distribution acquiring unit 21, a strain response distribution measuring unit 22 and an underground facility location comparison unit 23. The underground facility location comparison device 2 can be realized by installing an underground facility location comparison program shown in Fig. 3 and / or Fig. 5 (which can be recorded on a recording medium or provided over a network) in a computer.

[0024] When earthquake vibrations are applied to an underground laid optical fiber F, the scattered light intensity distribution measuring device 1 measures the time change in the scattered light intensity distribution in the longitudinal direction of the optical fiber F. When earthquake vibrations are applied to the underground laid optical fiber F, the scattered light intensity distribution acquiring unit 21 acquires information on the time change in the scattered light intensity distribution in the longitudinal direction of the optical fiber F.

[0025] The strain response distribution measurement unit 22 uses an optical time domain backscattering measurement method or the like to measure the time change in the strain response distribution in the longitudinal direction of the optical fiber F based on the time change in the scattered light intensity distribution in the longitudinal direction of the optical fiber F. The underground facility position comparison unit 23 estimates the underground facility state of the optical fiber F based on the time change in the strain response distribution in the longitudinal direction of the optical fiber F, associates the underground facility position of the optical fiber F with the longitudinal distance of the optical fiber F, and notifies the optical communications central building B.

[0026] In this way, since the earthquake vibrations applied to the optical fiber F are utilized instead of the intentional impact applied to the cover of the manhole M, the human operating rate can be reduced when matching the underground facility position of the optical fiber F to the longitudinal distance of the optical fiber F.

[0027] (Procedure for processing to compare the location of underground optical communication facilities in the first embodiment) The procedure of the underground optical communication facility position comparison process of the first embodiment is shown in Fig. 3. The scattered light intensity distribution acquisition unit 21 acquires information on the time change in the scattered light intensity distribution in the longitudinal direction of the optical fiber F when earthquake vibration is applied to the optical fiber F laid underground (step S1). The strain response distribution measurement unit 22 measures the time change in the vibration frequency distribution in the longitudinal direction of the optical fiber F based on the time change in the scattered light intensity distribution in the longitudinal direction of the optical fiber F (step S2).

[0028] Then, the underground facility position comparison unit 23 estimates the underground facility state of the optical fiber F (steps S4, S5) based on whether the time change in the vibration frequency distribution in the longitudinal direction of the optical fiber F is continuous or discontinuous over the longitudinal distance of the optical fiber F (step S3), and associates the underground facility position of the optical fiber F with the longitudinal distance of the optical fiber F (step S6).

[0029] Alternatively, the underground facility position comparison unit 23 estimates the underground facility state of the optical fiber F (steps S4, S5) based on whether the time change in the vibration frequency distribution in the longitudinal direction of the optical fiber F matches or does not match the time change in the vibration frequency of the earthquake vibration (step S3), and corresponds the underground facility position of the optical fiber F to the longitudinal distance of the optical fiber F (step S6).

[0030] A specific example of the optical communication underground facility position comparison process of the first embodiment is shown in Fig. 4. When an optical fiber F is laid under the ground G, it is laid in a pipeline T, connected by a closure C under a manhole M1, and passes through a manhole M2 without using the closure C.

[0031] In the vicinity of longitudinal distances of 1320 m, 1380 m, and 1460 m of the optical fiber F, the time change in the vibration frequency of the optical fiber F shows vibration attenuation of about 10 seconds at a high frequency of about 10 Hz, and vibration persistence of about 30 seconds at a low frequency of about 1 Hz. In other words, the time change in the longitudinal vibration frequency distribution of the optical fiber F is continuous over the longitudinal distance of the optical fiber F (step S3, YES). Alternatively, the time change in the longitudinal vibration frequency distribution of the optical fiber F coincides with the time change in the vibration frequency of earthquake vibrations (step S3, YES). This is because the optical fiber F is in contact with the ground G via the pipe T.

[0032] Therefore, the underground equipment position comparison unit 23 estimates that the underground equipment state of the optical fiber F is a section of the pipeline T in the vicinity of longitudinal distances of 1320 m, 1380 m, and 1460 m of the optical fiber F (step S5), and can correspond the position of the pipeline T to the vicinity of longitudinal distances of 1320 m, 1380 m, and 1460 m of the optical fiber F (step S6).

[0033] Only in the vicinity of a longitudinal distance of 1340 m of the optical fiber F, the time change in the vibration frequency of the optical fiber F shows a vibration continuation of about 30 seconds at a high frequency of about 10 Hz, and does not show any vibration at a low frequency of about 1 Hz. Only in the vicinity of a longitudinal distance of 1420 m of the optical fiber F, the time change in the vibration frequency of the optical fiber F shows no vibration at a high frequency of about 10 Hz, and shows a vibration delay of about 30 seconds at a low frequency of about 1 Hz. In other words, the time change in the longitudinal vibration frequency distribution of the optical fiber F is discontinuous over the longitudinal distance of the optical fiber F (step S3, NO). Alternatively, the time change in the longitudinal vibration frequency distribution of the optical fiber F does not match the time change in the vibration frequency of the earthquake vibration (step S3, NO). This is because the optical fiber F is not in contact with the ground G in the manholes M1 and M2.

[0034] Therefore, the underground facility position comparison unit 23 estimates that the underground facility state of the optical fiber F is the section of the manhole M1 where the closure C exists only in the vicinity of the longitudinal distance 1340 m of the optical fiber F (step S4), and can associate the position of the manhole M1 where the closure C exists with the vicinity of the longitudinal distance 1340 m of the optical fiber F (step S6).Then, the underground facility position comparison unit 23 estimates that the underground facility state of the optical fiber F is the section of the manhole M2 through which the optical fiber F passes only in the vicinity of the longitudinal distance 1420 m of the optical fiber F (step S4), and can associate the position of the manhole M2 through which the optical fiber F passes with the vicinity of the longitudinal distance 1420 m of the optical fiber F (step S6).

[0035] In this way, the positions of the sections of manholes M1, M2 and the sections of pipeline T, etc., can be associated with the longitudinal distance of optical fiber F based on whether the change over time in the longitudinal vibration frequency distribution of optical fiber F is continuous or discontinuous over the longitudinal distance of optical fiber F.

[0036] On the other hand, the positions of the sections of manholes M1, M2 and the sections of pipeline T, etc. can be associated with the longitudinal distance of optical fiber F based on whether the time change in the longitudinal vibration frequency distribution of optical fiber F coincides with or does not coincide with the time change in the vibration frequency of earthquake vibrations.

[0037] (Procedure for processing to compare the location of underground optical communication facilities in the second embodiment) The procedure of the underground optical communication facility position comparison process of the second embodiment is shown in Fig. 5. The scattered light intensity distribution acquisition unit 21 acquires information on the time change in the scattered light intensity distribution in the longitudinal direction of the optical fiber F when earthquake vibrations are applied to the optical fiber F laid underground (step S11). The strain response distribution measurement unit 22 measures the time change in the strain amplitude distribution in the longitudinal direction of the optical fiber F based on the time change in the scattered light intensity distribution in the longitudinal direction of the optical fiber F (step S12).

[0038] Then, the underground facility position comparison unit 23 estimates the underground facility state of the optical fiber F (steps S14, S15) based on whether the time change in the longitudinal strain amplitude distribution of the optical fiber F is continuous or discontinuous over the longitudinal distance of the optical fiber F (step S13), and associates the underground facility position of the optical fiber F with the longitudinal distance of the optical fiber F (step S16).

[0039] A specific example of the optical communication underground facility position comparison process of the second embodiment is shown in Fig. 6. When an optical fiber F is laid under the ground G, it is laid in a pipeline T, connected by a closure C under a manhole M1, and passes through a manhole M2 without using the closure C.

[0040] In the middle of Fig. 6, the time change in the strain amplitude distribution in the longitudinal direction of optical fiber F is shown in the range of 100nε to -100nε with the color scale of the strain amplitude set to full scale. In the lower part of Fig. 6, the time change in the strain amplitude distribution in the longitudinal direction of optical fiber F is shown in the range of 5nε to -5nε with the color scale of the strain amplitude set to an expanded scale.

[0041] In the vicinity of longitudinal distances of 1320 m, 1380 m, and 1460 m of optical fiber F, the time change in the longitudinal strain amplitude distribution of optical fiber F is continuous over the longitudinal distance of optical fiber F (step S13, YES). This is because optical fiber F is in contact with the ground G via the duct T. In the vicinity of a longitudinal distance of 1440 m of optical fiber F, the time change in the longitudinal strain amplitude distribution of optical fiber F is continuous over the longitudinal distance of optical fiber F (step S13, YES), but has a smaller strain amplitude. This is because optical fiber F is not in close contact with the duct T and has weak contact with the ground G.

[0042] Therefore, the underground facility position comparison unit 23 estimates that the underground facility state of the optical fiber F is a section of the pipeline T in the vicinity of the longitudinal distances of 1320 m, 1380 m, and 1460 m of the optical fiber F (step S15), and can associate the position of the pipeline T with the vicinity of the longitudinal distances of 1320 m, 1380 m, and 1460 m of the optical fiber F (step S16).Then, the underground facility position comparison unit 23 estimates that the underground facility state of the optical fiber F is a section of the pipeline T where the optical fiber F is not in close contact in the vicinity of the longitudinal distance of 1440 m of the optical fiber F (step S15), and can associate the position of the pipeline T where the optical fiber F is not in close contact with the vicinity of the longitudinal distance of 1440 m of the optical fiber F (step S16).

[0043] Only in the vicinity of a longitudinal distance of 1,340 m of the optical fiber F, the time change in the longitudinal strain amplitude distribution of the optical fiber F is discontinuous over the longitudinal distance of the optical fiber F and has a high-frequency strain amplitude (step S13, NO). This is because the optical fiber F is not in contact with the ground G in the manhole M1 and is connected by the closure C. Only in the vicinity of a longitudinal distance of 1,420 m of the optical fiber F, the time change in the longitudinal strain amplitude distribution of the optical fiber F is discontinuous over the longitudinal distance of the optical fiber F and has almost no strain amplitude (step S13, NO). This is because the optical fiber F is not in contact with the ground G in the manhole M2 and only passes through the manhole M2 without using the closure C.

[0044] Therefore, the underground facility position comparison unit 23 estimates that the underground facility state of the optical fiber F is the section of the manhole M1 where the closure C exists only in the vicinity of the longitudinal distance 1340 m of the optical fiber F (step S14), and can associate the position of the manhole M1 where the closure C exists with the vicinity of the longitudinal distance 1340 m of the optical fiber F (step S16).Then, the underground facility position comparison unit 23 estimates that the underground facility state of the optical fiber F is the section of the manhole M2 through which the optical fiber F passes only in the vicinity of the longitudinal distance 1420 m of the optical fiber F (step S14), and can associate the position of the manhole M2 through which the optical fiber F passes with the vicinity of the longitudinal distance 1420 m of the optical fiber F (step S16).

[0045] In this way, the positions of the sections of manholes M1, M2 and the sections of pipeline T, etc., can be associated with the longitudinal distance of optical fiber F based on whether the time change in the longitudinal strain amplitude distribution of optical fiber F is continuous or discontinuous over the longitudinal distance of optical fiber F. [Industrial Applicability]

[0046] The optical communications underground facility location comparison system, optical communications underground facility location comparison method, and optical communications underground facility location comparison device disclosed herein can reduce human operating rates by utilizing seismic vibrations to correspond the underground optical fiber facility location to the longitudinal distance of the optical fiber. [Explanation of symbols]

[0047] S: Underground facility location comparison system F: Optical fiber B: Optical communication building G: Ground M, M1, M2: Manhole C: Closure T: Pipeline 1: Scattered light intensity distribution measuring device 2: Underground facility location comparison device 21: Scattered light intensity distribution acquisition section 22: Distortion response distribution measurement section 23: Underground facility location comparison section

Claims

1. a scattered light intensity distribution measuring device for measuring a time change in a scattered light intensity distribution in a longitudinal direction of an underground laid optical fiber when an earthquake vibration is applied to the optical fiber; an underground facility position comparison device that measures a time change in a longitudinal strain response distribution of the optical fiber based on a time change in a longitudinal scattered light intensity distribution of the optical fiber, estimates an underground facility state of the optical fiber based on the time change in the longitudinal strain response distribution of the optical fiber, and associates an underground facility position of the optical fiber with a longitudinal distance of the optical fiber; An optical communication underground facility location comparison system comprising: The underground facility position comparison device measures a time change in a vibration frequency distribution in the longitudinal direction of the optical fiber based on a time change in a scattered light intensity distribution in the longitudinal direction of the optical fiber, estimates an underground facility state of the optical fiber based on whether the time change in the vibration frequency distribution in the longitudinal direction of the optical fiber is continuous or discontinuous over a longitudinal distance of the optical fiber, and associates an underground facility position of the optical fiber with a longitudinal distance of the optical fiber. An optical communication underground facility location comparison system.

2. a scattered light intensity distribution measuring device for measuring a time change in a scattered light intensity distribution in a longitudinal direction of an underground laid optical fiber when an earthquake vibration is applied to the optical fiber; an underground facility position comparison device that measures a time change in a longitudinal strain response distribution of the optical fiber based on a time change in a longitudinal scattered light intensity distribution of the optical fiber, estimates an underground facility state of the optical fiber based on the time change in the longitudinal strain response distribution of the optical fiber, and associates an underground facility position of the optical fiber with a longitudinal distance of the optical fiber; An optical communication underground facility location comparison system comprising: The underground facility position comparison device measures a time change in a vibration frequency distribution in the longitudinal direction of the optical fiber based on a time change in a scattered light intensity distribution in the longitudinal direction of the optical fiber, estimates a state of the underground facility of the optical fiber based on whether the time change in the vibration frequency distribution in the longitudinal direction of the optical fiber matches or does not match a time change in the vibration frequency of the earthquake vibration, and associates the underground facility position of the optical fiber with a longitudinal distance of the optical fiber. An optical communication underground facility location comparison system.

3. a scattered light intensity distribution measuring device for measuring a time change in a scattered light intensity distribution in a longitudinal direction of an underground laid optical fiber when an earthquake vibration is applied to the optical fiber; an underground facility position comparison device that measures a time change in a longitudinal strain response distribution of the optical fiber based on a time change in a longitudinal scattered light intensity distribution of the optical fiber, estimates an underground facility state of the optical fiber based on the time change in the longitudinal strain response distribution of the optical fiber, and associates an underground facility position of the optical fiber with a longitudinal distance of the optical fiber; An optical communication underground facility location comparison system comprising: The underground facility position comparison device measures a time change in a strain amplitude distribution in the longitudinal direction of the optical fiber based on a time change in a scattered light intensity distribution in the longitudinal direction of the optical fiber, estimates an underground facility state of the optical fiber based on whether the time change in the strain amplitude distribution in the longitudinal direction of the optical fiber is continuous or discontinuous over a longitudinal distance of the optical fiber, and associates an underground facility position of the optical fiber with a longitudinal distance of the optical fiber. An optical communication underground facility location comparison system.

4. a scattered light intensity distribution acquisition step of acquiring information on a time change in scattered light intensity distribution in a longitudinal direction of an underground laid optical fiber when an earthquake vibration is applied to the optical fiber; a strain response distribution measuring step of measuring a time change in a strain response distribution in the longitudinal direction of the optical fiber based on a time change in a scattered light intensity distribution in the longitudinal direction of the optical fiber; an underground facility position comparison step of estimating an underground facility state of the optical fiber based on a time change in a longitudinal strain response distribution of the optical fiber, and correlating an underground facility position of the optical fiber with a longitudinal distance of the optical fiber; A method for comparing the location of an optical communication underground facility, comprising the steps of: The underground facility location comparison step includes measuring a time change in a vibration frequency distribution in the longitudinal direction of the optical fiber based on a time change in a scattered light intensity distribution in the longitudinal direction of the optical fiber, and estimating a state of the underground facility of the optical fiber based on whether the time change in the vibration frequency distribution in the longitudinal direction of the optical fiber is continuous or discontinuous over the longitudinal distance of the optical fiber, and correlating the underground facility location of the optical fiber with the longitudinal distance of the optical fiber.

5. a scattered light intensity distribution acquisition step of acquiring information on a time change in scattered light intensity distribution in a longitudinal direction of an underground laid optical fiber when an earthquake vibration is applied to the optical fiber; a strain response distribution measuring step of measuring a time change in a strain response distribution in the longitudinal direction of the optical fiber based on a time change in a scattered light intensity distribution in the longitudinal direction of the optical fiber; an underground facility position comparison step of estimating an underground facility state of the optical fiber based on a time change in a longitudinal strain response distribution of the optical fiber, and correlating an underground facility position of the optical fiber with a longitudinal distance of the optical fiber; A method for comparing the location of an optical communication underground facility, comprising the steps of: The underground facility location comparison step includes measuring a time change in a vibration frequency distribution in the longitudinal direction of the optical fiber based on a time change in a scattered light intensity distribution in the longitudinal direction of the optical fiber, and estimating a state of the underground facility of the optical fiber based on whether the time change in the vibration frequency distribution in the longitudinal direction of the optical fiber matches or does not match the time change in the vibration frequency of the earthquake vibration, and correlating the underground facility location of the optical fiber with the longitudinal distance of the optical fiber.

6. a scattered light intensity distribution acquisition step of acquiring information on a time change in scattered light intensity distribution in a longitudinal direction of an underground laid optical fiber when an earthquake vibration is applied to the optical fiber; a strain response distribution measuring step of measuring a time change in a strain response distribution in the longitudinal direction of the optical fiber based on a time change in a scattered light intensity distribution in the longitudinal direction of the optical fiber; an underground facility position comparison step of estimating an underground facility state of the optical fiber based on a time change in a longitudinal strain response distribution of the optical fiber, and correlating an underground facility position of the optical fiber with a longitudinal distance of the optical fiber; A method for comparing the location of an optical communication underground facility, comprising the steps of: The underground facility location comparison step includes measuring a time change in a strain amplitude distribution in the longitudinal direction of the optical fiber based on a time change in a scattered light intensity distribution in the longitudinal direction of the optical fiber, and estimating a state of the underground facility of the optical fiber based on whether the time change in the strain amplitude distribution in the longitudinal direction of the optical fiber is continuous or discontinuous over the longitudinal distance of the optical fiber, and correlating the underground facility location of the optical fiber with the longitudinal distance of the optical fiber.

7. a scattered light intensity distribution acquisition unit that acquires information on a time change in a scattered light intensity distribution in a longitudinal direction of an underground laid optical fiber when an earthquake vibration is applied to the optical fiber; a strain response distribution measurement unit that measures a time change in a strain response distribution in the longitudinal direction of the optical fiber based on a time change in a scattered light intensity distribution in the longitudinal direction of the optical fiber; an underground facility position comparison unit that estimates an underground facility state of the optical fiber based on a time change in a longitudinal strain response distribution of the optical fiber and associates an underground facility position of the optical fiber with a longitudinal distance of the optical fiber; An optical communication underground facility position comparison device comprising: The underground facility position comparison unit measures a time change in a vibration frequency distribution in the longitudinal direction of the optical fiber based on a time change in a scattered light intensity distribution in the longitudinal direction of the optical fiber, estimates an underground facility state of the optical fiber based on whether the time change in the vibration frequency distribution in the longitudinal direction of the optical fiber is continuous or discontinuous over a longitudinal distance of the optical fiber, and associates an underground facility position of the optical fiber with a longitudinal distance of the optical fiber. An optical communication underground facility position comparison device characterized by the above.

8. a scattered light intensity distribution acquisition unit that acquires information on a time change in a scattered light intensity distribution in a longitudinal direction of an underground laid optical fiber when an earthquake vibration is applied to the optical fiber; a strain response distribution measurement unit that measures a time change in a strain response distribution in the longitudinal direction of the optical fiber based on a time change in a scattered light intensity distribution in the longitudinal direction of the optical fiber; an underground facility position comparison unit that estimates an underground facility state of the optical fiber based on a time change in a longitudinal strain response distribution of the optical fiber and associates an underground facility position of the optical fiber with a longitudinal distance of the optical fiber; An optical communication underground facility position comparison device comprising: The underground facility position comparison unit measures a time change in a vibration frequency distribution in the longitudinal direction of the optical fiber based on a time change in a scattered light intensity distribution in the longitudinal direction of the optical fiber, estimates an underground facility state of the optical fiber based on whether the time change in the vibration frequency distribution in the longitudinal direction of the optical fiber matches or does not match a time change in the vibration frequency of the earthquake vibration, and associates the underground facility position of the optical fiber with a longitudinal distance of the optical fiber. An optical communication underground facility position comparison device characterized by the above.

9. a scattered light intensity distribution acquisition unit that acquires information on a time change in a scattered light intensity distribution in a longitudinal direction of an underground laid optical fiber when an earthquake vibration is applied to the optical fiber; a strain response distribution measurement unit that measures a time change in a strain response distribution in the longitudinal direction of the optical fiber based on a time change in a scattered light intensity distribution in the longitudinal direction of the optical fiber; an underground facility position comparison unit that estimates an underground facility state of the optical fiber based on a time change in a longitudinal strain response distribution of the optical fiber and associates an underground facility position of the optical fiber with a longitudinal distance of the optical fiber; An optical communication underground facility position comparison device comprising: The underground facility position comparison unit measures a time change in a strain amplitude distribution in the longitudinal direction of the optical fiber based on a time change in a scattered light intensity distribution in the longitudinal direction of the optical fiber, estimates an underground facility state of the optical fiber based on whether the time change in the strain amplitude distribution in the longitudinal direction of the optical fiber is continuous or discontinuous over a longitudinal distance of the optical fiber, and associates an underground facility position of the optical fiber with a longitudinal distance of the optical fiber. An optical communication underground facility position comparison device characterized by the above.

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