JP2011158343A - Exploration method of undiscovered sea-floor hydrothermal deposit and exploration system of undiscovered sea-floor hydrothermal deposit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently specify a position of sea-floor hydrothermal deposit present in the seabed. <P>SOLUTION: A sound tomography device 10 is used for observing change of seawater density based on information of transmission and reception of sound among two or more places of the seabed, a region where the change of seawater density produces is specified using the sound tomography device 10, it is estimated that a hydrothermal plume 42 is present in the region, an autonomous underwater vehicle (AUV) 30 is moved to the region, the state of sea water is measured using the autonomous underwater vehicle 30, the hydrothermal plume 42 flowing from the sea-floor hydrothermal deposit 40 is detected based on the measurement results, a region where the hydrothermal plume 42 is detected is determined as a position of the sea-floor hydrothermal deposit 40. According to such a method, the sea-floor hydrothermal deposit can be efficiently explored, which allows, for example, the reduction in profit margin costs when metal resources of the sea-floor hydrothermal deposit are used. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a search method for an undiscovered submarine hydrothermal deposit and an exploration system for an undiscovered submarine hydrothermal deposit.

  It is known that submarine hydrothermal deposits exist in the seas near Japan, such as the Izu Ogasawara area and the Okinawa area. Undersea hydrothermal deposits are seawater that has penetrated deep underground and is heated by the heat of magma, etc., and is ejected to the seabed, in which heavy metals such as gold, silver, copper, lead, and zinc in hot water are precipitated. It is. This submarine hydrothermal deposit is expected as a supply source of new metal mineral resources, and is an important resource for Japan, which has been considered to be blessed with resources.

  In general, a submarine hydrothermal deposit is generated by the following process. First, seawater that has penetrated into the crust is heated by underground magma, and in the process of reacting with the host rock, heavy metals are added from the mother rock into the seawater, and gas components such as hydrogen sulfide, carbon dioxide, methane, etc. from the magma Is also added directly to acquire the properties of hot water. Hot water that has acquired heavy metals and hydrogen sulfide has buoyancy when heated and pressurized to near the critical point, and rises to the bottom of the sea. Hot water that rises to the bottom of the sea and erupts into the sea rises to a certain depth, and then spreads sideways. A smoke-like water mass made of hot water in this way is called a hot water plume. The hydrothermal plume shows abnormal values in the concentration of various chemical components compared to the surrounding seawater.

  The hot water plume mixes with the low temperature, alkaline and oxidative surrounding seawater at the bottom of the sea, and its properties change. In this process, the solubility of metal sulfides is lowered, and sulfide precipitates such as copper sulfide and iron sulfide are generated and become the foundation of the seafloor hydrothermal deposit.

  FIG. 1 shows such a circulation of seawater → heating by magma → ejection of hot water. As shown in the figure, the above-mentioned submarine hydrothermal deposit has (1) the initial stage of the activity when the heat source from the magma 44 is transmitted and the circulation starts, (2) the mid-activity period in which the circulation continues actively and the submarine hydrothermal deposit grows ( 3) It is formed through the process of the end of the activity where the circulation stops and the growth of the submarine hydrothermal deposits ends. The seabed hydrothermal deposit in the early days of activity is in a state where chimneys have begun to form. The submarine hydrothermal deposit in the middle of the activity is in a state where the heavy metal in the hydrothermal plume 42 is precipitated and growing, and the submarine hydrothermal deposit in the end of the activity is in a state where the growth has stopped due to the stop of hot water ejection. It is.

  As a technique of using such a submarine hydrothermal deposit as a metal supply source, there is one that collects a suspension itself in a hot water plume (see, for example, Patent Document 1). However, it is a natural premise that such a technique must grasp the location of the submarine hydrothermal deposit.

  Here, there are various methods for specifying the location of the submarine hydrothermal deposit. For example, there is a method of detecting a hydrothermal plume that flows out from the early stage to the middle stage of the activity of the submarine hydrothermal deposit. Specifically, the survey area is determined in advance, and the ship is towed with a remotely operated vehicle (ROV) or autonomous underwater vehicle (AUV), and various sensors mounted on the ROV and AUV. To observe the state of seawater. The seawater state is observed by measuring the seawater temperature and pH or by observing it with an imaging device. Based on this observation data, the presence or absence of a hot water plume is detected, and it is determined that a submarine hydrothermal deposit exists at a location where this hot water plume exists.

  However, in the search using the ROV as described above, the search range is limited because the speed is as low as about 1 knot, and a human operation is required. Further, in the survey of the sea area by AUV, the navigation speed of the AUV is as low as several knots, and it is difficult to design a route for maintaining the safety of navigation. After all, in the search by these ROVs and AUVs, for example, it is difficult to investigate a wide sea area ranging from several hundred to several tens of kilometers, and there is a problem that it takes a long time for the investigation.

  By the way, carbon capture and storage (CCS: Carbon Capture and Storage) that collects carbon dioxide emitted from factories and power plants, etc., and stores it in the seabed underlayer has been proposed. ROV and AUV are also used for investigation. In the case of this CCS, since the place where underground storage is performed is known, the area where carbon dioxide leaks is limited to some extent, and thus the above-described problem does not become apparent. However, it is difficult to narrow down the location of the submarine hydrothermal deposit in advance, as in the case of CCS, and it is necessary to conduct a wide-range survey. Therefore, there is a technology for more effectively identifying the location of the submarine hydrothermal deposit. It has been demanded.

  In this way, if it takes time to identify the location of the submarine hydrothermal deposit, it will ultimately increase the cost of collecting metals from the submarine hydrothermal deposit, and it will not be profitable. There is a risk that it will not be possible.

In addition, it is known that microorganisms using chemical substances such as CH ₄ , CO, H ₂ S, and H ₂ inhabit in a high temperature, high pressure, oxygen-free hot water plume. These microorganisms are considered to be active from the middle to the last stage of activity, and it is predicted that the species and habitat distribution of microorganisms will be changed according to the environmental change of the seafloor hydrothermal deposit. When investigating such microorganisms from an academic point of view, it is assumed that the location of the submarine hydrothermal deposit is identified, so it is desirable to identify the location of the submarine hydrothermal deposit as soon as possible. It is.

  Furthermore, considering the observation of living organisms in the vicinity of hydrothermal water erupting from the seabed, minerals are not collected when hot water is erupting from the beginning of the activity to the middle of the activity, and minerals are collected at the end of the activity. It may be desirable. In view of such circumstances, it is necessary to grasp the state of the formation process of the submarine hydrothermal deposit.

Japanese Patent Laid-Open No. 5-256082

  In view of such circumstances, the present invention is a method for exploring an undiscovered submarine hydrothermal deposit and an undiscovered exploration system for an undiscovered submarine hydrothermal deposit capable of efficiently specifying the position of a submarine hydrothermal deposit present on the seabed. The purpose is to provide.

  In order to achieve the above object, a first aspect of the present invention uses an acoustic tomography technique for observing a change in seawater density based on information on sound transmission / reception between a plurality of locations on the seabed, and the acoustic tomography technique. Identify the area where the seawater density change occurs, estimate that a hot water plume is present in the area, move the underwater moving means comprising measuring means for measuring the state of seawater to the area, Let the underwater transportation means measure the state of seawater, detect the hot water plume flowing out from the seafloor hydrothermal deposit based on the measurement result, and make the area where the hydrothermal plume was detected be the location of the seafloor hydrothermal deposit It is in the exploration method of the undiscovered submarine hydrothermal deposit characterized by

  In such a first aspect, an area where the hydrothermal plume is present is estimated from a wide area of the sea using acoustic tomography technology, and thereafter, the area is investigated by an underwater moving means, and the presence of the submarine hydrothermal deposit is detected. Specify the position. Thus, since the area | region where a hot water plume exists is narrowed down from the sea area covering a wide range by the investigation by acoustic, the underwater moving means can investigate within the limited area. Thereby, the existence position of a submarine hydrothermal deposit can be specified efficiently.

  According to a second aspect of the present invention, in the method for exploring an undiscovered seafloor hydrothermal deposit described in the first aspect, the acoustic tomography technique is used to measure a change in seawater temperature over a predetermined period of time, An undiscovered method for exploring an undiscovered submarine hydrothermal deposit characterized by estimating the process of formation of a submarine hydrothermal deposit from precipitation of heavy metals contained in hot water erupted from the seabed based on the change in seawater temperature. is there.

  In the second aspect, it is possible to estimate the process of forming the seafloor hydrothermal deposit from the change in seawater temperature. That is, it can be estimated whether the formation of the seafloor hydrothermal deposit is in the initial stage, the intermediate stage, or the final stage. Thereby, for example, a submarine hydrothermal deposit in a state where the ejection of hot water has ended can be found and the mineral can be mined. In addition, by discovering submarine hydrothermal deposits in the early and middle stages of activity where hot water is erupting, we will prepare for future mineral collection, while observing organisms that inhabit the erupting hot water. It is possible to maintain the seafloor hydrothermal deposit in that state.

  According to a third aspect of the present invention, in the method for exploring an undiscovered submarine hydrothermal deposit described in the first or second aspect, the measurement of the state of the seawater is selected from the group consisting of metal, pH, and turbidity. It is an exploration method for an undiscovered submarine hydrothermal deposit, characterized in that at least one of them is measured. As a measuring method, it is carried out by on-site measurement with a chemical sensor or analysis by collecting seawater.

  In the third aspect, it is possible to specify the presence of a hot water plume by detecting metals or the like and observing the collected seawater.

  According to a fourth aspect of the present invention, a change in seawater density occurs based on a plurality of acoustic tomography devices installed on the seabed so as to be able to transmit and receive sound to each other, and information on sound transmission and reception by the acoustic tomography devices. A submarine hydrothermal deposit estimating means that estimates that a submarine hydrothermal deposit is present in the area and an underwater moving means having a measuring means for measuring the state of seawater, The means measures the state of the seawater with the measuring means while navigating the area, detects the seafloor hot water plume flowing out from the seafloor hydrothermal deposit based on the measurement result, and detects the seafloor hydrothermal plume. Is an undiscovered submarine hydrothermal deposit exploration system characterized by the location of the submarine hydrothermal deposit.

  In the fourth aspect, an area where the hydrothermal plume is present is estimated from a wide area of the sea using acoustic tomography technology, and thereafter, the area is investigated by the underwater moving means, and the presence of the submarine hydrothermal deposit is detected. Specify the position. Thus, since the area | region where a hot water plume exists is narrowed down from the sea area covering a wide range by the investigation by acoustic, the underwater moving means can investigate within the limited area. Thereby, the existence position of a submarine hydrothermal deposit can be specified efficiently.

  ADVANTAGE OF THE INVENTION According to this invention, the search method of the undiscovered seafloor hydrothermal deposit which can identify the position of the seafloor hydrothermal deposit which exists in the seabed efficiently, and the search system of an undiscovered seafloor hydrothermal deposit are provided.

It is a conceptual diagram which shows the formation process of a seabed hydrothermal deposit. It is the schematic which shows the positional relationship of the acoustic tomography apparatus arrange | positioned on the seabed and a hot-water plume. 1 is a schematic configuration diagram of an undiscovered submarine hydrothermal deposit exploration system according to an embodiment of the present invention. It is an external view of an acoustic transmission / reception means (underwater acoustic device). It is a schematic block diagram of a no-submarine.

  Hereinafter, the best mode for carrying out the present invention will be described.

<Embodiment 1>
As shown in FIG. 2, as described above, seawater enters the crust, the seawater is heated by magma, ejected into the sea, and a hot water plume 42 is formed from the ejected hot water. From the hot water plume 42, heavy metals contained therein are precipitated to form a seabed hydrothermal deposit. A chimney 41 protruding into the sea is formed near the hot water outlet. As shown in FIG. 3, the existence position of the submarine hydrothermal deposit 40 is used to estimate the existence position of the undiscovered submarine hydrothermal deposit exploration system 1, that is, the acoustic tomography device 10 and the hydrothermal plume 42. The identification using the processing device (seafloor hydrothermal deposit estimation means) and the unsearched submersible machine 30 and the searchable submersible machine 60 which are underwater moving means will be described.

  The acoustic tomography apparatus 10 is for detecting the hot water plume 42 using the acoustic tomography technique. Specifically, a plurality (five in the illustrated example) of acoustic tomography apparatuses 10a, 10b, 10c, 10d, and 10e are installed on the seabed in a sea area where the presence of a seabed hydrothermal deposit is expected. The sea area is as wide as several hundred to several tens of kilometers. Each of the acoustic tomography devices 10a to 10e is installed in a state where the absolute position and the relative position of each other are grasped by GPS or the like.

  As shown in FIG. 4, the acoustic tomography apparatus 10 includes a sound source including a transceiver 12 that transmits and receives sound of a predetermined frequency, a power supply device, a control device that controls these sound source and power supply devices, and the like in a container 11. It is provided and configured. The container 11 is fixed to the frame 13 and is installed on the seabed via the frame 13 in a state where the transmitter / receiver 12 is turned up, that is, in a state where sound can be transmitted and received over the entire circumference of 360 degrees.

  Moreover, as shown in FIG. 2, the control means 14 is installed in the seabed. The control means 14 is connected to each acoustic tomography apparatus 10a-10e.

  The control unit 14 includes a CPU, a storage unit, and an input / output device, transmits a control signal for transmitting sound to the acoustic tomography devices 10a to 10e, and receives data from the acoustic tomography devices 10a to 10e. Record in storage means.

  By operating the acoustic tomography apparatuses 10 a to 10 e and the control unit 14 having such a configuration for a predetermined period, data for a predetermined period is accumulated in the storage unit of the control unit 14. The data stored in the control means 14 is processed by an information processing device (not shown).

  More specifically, the five acoustic tomography devices 10a to 10e emit sound from the transceiver 12 to the other four devices at the same time based on the control signal from the control means 14, and the other four devices. The sound from the apparatus is received by the transceiver 12. The received data is transmitted to the control means 14 and recorded in the storage means of the control means 14. After executing such an operation for a predetermined period, the data recorded in the storage means of the control means 14 is collected and processed by the information processing apparatus.

  When hot water is ejected into the sea to form the hot water plume 42, the seawater density changes due to changes in the pH of the seawater due to the hot water plume 42, changes in the temperature of the seawater, changes in salinity, changes in the physical properties of the liquid, and the like. Due to the change in the density of the seawater, a difference occurs in the propagation time of sound transmission / reception between the acoustic tomography apparatuses 10b and 10d, and further in the propagation time of sound transmission / reception between the acoustic tomography apparatuses 10c and 10e. There is a difference. The information processing apparatus can estimate the position of the region 50 by analyzing the situation of these time differences.

  By analyzing the difference in sound propagation time measured by the acoustic tomography devices 10a to 10e, the temperature in the sea can be calculated, so the temperature change of the seawater over a predetermined period may be observed. Based on this temperature change, it can be estimated in which state the formation process of the seafloor hydrothermal deposit 40 as shown in FIG. 1 is.

  As shown in FIG. 1, when the formation process of the seafloor hydrothermal deposit 40 is in the early stage of the activity, since the hot water has just spouted from the seabed, the seawater temperature tends to rise. Therefore, when the temperature change observed with the acoustic tomography apparatuses 10a to 10e tends to increase, it can be estimated that the formation process of the submarine hydrothermal deposit 40 is in the initial stage of activity.

  When the formation process of the seafloor hydrothermal deposit is in the middle of the activity, the seawater temperature near the seafloor hydrothermal deposit 40 is higher than the surrounding temperature, but the temperature change is not large. Therefore, when the temperature change observed with the acoustic tomography apparatuses 10a to 10e is substantially constant, it can be estimated that the formation process of the submarine hydrothermal deposit 40 is in the middle of activity.

  When the formation process of the seafloor hydrothermal deposit 40 is at the end of the activity, the hot water jet from the seabed stops, so the seawater temperature tends to decrease. Therefore, when the temperature change observed with the acoustic tomography apparatuses 10a to 10e is in a downward trend, it can be estimated that the formation process of the seafloor hydrothermal deposit 40 is at the end of the activity.

  Thus, the process in which the seabed hydrothermal deposit 40 is formed can be estimated from the change in the seawater temperature. That is, it can be estimated whether the formation of the seafloor hydrothermal deposit 40 is in the initial stage of activity, the middle period of activity, or the last stage of activity. Thereby, for example, the submarine hydrothermal deposit 40 in a state where the ejection of hot water is finished can be found and the mineral can be mined. In addition, by discovering the seafloor hydrothermal deposit 40 in the early and middle stages of activity where hot water is erupting, we prepare for future mineral collection, while observing organisms that inhabit the erupting hot water In addition, it is possible to maintain the subsea hydrothermal deposit 40 in that state.

  As shown in FIG. 3, after the region 50 where the hot water plume 42 exists is estimated by the acoustic tomography technique, the state of the seawater in the region 50 is scrutinized using the unlined submersible 30 or the roped submersible 60. To do.

  Specifically, as shown in FIG. 5, a no-submersible 30 having a measuring unit 31 and a storage medium 32 in which measurement data measured by the measuring unit 31 is recorded is used. The no-submarine 30 is a submarine (AUV: Autonomous Underwater Vehicle) that operates autonomously without any search. The navigator 30 measures the state of seawater with the measuring means 31 while navigating the area 50, and stores the measurement data as a storage medium 32. It is configured to record.

  The measuring means 31 is various sensors, pH sensors, and thermometers that detect radioactive substances such as metals, metal compounds, carbon compounds, and radon that are unique to the hot water plume 42. In addition, the measuring unit 31 may be a water intake unit that collects the hot water plume 42 in order to measure a chemical component of the hot water plume 42 collected from the region 50 in the vicinity of the chimney 41. Further, the measuring means 31 may be an imaging device, and the hot water plume 42 ejected through an image obtained from the imaging device may be detected visually.

After the measurement in the area 50, the measurement data recorded in the storage medium 32 of the unsearched submersible 30 is analyzed. In general, the hot water plume 42 contains metals and the like, for example, Mn, Fe, gas components, and the like, for example, CH ₄ and CO ₂ at a concentration higher than the concentration in seawater. Therefore, it can be specified that the hot water plume 42 exists in the region 50 by detecting a high concentration of metal or the like from the measurement data. And as mentioned above, since the precipitate of sulfide is formed by mixing the hydrothermal plume 42 and the surrounding seawater to form the seafloor hydrothermal deposit 40, it can be specified that the seafloor hydrothermal deposit 40 exists in the region 50. it can.

  Thus, after searching the area | region 50 with the unsearched diving machine 30, you may search with the cabled diving machine 60 further. The roped submersible 60 is a submarine (ROV: Remotely Operated Vehicle) that is connected to the mother ship 61 with a cable 62 and navigates by cable under the control of the mother ship 61. In addition, the cabled submersible 60 is provided with various measuring means like the cableless submersible 30. Under the control of the mother ship 61, the roped submersible 60 performs measurement by the measuring means in the region 50 and sends the result to the mother ship 61 via the cable 62. Then, in the same manner as the analysis of the measurement result by the measuring means of the unsearched submersible 30 described above, the mother ship 61 analyzes the data measured by the measuring means of the roped submersible 60, and in the region 50, the high concentration metal The region where the above is detected is specified as the location of the hot water plume 42, that is, the seabed hydrothermal deposit 40.

  As described above, the region 50 where the hot water plume 42 is estimated to be present is specified by the acoustic tomography technique, and the unsealed submersible device 30 and the searchable submersible device 60 indicate the state of the seawater in the region 50. Measurement is performed, and the location of the submarine hydrothermal deposit 40 is specified based on the measurement data.

  Here, it is not appropriate for the unsearched submersible device 30 and the searchable submersible device 60 to investigate a wide sea area. This is because the time and cost required for the unsearched submersible device 30 and the searchable submersible device 60 to survey a wide sea area increase. On the other hand, the acoustic tomography apparatus 10 can set a survey range of 100 km square or more, and can estimate the region 50 where the hot water plume 42 exists from a wide range of sea areas.

  Therefore, after the area 50 is first identified using the acoustic tomography apparatus 10, the area 50 is measured by the unsearched submersible device 30. The search efficiency by the unsearched submersible 30 can be improved.

  Further, the roped submersible 60 is controlled by the mother ship 61 via the cable 62, and the navigation range is limited for convenience of transmitting measurement data to the mother ship 61. However, since the acoustic tomography devices 10a to 10e and the unsearched submersible device 30 specify the region 50 prior to the investigation by the roped submersible 60, the search for the submersible 60 is limited to the region 50. This makes it possible to more efficiently locate undiscovered seafloor hydrothermal deposits 40.

  As described above, in the undiscovered submarine hydrothermal deposit exploration system 1 of the present invention, the presence of the hydrothermal plume 42 can be detected in a wide range of sea areas by the acoustic tomography technique. Can be done efficiently.

  As described above, since the location of the submarine hydrothermal deposit 40 can be searched efficiently, the cost required to identify the location of the submarine hydrothermal deposit 40 can be reduced. This also leads to an improvement in profitability when the submarine hydrothermal deposit 40 is used as a source of resources such as metals, and is greatly applied to the practical use of utilizing metal resources from the submarine hydrothermal deposit 40. Contribute.

  Furthermore, according to the present invention, the submarine hydrothermal deposit 40 can be efficiently explored, and therefore the location of the submarine hydrothermal deposit 40 can be specified at an early stage from the generation of the submarine hydrothermal deposit 40. Therefore, it is also possible to observe from an early stage the aspect of microorganisms that are considered to change according to the formation process of the seafloor hydrothermal deposit 40.

<Other embodiments>
As the frequency of the sound used by the acoustic tomography apparatus 10, sounds having a plurality of different frequencies may be used. The acoustic tomography device 10 generates a sound and receives the sound to identify a region where the density change of the seawater occurs. Generally, the higher the frequency of the sound, the more sensitively detects the density change of the seawater. can do. Therefore, the region where the hot water plume 42 exists is estimated for each sound having a plurality of different frequencies, and the region where the hot water plume estimated for each sound is present. If they match, the probability that a hot water plume exists can be estimated to be higher.

  In addition, the acoustic tomography apparatus 10 does not need to send data to the information processing apparatus 20 in real time. Each acoustic tomography apparatus 10 includes a data storage unit, and separately analyzes data in a predetermined period to perform a hydrothermal plume. You may identify the area | region where 42 exists. It is also possible to detect discontinuous changes over time by detecting the presence of the hot water plume 42 in units of days, weeks, months, and years.

  The control means 14 is connected to the information processing apparatus 20 of the monitoring station 21 to exchange information. However, the control means 14 and the acoustic tomography apparatus 10 are equipped with a large-capacity power source and are not connected by a cable or the like. It is also possible to exchange information with the acoustic tomography apparatus 10 by wireless communication. In this case, in order to synchronize the time at which each acoustic tomography device 10 transmits sound, each acoustic tomography device 10 is provided with synchronization means such as an atomic clock.

  INDUSTRIAL APPLICABILITY The present invention can be used in the industrial field for efficiently detecting a seafloor hydrothermal deposit.

DESCRIPTION OF SYMBOLS 1 Exploration system 10, 10a, 10b, 10c Acoustic tomography apparatus 11 Container 12 Transceiver 13 Frame 14 Control means 20 Information processing apparatus 21 Monitoring station 30 Unequaled submersible 31 Measuring means 32 Storage medium 40 Submarine hydrothermal deposit 41 Chimney 42 Hydrothermal plume 44 Magma 50 Region 60 Rope submersible

Claims (4)

Using acoustic tomography technology that observes changes in seawater density based on information on the transmission and reception of sound between multiple locations on the seabed, identify the region where the change in seawater density occurs in the acoustic tomography technology, and Presumed that there was a hot water plume,
Move underwater moving means equipped with measuring means for measuring the state of seawater to the area, let the underwater moving means measure the state of seawater, and detect the hot water plume flowing out from the seafloor hydrothermal deposit based on the measurement result An undiscovered method for exploring an undiscovered seafloor hydrothermal deposit, wherein an area where the hydrothermal plume is detected is defined as an existing position of the seafloor hydrothermal deposit. In the method for exploring an undiscovered submarine hydrothermal deposit according to claim 1,
For the region, a change in seawater temperature is measured over a predetermined period by the acoustic tomography technology, and a seafloor hydrothermal deposit is formed by precipitation of heavy metals contained in the hot water ejected from the seabed based on the seawater temperature change. An undiscovered method for exploring undiscovered submarine hydrothermal deposits, characterized by estimating the processes performed. In the exploration method of the undiscovered seafloor hydrothermal deposit according to claim 1 or claim 2,
The measurement of the state of the seawater is to measure at least one selected from the group consisting of metal, pH and turbidity. A plurality of acoustic tomography devices installed on the seabed so that sound can be transmitted and received between each other;
A seafloor hydrothermal deposit estimator that estimates that a seafloor hydrothermal deposit is present in the area by identifying the area in which the seawater density change occurs based on information on transmission and reception of sound by the acoustic tomography device; ,
An underwater moving means having a measuring means for measuring the state of seawater,
The underwater moving means measures the state of seawater with the measuring means while navigating the area, detects a submarine hydrothermal plume flowing out from the submarine hydrothermal deposit based on the measurement result, and detects the submarine hydrothermal plume. A search system for undiscovered submarine hydrothermal deposits, characterized in that the detected area is the location of the submarine hydrothermal deposits.

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