JP3808861B2 - Seafloor observation system - Google Patents

Description

  The present invention relates to a system for observing the seabed by detecting physical changes directly or indirectly obtained from the seabed, such as physical phenomena occurring on the seabed or reflected waves of waves intentionally transmitted toward the seabed.

  Monitoring crustal movements, exploring marine resources, or preserving the marine environment is extremely beneficial, and it is increasingly important today for Japan, an island nation. In recent years, various seafloor observations have been made due to these demands, but surveys over a wide area are necessary, and even if it is a powerful technology on the ground, it cannot be brought into the seafloor as it is, There is a problem that it is extremely difficult to install various measuring instruments, and it is said that enormous costs are required for seabed observation. In particular, in the seismic observation at the sea floor, the observation may be performed by measuring the refracted wave or the reflected wave by an artificial earthquake such as an air gun or blasting with a submarine seismometer. More specifically, the submarine seismometer used for this seismic observation includes an observation sensor in a spherical enclosure, a recorder for recording a signal output from the sensor, a floating portion for levitating the device, and an external device. An anchor that is separated by the acoustic signal is connected to a submarine seismometer that includes a separation control device that receives the specific acoustic signal to perform anchor separation control and a battery that drives these devices. The A plurality of submarine seismometers constructed in this way are loaded on the hull, the hull is operated and anchored at a target observation point, and the submarine seismometers suspended in a sling with wires are observed from the ship The operation is carried out at a plurality of observation points at appropriate intervals, such as dropping to the target seabed, fixedly installed on the seabed with a connected anchor, and disconnecting the wire from the seafloor seismometer. In this way, one submarine seismometer is installed at each of a plurality of observed points, and after that, an artificial earthquake is caused from a predetermined location and is mounted on the submarine seismometers installed at each observed point. Measure with a sensor and record the result on the built-in recorder. After that, a predetermined acoustic signal is transmitted to each submarine seismometer to operate the separation control device, and the submarine seismometer is separated from the anchor that has been fixed to the seabed to self-float and the seafloor that has surfaced on the sea surface. Submarine earthquake observations are made by collecting seismometers one by one, disassembling each collected submarine seismometer and extracting the information recorded in the recorder. The term “sea” used in this specification is a general term for the sea, rivers, lakes, swamps, ponds, and the like.

  In the case of submarine seismic observation using this method, when the submarine seismometer is dropped into the sea, the submarine seismometer that is connected and supported only from the ship is submerged into the sea where there is a tidal current. In addition, since the submarine seismometer and the wire that suspends the seismometer are pushed against the tidal current, it is difficult to match the dropping position with the installation position, resulting in a large error. In order to stabilize each submarine seismometer, it is necessary to make the submarine seismometer itself heavy. There are multiple observation points, and it is necessary to load several submarine seismometers in order to cope with them. This requires a lot of work time and the total loading capacity becomes very large. In addition, the installed submarine seismometer does not have a shipboard station and cannot perform real-time observation. Furthermore, this submarine seismometer is independent of the hull and is independent of each other, and since it has a built-in battery, it cannot be observed for a period exceeding the battery life and cannot be used for long-term observation. Submarine seismometers must be collected once at a time. When collecting them, the anchors must be separated and left on the seabed, and the anchors cannot be reused. When a submarine seismometer is levitated, it is swept away by tidal currents in the middle of the ascent, making it difficult to predict the ascent point and contributing to the difficulty of recovery. In order to float, it is necessary to obtain a buoyancy sufficient to lift the housing containing the sensor, recorder, separation control device, battery, etc. Therefore, the housing requires a considerable size and becomes very bulky. End up. Furthermore, if the submarine seismometer is not disassembled, the information recorded in the recorder cannot be taken out, and reusing the submarine seismometer requires reassembly and enormous effort, making it impossible to reuse the anchor. There was a problem that a new anchor had to be connected every time and a very high cost was required.

  In addition, as another seafloor observation device, a cable type that is configured by connecting a plurality of detection units for detecting a physical phenomenon on the seabed in series via an optical fiber cable and attached to the seabed is used. Submarine observation devices and terminal devices installed on the ground or on land that receive optical signals transmitted from the detectors arranged at each point of this series of cables and process those signals. A constructed seabed observation device is disclosed. A typical example is the technique disclosed in Japanese Patent No. 2814976. The technology disclosed in this patent uses a one-way optical fiber cable that is folded back, and the information obtained at each observation point is output as a signal on a unique wavelength on the outgoing cable, and the return side has multiple waves. The signal passes through each point through and is returned to the land station, and each detection unit is composed only of an optical demultiplexer and an optical multiplexer that are optical devices, and an electric circuit is unnecessary, The detection unit is configured not to require a power supply unit. According to this technique, each detection unit does not require a power supply unit, and since sufficient consideration is given to simplification of the apparatus and the problem of heat generation by an electric circuit, this type of problem can be solved. However, in this case, although real-time observation is possible, it has not been studied to operate in the desired sea area with the hull and obtain observation data on the seabed in the desired sea area or process the observation data. There is a problem.

Another example of a cable-type seabed observation apparatus using an optical fiber cable as described above is the seabed observation apparatus disclosed in Japanese Patent Laid-Open No. 10-107702. According to the contents disclosed in this gazette, it is possible to use the communication submarine optical cable for seabed observation by incorporating the seabed observation device in the repeater of the submarine optical cable conventionally used for communication. Become. However, in this case, the area where the seafloor can be observed has been the observation target only in the area where the optical submarine optical cable for communication that has been attached to the seabed or will be newly attached in the future, or other places, or There is a difficulty in not being able to conduct surveys and observations in any sea area.
Japanese Patent No. 2814976 JP-A-10-107702

  The present invention has been made in view of the conventional problems as described above. The purpose of the present invention is to allow installation and recovery in an arbitrary sea area while utilizing a laying method or a recovery method similar to the submarine cable laying. It is possible to provide a seafloor observation system that can be used repeatedly and that can be either temporary or permanent, and can perform highly accurate observations economically.

  The present invention provides a plurality of detection units each having an observation sensor for detecting a physical phenomenon occurring on the seabed, and a signal transmission unit for transmitting an output signal of the sensor, and the detection units are spaced apart from each other at a predetermined interval. Are connected in series and mounted on a ship that receives the optical signal obtained through the optical fiber cable, and an optical fiber cable that serves as a transmission medium for the optical signal transmitted from the signal transmitting means. A cable-type observation device, a hull for loading this cable-type observation device, dropping it into the sea while moving and laying it on the desired seabed, and confirming the current position of the hull And a position confirmation means mounted on the hull for the purpose of identifying the specific detection unit among a plurality of detection units, and assigning a unique signal to each detection unit in advance as identification information, The detection unit of When dropping from the ship to the point to be observed at the point, the position information obtained from the position confirmation means at each drop point is associated with the identification information of the detection unit to be dropped, and this is used as initial information to the marine apparatus. A series of cable-type observation devices equipped with a plurality of detection units were laid on the sea floor while being recorded and obtained from at least identification information output from each detection unit and each observed point at the time of observation. By associating the occasional information including the observation information with the initial information recorded in advance, it is possible to simultaneously and in real time observe the seabed at each observation point at any time after laying. It is characterized by that.

  The position confirmation means is a position confirmation device for confirming a current position by GPS.

  The unique signal is assigned in advance so that the optical signal transmitted from the detection unit has a different wavelength depending on the detection unit, or a unique name is assigned to each detection unit in advance to include the name. It is characterized in that the signal is used as identification information so that it can be distinguished from other observation devices.

  The cable-type seabed observation device has an end of an optical fiber cable connected to a side opposite to the side to which the offshore device is connected, and one end of an idle cable is extended and an anchor is provided at the other end of the idle cable. Composed.

  By using a cable-type observation device, the present invention enables permanent installation or repetitive installation and recovery in a desired sea area, and enables observation of a plurality of observation points simultaneously and in real time. At the same time, the observation information obtained by the cable-type observation device and the position information obtained by the GPS can be associated with each other, so that high-precision observation can be performed.

  In addition, if it is intended to be permanently installed like a conventional cable-type seafloor observation device, it will require a long-term water pressure resistance around the detector, resulting in an increase in cost. According to the present invention, since it can be used as a temporary installation, there is an effect that the cost of such an apparatus itself can be increased and the costs associated with its transportation and installation can be reduced.

A preferred embodiment of the present invention will be described below in detail with reference to the drawings. FIG.
FIG. 2 is a schematic diagram showing a method for laying and lifting a cable-type observation device according to the present invention, and FIG. FIG. 4 is a block diagram showing an example of a signal system in the cable type observation apparatus according to the present invention. As shown in FIG. 1, the seafloor observation method of the present embodiment is desired by an observation ship (2) for laying and measuring the cable-type observation apparatus (1) according to the present invention, and the observation ship (2). A series of cable-type observation devices (1) formed by connecting a plurality of detection units (5) laid in advance on the survey side line before the earthquake at predetermined intervals, and the cable-type observation devices A seismic ship (3) for emitting sound waves toward the seabed at a desired sea level in the sea area where (1) is laid, and an air gun (4) which is an acoustic exploration means by the seismic ship (3) ) Is transported to the first earthquake location (P1), and the air gun (4) is operated to oscillate, and the refracted waves of the waves are provided in the detectors (5) laid at each observation point. The seismometer (6) respectively senses the observation result sensed by the seismometer (6) as an optical signal, and the observation ship (2) through the optical fiber cable (7) To the offshore device (8) placed on the surface, and obtain the observation results at each observation point in the offshore device (8), then transport the air gun (4) to the second earthquake location (P2). Then, operate the air gun (4) again, and in the same way as in the case of the first earthquake, obtain the observation results at each observed point in the marine device (8), and so on to the desired earthquake location (P). It is configured to be able to perform seismic motion while moving sequentially and analyze and analyze those observation results.

  In the above refraction method, depending on the seismometer (6) interval and water depth, in the case of seabed observation of the trench near the Japanese archipelago using the device of this example, in order to ensure sound pressure above a certain level, It is preferable to use an air gun with a capacity of 000 cu or more. For example, an air gun (4) can be used on the extension of the side line of the section where the seismometer (6) is installed, for example, from 100 nautical miles to 100 nautical miles on the opposite side of the side line ), And the sounding interval of the air gun (4) is set to 100 m as a result.

  In addition to the air gun (4), a well-known technique, apparatus, or method can be used as a vibration source for the earthquake in the refraction method. For example, blasting can be used. When using blasting, blasting 500 kg of dynamite at a point of 100 nautical miles on the extension line of the side line, a point up to 100 nautical miles on the extension line on the opposite side of the side line, and a point between them at intervals of 150 km, It is preferable to perform blasting using 250 kg of dynamite at 50 km intervals.

  In addition, when the seafloor observation system using the sound wave survey having the above-described configuration is used, it is possible to perform the seabed observation by the reflection sound wave sound search as well as the refraction sound wave sound search. When the seafloor observation is performed by this reflection method sound wave survey, for example, an air gun (4) can be used as the sound source, and an air gun (4) having a capacity of 6,000 cu or more in order to ensure a sound pressure above a certain level. Preferably, the air gun (4) is sounded at intervals of 50 m from a point 10 nautical miles on the extension line of the side line to 10 nautical miles on the extension line on the opposite side of the side line. Of course, the capacity of the air gun (4), the amount of dynamite, or the distance and interval of sound generation may be set to desired values and are not limited at all. In addition, in order to correct the sound wave data in seawater for further refinement, it is desirable to measure the water temperature and salinity at appropriate intervals and collect the data.

  The seismic vessel (3) can use one or a plurality of vessels, and as described above, the seismic location may be changed and the seismic location may be changed at the same time. May be. When the sound wave survey by the refraction method or the reflection method as described above is performed simultaneously on a plurality of observation ships (2) and the seismic ship (3), the distance between the side lines should be separated by 800 km or more to avoid mutual interference of sound waves. It is preferable to carry out.

  Hulls such as the observation ship (2) and the seismic ship (3) are not particularly limited, but in order to carry out the survey efficiently, the cable-type observation device (1) is laid and lifted, It is preferable to divide the seismic work such as air gun work, blasting work, etc. into specialized hulls respectively, the observation ship (2) is used for laying and lifting work of the cable type observation device (1), air gun work, blasting work, etc. The seismic work (3), such as an air gun work ship and a blast work ship, can be assigned to each seismic work. The observation ship (2) can be arbitrarily selected according to the survey scale, but preferably a submarine cable laying ship is used. Submarine cable laying ships can use hulls with known facilities that are conventionally used when laying submarine cables, space where personnel can board, hullability and hull strength suitable for equipment, Equipped with a hull with a wide and low deck suitable for workability, a winch for laying and lifting the cable-type observation device (1), and a positioning system capable of continuous precise sea positioning More preferably, it is equipped with a device capable of accurately measuring and profiling water temperature and salinity in seawater.

  The seismic vessel for air gun operation (3) has a space where personnel can be boarded, a hull with a wide and low deck suitable for serviceability, hull strength suitable for equipment, workability, and air gun loading / unloading. It is equipped with a seized A-type frame crane, a large-capacity air gun system composed of an air gun, a compressor, and the like, and a positioning system capable of performing continuous precise sea positioning, and more preferably the water temperature in seawater And equipped with a device that can accurately measure and profile salinity.

  Seismic ships for blasting work include a space where personnel can be boarded, hulls with a wide and low deck suitable for seaworthiness, equipment suitable for equipment, workability, and special containers for storing explosives. , A dynamite A-type frame crane and winch, and a positioning system capable of continuously performing precise marine positioning, more preferably in seawater Equipped with a device that can accurately measure and profile water temperature and salinity.

  Next, a procedure for laying and lifting the cable type observation apparatus (1) according to the present invention will be described with reference to FIG. A plurality of detectors (5) each provided with a seismometer (6) are connected in series via an optical fiber cable (7) to form a series of cable bodies, and an idle cable (9) is connected to one end of the cable body. A cable type observation device (1) formed by connecting one end, fixing a marshmallow anchor (10) to the other end of the idle cable (9), and connecting the other end of the cable body to a marine device (8). Is operated to the end of the survey line, and the winch is operated in the deployment direction, The marshmallow anchor (10) attached to the tip of the cable type observation device (1) is dropped toward the seabed, and the marshmallow anchor (10) is semi-fixed to the seabed to end the end of the cable type observation device (1). The first seismometer (6) is installed along with the fixed point. To. At this time, the position confirmation means for confirming the sea position by GPS placed on the observation ship (2) obtains the position information of the installation point of the seismometer (6) in the first ground, Corresponding identification information for identifying one seismometer (6) is recorded in the offshore device (8). The cable-type observation device (1) was laid while operating the observation ship (2) along the positioning line, and the second seismometer (6) was installed at the next seismometer (6) drop point. Each seismometer (8) is installed on the seabed, and the identification information for identifying the second seismometer (6) is associated with the position information from the GPS and recorded in the marine device (8). A series of cable-type observation devices (1) are laid on the desired survey line while associating 6) with the information on the installation position.

  As described above, the marshmallow anchor (10), which is the first semi-fixed point, is placed at the tip of the cable-type observation device (1) and installed at the very beginning of the laying so that the marshmallow anchor (10 ) After installation, since it is laid in order with support from below installed semi-fixed on the seabed and support from above with cables connected from the hull, that is, while receiving support from above and below, Unlike conventional seismometers, seismometers (6) can be installed without any deviation from the target point, even if there are tidal currents. In other words, the installation position information of a certain seismometer (6) obtained from the position confirmation means is given as a good approximation for the place where the seismometer (6) is actually installed on the seabed, and high accuracy Can be obtained.

  And after the bottom of the final seismometer (6), the cable-type observation device (1) is further laid over an appropriate distance, for example, the entire line of 50 to 300 km. Hold and observe the artificial earthquake by the earthquake vessel (3). After the observation, the cable type observation device (1) can be collected. Of course, the installed cable type observation device (1) may be used while maintaining the installed state for a long time depending on the purpose or the contents of observation, and the installation period is not limited at all. As shown in Fig. 2, the cable-type observation device (1) that has been laid is operated in the above-mentioned manner while synchronizing the speed of the laying route while traveling backward (traveling in the direction indicated by the arrow formed by the dotted frame). The winch is actuated in the winding direction, and the cable type observation device (1) is pulled up in the direction indicated by the dotted line arrow to be lifted. The cable-type observation device (1) that has been collected can be used repeatedly.

  As shown in FIG. 3, the cable-type observation device (1) according to the present invention has n detectors (5) each provided with one seismometer, every 3 km through an optical fiber cable (7). Are connected in series to form a series of cable bodies, one end of the idle cable (9) is connected to one end of the cable body, and the marshmallow anchor (10) is fixed to the other end of the idle cable (9). The other end of the cable body is connected to a marine device (8) for collecting and processing data.

  In the cable type observation apparatus (1) illustrated in FIG. 3, the length of the optical fiber cable (7) connecting the seismometers (6) is 3 km. 5) The length of the optical fiber cable (7) connecting the two can be set to a desired length and is not limited at all, but the analysis of the observation data may depend on the interpretation by the analyst. In addition, the distance is set so as not to increase the cost by making the interval too narrow, preferably 3 to 5 km.

  The idle cable (9) can have a desired length, but is, for example, 2 to 5 km, preferably 4 to 10 km. In this example, the length of the idle cable (9) is 5 km, which makes it easy to install the seismometer (6) and enables high-precision installation.

  The greater the weight of the marshmallow anchor (10), the more stable the tip of the cable-type observation device (1), but if it is too large, installation work and pick-up work will be difficult, and it will be loaded on the ship. If it is too small, it will not be stable and the tip will not be able to hold a fixed point, so the weight of the marshmallow anchor (10) will be The workability is good and the tip can be stabilized, preferably 0.1 to 2t, more preferably 1 to 2t. The weight of the marshmallow anchor (10) in this example is 1 ton, so that the workability of installation and lifting is good, and the tip of the cable type observation device (1) is strongly semi-fixed and stabilized. I can do it.

  The offshore device (8) receives the data observed by each seismometer (6) via the optical fiber cable (7) and accumulates and processes the data. ), The initial information stored in association with the position information and the identification information in advance and the occasional information obtained for each observation can be processed in association with each other. Of course, the marine apparatus may be placed on land as well as on the ship, and may be placed on an underwater ship such as a submarine.

  As shown in FIG. 4, the signal system of the cable-type observation device (1) in the present embodiment is a marine device (8) for collecting and processing data, and one at each of the n observed points. N detectors (5) installed one by one, an optical fiber cable (7) connecting these detectors (5), and a series of signal systems connecting these detectors (5) An optical fiber cable (7) connecting the marine apparatus (8).

  The seabed phenomenon detection unit (5) includes a seismometer (6) for detecting a submarine earthquake, and an A / D conversion means for converting an analog signal output from the seismometer (6) into a digital signal. (11), an earthquake data multiplexing means (12) for multiplexing and multiplexing the digital signal data converted and output by the A / D conversion means (11) of each seismometer (6), and electrical An electrical / optical conversion means (13) for converting the digital signal into an optical signal and transmitting the optical signal to the offshore apparatus (8) via an optical fiber cable, and transmitted from the offshore apparatus (8) From an optical / electrical conversion means (14) configured integrally with the electric / optical conversion means (13) for receiving an optical signal comprising position information and time information and converting it into an electrical signal; To control power supply to these A / D conversion means (11), earthquake data multiplexing means (12), electrical / optical conversion means (13), and optical / electrical conversion means (14) Power supply means (15).

  The seabed observation device (1) in the present embodiment is configured as described above, but a series of beaded observation devices by connecting a plurality of observation sensors capable of performing desired seabed observation The observation data obtained from the sensor can be transmitted as an optical signal to the offshore apparatus, and it is only necessary to be able to identify from which observation sensor the received signal is obtained. The structure and configuration of the detection unit (5) are not particularly limited. Therefore, a conventionally known technique can be used for the configuration of the sensor, the power feeding system, the optical system, or the electrical system. For example, as a power supply system, a battery may be built in the seabed phenomenon detection unit (5) as a power source, or the inside of the seabed phenomenon detection unit (5) is configured only from an optical system and is connected to the seafloor device (8). The optical system in the seabed phenomenon detection unit (5) may be controlled by an optical signal.

  The marine apparatus (8) includes a position confirmation means (16) for positioning by GPS, and a time confirmation means (17) capable of outputting time information as an optical signal while inputting position information from the position confirmation means (16). ), Optical / electrical conversion means (18) for receiving the optical signal from each detector (5) and converting the optical signal into an electrical signal, and the combined data converted into the electrical signal for each earthquake Individual data separation means (19) for separating and separating the total data into individual data, integration / processing control means (20) for controlling the collection and processing of the separated individual observation data, and this integration / processing control Recording means (21) for recording the individual observation data while being controlled by means (20), data monitoring means (22) capable of monitoring the recorded data, and the detection unit (5) Power supply device (23) for supplying power, and position information, time information and In addition, information processing can be performed while corresponding to information received from seismometers. As described above, the maritime apparatus (8) in the present embodiment is configured as described above, but information processing is performed while associating information from each seismometer (6) with position information and time information. The structure and configuration of the offshore device (8) are not particularly limited. The power output from the power supply device (23) is transmitted to the power supply means (15) disposed in each detection unit (5) via a power supply path (24) provided along with the optical fiber cable (7). It is configured to be able to.

  The seafloor observation system of this example is configured as described above, and the observation ship (2) mounted on the winch and equipped with the cable type observation device (1) is operated on the desired side line and synchronized with the traveling speed. While operating the winch in the deployment direction, lay the cable-type observation device (1) on the seabed and install the seismometers (6) located in each part of the cable-type observation device (1) at the observation point. . When installing each seismometer (6) at each observed point, the position confirmation means (16) that can be measured by the GPS mounted on the observation ship (2) is operated to install the seismometer (6). It was installed in correspondence with the identification information for distinguishing this position information from the other seismometers (6) assigned to each seismometer (6) in advance. The seismometer (6) and its installation location are recorded in the recording means (21) of the offshore device (8) as initial information. Perform this operation for all installed seismometers (6) so that the information from the seismometers (6) at any time after installation can be analyzed. Constitute. In this way, the cable-type observation device (1) was laid on the side line, and after laying the seismic vessel equipped with a sound probe such as an air gun (4) or dynamite for blasting, holding the observation ship at a fixed point in place (3) is operated in a predetermined sea area, and is sounded by using the sound wave exploration means for each predetermined position, so that the surrounding sea area is vibrated. Each seismometer (6) laid on the side line senses the waves generated by this earthquake, which vary depending on the seabed conditions and the sea area, and the observation information output from the seismometer (6) (6) An optical fiber cable to the detection unit (5) that is output from the detection unit (5) as an optical signal and located next to the side closer to the offshore device (8), including identification information for identifying (6) (7) is transmitted. In this way, the observation data output from each seismometer (6) is multiplexed one after another or sequentially transmitted, and finally the offshore device (8) placed on the observation ship (2). Is transmitted. The multiplexed observation data received by the offshore device (8) is separated into individual observation data and can be associated with the initial information recorded in advance, and the observation data obtained at any time can be recorded and analyzed. It is configured so that it can.

  The identification information only needs to be able to distinguish a specific seismometer (6) from other seismometers (6), and is unique to each detector (5) or seismometer (6) in advance. Signals can be assigned to provide identification information. As the unique signal, the optical signal transmitted from the detection unit (5) may be previously modulated by the detection unit (5) so as to have different amplitudes and frequencies and may be uniquely assigned to each, or may be configured in advance. Each detector (5) may have a unique name, and the signal including the name may be configured to be identified from other detectors (5) as identification information. In addition, it is possible to adopt a conventionally known technique or method. The seafloor observation system of the present embodiment is configured as described above, but is not limited to the acoustic exploration shown in this example, and can be applied to carry out desired seafloor observation, exploration, or survey. Is possible.

Schematic showing the seabed observation method when refraction acoustic survey is applied by applying the present invention Schematic showing the laying and lifting method of the cable type observation device according to the present invention The layout which shows the arrangement relation of each part of the cable type observation device concerning this invention The block diagram which shows an example of the signal system | strain in the cable type observation apparatus concerning this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cable type observation apparatus 2 Observation ship 3 Seismic ship 4 Air gun 5 Detection part 6 Seismometer 7 Optical fiber cable 8 Marine device 9 Idle cable 10 Marshmallow anchor 11 A / D conversion means 12 Earthquake data multiplexing means 13 Electrical / optical conversion Means 14 Optical / electrical conversion means 15 Power supply means 16 Position confirmation means 17 Time confirmation means 18 Optical / electrical conversion means 19 Individual data separation means 20 Integration / processing control means 21 Recording means 22 Data monitoring means 23 Power supply device 24 Power supply path

Claims (5)

A plurality of detection units each having an observation sensor for detecting a physical phenomenon occurring on the seabed and a signal transmission means for transmitting an output signal of the sensor, and the detection units are connected in series at a predetermined interval. An optical fiber cable connected to and serving as a transmission medium for an optical signal transmitted from the signal transmission means, and receiving the optical signal obtained through the optical fiber cable, and integrating the received data A cable-type observation device comprising: a marine device mounted on a ship for processing;
A hull for loading this cable-type observation device, moving it into the sea while moving, and laying it on the desired seabed,
Position confirmation means mounted on the hull for confirming the current position of the hull;
With
In order to identify a specific detection unit from among a plurality of detection units, a specific signal is assigned to each detection unit in advance as identification information,
When each detection unit is dropped from the ship to the observation point at a certain point in time, the position information obtained from the position confirmation means at each drop point is associated with the identification information of the detection unit to be dropped. A series of cable-type observation devices comprising a plurality of detection units are laid on the sea floor while recording the initial information on the marine device,
At the time of observation, laying is performed by associating at any time information including at least identification information output from each detection unit and observation information obtained from each observed point with the initial information recorded in advance. A seafloor observation system that can perform seafloor observation at each observation point at a later point in time simultaneously and in real time.   The seafloor observation system according to claim 1, wherein the position confirmation means is a position confirmation device for confirming a current position by GPS.   The submarine observation system according to claim 1 or 2, wherein the unique signal is assigned in advance so that the optical signal transmitted from the detection unit has a different wavelength and amplitude depending on the detection unit.   3. The unique signal is configured such that a unique name is assigned to each detection unit in advance, and the signal including the name can be identified from other observation devices as identification information. The described seafloor observation system. The cable type seafloor observation device is constructed by connecting one end of an idle cable to the end of the optical fiber cable opposite to the side where the offshore device is connected, and having an anchor at the other end of the idle cable. The seabed observation system according to claim 1 to 4.

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