CN106156874B - Tsunami prediction technique and device, tsunami early warning method and device - Google Patents

Abstract

The present invention provides tsunami prediction technique and device, tsunami early warning method and device.The tsunami prediction technique includes: data acquisition step, obtains the spatial data in tsunami progression region；Propagation time calculates step and calculates the propagation time between adjacent mesh and storage according to acquired data；Arrival time calculates step, according to the propagation time between adjacent mesh, obtain the arrival time of each grid in grid group to be selected, according to the minimum value of the arrival time of each grid in grid group to be selected, next step Source of Wavelets is selected from grid group to be selected, to calculate the arrival time that tsunami reaches each grid in tsunami progression region, wherein grid group to be selected is possible be as the set of the grid of Source of Wavelets；And output step, export the arrival time of each grid in tsunami progression region.In accordance with the invention it is possible to carry out quick tsunami prediction, early warning.

Description

Tsunami prediction method and device, tsunami warning method and device

technical field

The present invention relates to a tsunami prediction method and device, a tsunami early warning method and device, and in particular to a tsunami prediction method and device based on tsunami propagation time.

Background technique

Tsunamis usually cause heavy casualties and huge economic losses. Therefore, accurate prediction of the arrival time of the tsunami and timely early warning based on the tsunami prediction results can effectively reduce economic losses and casualties.

Currently, generally, the propagation process of a tsunami is analyzed by calculating the tsunami propagation time. Grid data of ocean depths are required to calculate the tsunami travel time.

In Non-Patent Document 1, it is considered from the viewpoint of kinematics that the propagation of a tsunami wave follows the Huygens principle. As a tsunami wave travels, each point on the wavefront can be considered a new point source.

The speed of tsunami waves in the ocean is approximately any two points on earth The formula for the distance between is:

where θ ₁ , θ ₂ are longitudes, is the latitude and R is the radius of the earth.

Let O be the wavelet source and A be the grid on the neighborhood of O, then the travel time from O to grid point A is

Thus, the propagation time of the wavelet source to any grid in its neighborhood can be calculated.

Since the ocean depth data is in the form of a rectangular grid, in this data format, each grid has an N×N neighborhood, and it is assumed that the grid on the wavefront as a wavelet source affects its N×N neighbors. area. For a grid on the N×N neighborhood of the wavelet source, if the arrival time via the wavelet source is less than the original time of the grid, the smaller time value is used to replace the grid time.

In Non-Patent Document 2, the tsunami wave is considered to be a shallow water wave and satisfies the shallow water wave equation, and the tsunami propagation time is calculated by solving the shallow water wave equation by the finite difference method.

Non-Patent Document 1: Shokin, Yu.I., Chubarov, L.B., Novikov, V.A., and Sudakov, A.N.: Calculations of Tsunami Travel Time Charts in the Pacific Ocean-Models, Algorithms, Techniques, Results, Sci. Tsunami Hazards, 5, 85 -122, 1987.

Non-patent document 2: I.V.Fine and R.E.Thomson.A wavefrontorientation method for precise numerical.determination of tsunami travel time.Nat.Hazards EarthSyst.Sci., 13, 2863-2870, 2013.

SUMMARY OF THE INVENTION

However, since the basic data used for tsunami prediction is very large, and the current method for calculating the arrival time of a tsunami is complicated and requires a large amount of computation, it requires a long computing time. Therefore, although it can be used for post-event analysis of a tsunami, it is difficult to use it for prediction of a tsunami immediately after an earthquake occurs at sea. In addition, it is difficult to perform tsunami prediction on an ordinary small computer. That is to say, it cannot meet the needs of disaster-responsible departments to quickly predict the spread of tsunamis and issue early warning information in a timely manner. In addition, disaster response departments need to be equipped with large-scale, special-purpose computing equipment, which requires a large investment.

Therefore, the present invention provides a fast tsunami prediction method. The tsunami prediction method can also be executed on an ordinary minicomputer.

A first aspect of the present invention provides a tsunami prediction method, the method includes: a data acquisition step of acquiring spatial data of a tsunami propagation area; a propagation time calculation step of calculating the distance between adjacent grids according to the acquired data Propagation time and storage; Arrival time calculation step, according to the propagation time between the adjacent grids, to obtain the arrival time of each grid in the grid group to be selected, according to the grid group to be selected The minimum value of the arrival time of the grid is selected, and the next wavelet source is selected from the candidate grid group, so as to calculate the arrival time of the tsunami reaching each grid in the tsunami propagation area, wherein the candidate grid A grid group is a collection of grids that may serve as wavelet sources; and an outputting step that outputs the time of arrival of each grid in the tsunami propagation area.

The present invention also provides a second mode, which is the tsunami prediction method according to the first mode, wherein, in the arrival time calculation step, for each wavelet source, the adjacent grids of the wavelet source are Add to the grid group to be selected, after selecting the next wavelet source, delete the grid that has been selected as the next wavelet source from the grid group to be selected, and repeat the above operations until there are no grids in the grid group to be selected .

The present invention also provides a third mode, which is the tsunami prediction method according to the first or second mode, wherein, in the arrival time calculation step, the arrival time is selected from the candidate grid group The grid with the smallest time is used as the next wavelet source.

The present invention also provides a fourth mode, which is the tsunami prediction method according to any one of the first to third modes, wherein the arrival time calculation step includes: an initialization step, which is configured to store A two-dimensional array of the arrival times of all grids in the tsunami propagation area, and initialized, the arrival times of all grids except the epicenter are initialized to an infinite value, and the epicenter is selected as the initial wavelet source; The grid group adding step is to put the adjacent grids of the wavelet source into the grid group to be selected, and read in the propagation time from the wavelet source to the adjacent grids stored in the propagation time calculation step; the arrival time is updated Step, when the arrival time of the adjacent grid is greater than the sum of the arrival time of the wavelet source and the propagation time from the wavelet source to the adjacent grid, update the arrival time at the adjacent grid to the sum value The next step of selecting a wavelet source is to select the grid with the minimum arrival time in the said grid group to be selected as the next wavelet source; the updating step of the grid group to be selected is to delete the grid group that has been selected as The grid of the wavelet source in the next step; when the number of grid groups to be selected is more than 1, repeat the steps of adding the grid groups to be selected, the update time of arrival step, the next step of selecting the wavelet source, and the grid to be selected. Group update steps.

The present invention also provides a fifth mode, which is the tsunami prediction method according to any one of the first or second mode, wherein, in the arrival time calculation step, according to all adjacent grids Between the minimum value of the propagation time and the minimum value of the arrival time in the candidate grid group, multiple grids are selected as the next wavelet source.

The present invention also provides a sixth mode, which is the tsunami prediction method according to any one of the first, second, and fifth modes, wherein the arrival time calculation step includes: an initialization step, setting A two-dimensional array for storing the arrival times of all grids in the tsunami propagation area, and initializing, initializing the arrival times of all grids except the epicenter to an infinite value, and selecting the epicenter as the initial wavelet source The minimum value calculation step calculates the minimum value of the propagation time between all adjacent grids; the grid group addition step to be selected puts the adjacent grid of this wavelet source into the grid group to be selected, reads Enter the propagation time from the wavelet source to the adjacent grid stored in the propagation time calculation step; in the arrival time update step, when the arrival time of the adjacent grid is greater than the arrival time of the wavelet source and from the wavelet source to the adjacent grid When the sum of the propagation times of , the arrival time at the adjacent grid is updated to the sum value; in the next step of wavelet source selection, according to the minimum value of the propagation time between all adjacent grids and the waiting time Select the minimum arrival time in the grid group, and select multiple grids as the next wavelet source; in the update step of the grid group to be selected, delete the grid that has been selected as the next wavelet source from the grid group to be selected ; When the number of the grid groups to be selected is more than 1, repeat the steps of adding the grid groups to be selected, updating the arrival time, selecting the next wavelet source, and updating the grid groups to be selected.

The present invention also provides a seventh mode, which is the tsunami prediction method according to the sixth mode, wherein, in the next step of selecting a wavelet source, the time of arrival is selected to be less than the difference between all adjacent grids. The grid of the sum of the minimum value of the propagation time and the minimum value of the arrival time in the candidate grid group is the next wavelet source.

The present invention also provides an eighth mode, which is the tsunami prediction method according to the fourth or sixth mode, wherein, in the step of adding the candidate grid group, only adjacent grids of the wavelet source are added. Among the grids, the grids located in the ocean and whose arrival time is greater than the arrival time of the wavelet source in the previous step are put into the candidate grid group.

The present invention also provides a ninth mode, which is the tsunami prediction method according to the first or second mode, wherein, in the propagation time calculation step, when the wavelet source is located on land, the The propagation time from the wavelet source to the adjacent grid is 0, or, when any one of the wavelet source and its adjacent grids is located on land, the propagation time from the wavelet source to the adjacent grid is set. is 0.

A tenth aspect of the present invention provides a tsunami early warning method, which is characterized by comprising: the tsunami prediction method according to any one of the first to ninth aspects; and an early warning step, according to the tsunami prediction method The result is output, and an early warning is issued for an area whose arrival time is less than a predetermined threshold.

An eleventh aspect of the present invention provides a tsunami prediction device, which is characterized by comprising: a data acquisition unit for acquiring spatial data of a tsunami propagation area; a propagation time calculation unit for calculating adjacent grids according to the acquired data The propagation time between the grids is stored; the arrival time calculation part obtains the arrival time of each grid in the grid group to be selected according to the propagation time between the adjacent grids, according to the grid group to be selected The minimum value of the arrival time of each grid, select the next wavelet source from the candidate grid group, so as to calculate the arrival time of the tsunami to each grid in the tsunami propagation area, wherein the The candidate grid group is a set of grids that may be used as wavelet sources; and an output unit that outputs the arrival time of each grid in the tsunami propagation area.

The present invention also provides a twelfth aspect, the twelfth aspect is the tsunami prediction device according to the eleventh aspect, wherein the arrival time calculation unit calculates, for each wavelet source, the adjacent grids of the wavelet source Add to the grid group to be selected, after selecting the next wavelet source, delete the grid that has been selected as the next wavelet source from the grid group to be selected, and repeat the above operations until there are no grids in the grid group to be selected .

The present invention also provides a thirteenth aspect, which is the tsunami prediction device according to the eleventh or twelfth aspect, wherein the arrival time calculation unit selects from the candidate grid group The grid with the smallest arrival time is used as the next wavelet source.

The present invention also provides a fourteenth aspect, which is the tsunami prediction apparatus according to any one of the eleventh to thirteenth aspects, wherein the arrival time calculation unit includes an initialization unit, Set up a two-dimensional array for storing the arrival times of all grids in the tsunami propagation area, and initialize, initialize the arrival times of all grids except the epicenter to an infinite value, and select the epicenter as the initial sub The wave source; the grid group addition part to be selected puts the adjacent grids of the wavelet source into the grid group to be selected, and reads the propagation time from the wavelet source to the adjacent grid stored in the propagation time calculation part ; the arrival time update part, when the arrival time of the adjacent grid is greater than the sum of the arrival time of the wavelet source and the propagation time from the wavelet source to the adjacent grid, the arrival time at the adjacent grid is updated as the sum value; the wavelet source selection part in the next step selects the grid with the smallest arrival time in the grid group to be selected as the wavelet source in the next step; the grid group update part to be selected deletes it from the grid group to be selected The grid that has been selected as the next wavelet source; when the number of grid groups to be selected is more than 1, the grid group addition part, the arrival time update part, the next wavelet source selection part, and the to-be-selected grid group are set. Select the mesh group update section to repeat the action.

The present invention also provides a fifteenth aspect, which is the tsunami prediction apparatus according to any one of the eleventh or twelfth aspect, wherein the arrival time calculation unit is based on all adjacent networks The minimum value of the propagation time between the grids and the minimum value of the arrival time in the grid group to be selected are selected, and multiple grids are selected as the next wavelet source.

The present invention also provides a sixteenth aspect, which is the tsunami prediction apparatus according to any one of the eleventh, twelfth, and fifteenth aspects, wherein the arrival time calculation unit includes : initialization part, setting a two-dimensional array for storing the arrival times of all grids in the tsunami propagation area, and initializing, initializing the arrival times of all grids except the epicenter to an infinite value, and selecting the epicenter is the initial wavelet source; the minimum value calculation part calculates the minimum value of the propagation time between all adjacent grids; the addition part of the grid group to be selected puts the adjacent grids of the wavelet source into the grid to be selected In the grid group, read the propagation time from the wavelet source to the adjacent grid stored in the propagation time calculation part; in the arrival time update part, when the arrival time of the adjacent grid is greater than the arrival time of the wavelet source and the time from the wavelet source to the When the sum of the propagation times of the adjacent grids is used, the arrival time at the adjacent grids is updated to the sum value; the next step, the wavelet source selection part, according to the propagation times between all adjacent grids and the minimum value of the arrival time in the grid group to be selected, select multiple grids as the next wavelet source; the update part of the grid group to be selected, delete from the grid group to be selected as the next step The grid of the wavelet source; when the number of grid groups to be selected is more than 1, make the grid group addition part to be selected, the arrival time update part, the next wavelet source selection part, and the grid group update part to be selected Repeat the action.

The present invention also provides a seventeenth mode. The seventeenth mode is the tsunami prediction device according to the sixteenth mode, wherein the next-step wavelet source selection unit selects an arrival time that is less than the difference between all adjacent grids. The grid of the sum of the minimum value of the propagation time and the minimum value of the arrival time in the candidate grid group is the next wavelet source.

The present invention also provides an eighteenth mode, which is the tsunami prediction device according to the fourteenth or sixteenth mode, wherein the candidate grid group adding part only adds adjacent ones of the wavelet sources Among the grids, the grids located in the ocean and whose arrival time is greater than the arrival time of the wavelet source in the previous step are put into the candidate grid group.

The present invention also provides a nineteenth aspect, which is the tsunami prediction device according to the eleventh or twelfth aspect, wherein the propagation time calculation unit causes the wavelet source to be located on land when the wavelet source is located on land. The propagation time from the wavelet source to the adjacent grid is 0, or, when any one of the wavelet source and its adjacent grids is located on land, the propagation time from the wavelet source to the adjacent grid is made. time is 0.

A twentieth aspect of the present invention provides a tsunami warning device, comprising: the tsunami prediction device according to any one of the eleventh to nineteenth aspects; The output result of the device issues an early warning to the area whose arrival time is less than a predetermined threshold.

According to the tsunami prediction method and device provided by the present invention, the arrival time of the tsunami arriving at each grid can be quickly obtained. That is, tsunami prediction can be performed quickly. Thus, a basis for timely early warning can be provided.

According to the tsunami early warning method and device provided by the present invention, early warning can be issued in time for the areas where the tsunami may reach. Thus, people in a potentially disaster-affected area are enabled to respond quickly to a disaster. Moreover, it can reduce casualties and economic losses.

In addition, the tsunami prediction method and device, and the tsunami early warning method and device provided by the present invention are simple in structure and small in calculation amount. Therefore, it can be applied to an ordinary small computer. Can reduce the cost of disaster response part.

Description of drawings

FIG. 1 is a diagram showing the main flow of the tsunami prediction method according to the first embodiment of the present invention;

Fig. 2 is a flow chart showing the specific steps of calculating the propagation time between adjacent grids;

FIG. 3 is a schematic diagram illustrating the propagation of a tsunami in a neighborhood;

FIG. 4 is a flowchart showing the specific steps of calculating the arrival time according to Example 1 of the first embodiment;

Fig. 5 is a flowchart showing the specific steps of calculating the arrival time involved in Example 2 of the first embodiment;

6 is a block diagram showing the main configuration of a tsunami prediction apparatus according to a second embodiment of the present invention;

7 is a block diagram showing the main configuration of the propagation time calculation module according to the second embodiment;

8 is a block diagram showing the main structure of the arrival time calculation module involved in Example 1 of the second embodiment;

9 is a block diagram showing the main configuration of a time-of-arrival calculation module according to Example 2 of the second embodiment;

10 is a graph showing the result of predicting the Chilean tsunami propagation time on April 2, 2014 based on the present invention;

11 is a diagram showing the main flow of the tsunami warning method according to the third embodiment;

12 is a block diagram showing a main configuration of a tsunami warning device according to a fourth embodiment.

Detailed ways

Hereinafter, specific embodiments of the present invention will be described in detail with reference to the accompanying drawings.

<First Embodiment>

First, the main flow of the tsunami prediction method according to the first embodiment of the present invention will be described with reference to FIG. 1 . The tsunami prediction method of the present invention includes: a data acquisition step S101, a propagation time calculation step S102, an arrival time calculation step S103, and an output step S104.

In the data acquisition step S101, spatial data of the tsunami propagation area is acquired.

Specifically, the spatial data of the tsunami propagation area refers to the data of the longitude, latitude, and depth of the tsunami propagation area.

In the prediction of tsunamis, spatial data of the area where the tsunami is likely to spread (ie, the tsunami propagation area) is required Longitude θ, Latitude Depth or elevation z. The spatial data can be given as a raster file or a text document. The units of longitude and latitude are decimal degrees, and the units of depth or elevation are meters.

If the grid is on land, the z-value is greater than or equal to 0, and if the grid is in the ocean, the z-value is less than 0. Due to the huge amount of ocean elevation data, it has a great impact on the calculation. Therefore, the spatial data can be simplified and the spatial resolution of the data can be reduced. By simplifying the spatial data, tsunami prediction can be performed on an ordinary minicomputer.

In the present invention, it is assumed that the number of rows and columns of grid data in the tsunami propagation area are row and column, respectively.

Next, in the propagation time calculation step S102, according to the acquired data, the propagation time between adjacent grids is calculated and stored. Regarding the specific calculation method of the propagation time, an existing method may be used, or a calculation method described later using FIG. 2 may be used.

In the present invention, the propagation time is the time for the tsunami to propagate between two adjacent grid points.

Next, in the arrival time calculation step S103, according to the propagation time between the adjacent grids stored in step S102, the arrival time of each grid in the grid group to be selected is obtained, according to the grid group to be selected. The minimum value of the arrival time of each grid is selected, and the next wavelet source is selected from the candidate grid group, so as to calculate the arrival time of the tsunami reaching each grid in the tsunami propagation area.

In the present invention, the grid group to be selected is a set of grids that may be used as wavelet sources, and the arrival time refers to the time when the tsunami reaches the grid from the source.

In step S103, for each wavelet source, add the adjacent grids of the wavelet source to the grid group to be selected, and after selecting the next wavelet source according to the above operation, delete the selected grid group from the grid group to be selected. For the grid of the next wavelet source, the above operations are performed cyclically until there is no grid in the grid group to be selected, so as to calculate the arrival time of the tsunami reaching each grid in the tsunami propagation area.

Finally, in the output step S104, the arrival time of each grid in the tsunami propagation area is output. The output can be output to an external storage device, an analysis device, an early warning device, a display device, a printing device, and the like. The output can be in the form of display, printing, storage, and so on. The output result can be a table or a graph. For example, as shown in FIG. 10 , in the geographic information system GIS, electronic map, etc., it is represented by the contour line of the arrival time.

<Calculation of propagation time>

Hereinafter, the above-mentioned propagation time calculation step S102 will be described in detail.

As shown in Figure 2, step S102 further includes: step S1021, calculating the distance between adjacent grids; step S1022, calculating the propagation speed of the tsunami wave along each grid; step S1023, according to the distance and the propagation speed speed, and calculate the propagation time; step S1024, store the propagation time data between the adjacent grids.

Specifically, in step S1021, the distance formula (1) between any two points on the earth can be used to calculate any grid O in the tsunami propagation area to points p ₁ , p ₂ ,... , the distance ρ(O, p _i ) between p ₁₆ .

In step S1022, the approximate relationship between the tsunami propagation speed and the ocean depth can be specifically Determine how fast the tsunami wave travels on each grid.

In step S1023, the propagation time between grid 0 and grids in the neighborhood is calculated.

As shown in Figure 3, in a rectangular grid, there is a grid of 4×4 neighborhoods. Note that the velocity of the grid where the point O is located is v, and the velocity of the grid where the point p _i (1≤i≤16) is located is v _i . Then the propagation time between O and p _i is

In step S1023, the following operations can also be performed: if the elevation of point O is greater than 0, let the propagation time from point O to the surrounding 16 points be 0; The propagation time between them is 0.

In step S1024, the propagation time between adjacent grids may be stored as new basic data. A grid with a 4×4 neighborhood in the elevation data has a total of nrow-2 rows and ncolumn-2 columns, which can store the travel time from each grid point to the 16 grid points in its neighborhood.

<Calculation of arrival time>

Hereinafter, the arrival time calculation step S103 will be described in detail.

Example 1

Hereinafter, Embodiment 1 of calculating the arrival time of the tsunami to each grid of the tsunami propagation area will be described with reference to FIG. 4 .

In Embodiment 1, step S103 includes: initialization step S1031 , adding a grid group to be selected S1032 , updating the arrival time S1033 , selecting the next wavelet source S1034 , and updating the grid group to be selected S1035 .

In the initialization step S1031, a two-dimensional array for storing the arrival times of all grids in the tsunami propagation area is set and initialized. The number of rows and columns of the two-dimensional array are row and column respectively. The element corresponding to the epicenter can be initialized to 0(s), and other elements can be initialized to infinite values, for example, it can be set to 10^8(s), and the epicenter is the initial wavelet source.

In the step S1032 of adding the grid group to be selected, the adjacent grids of the wavelet source are put into the grid group list to be selected, and the propagation from the wavelet source to the adjacent grid calculated and stored in the step S102 is read in time.

Specifically, among the propagation times between adjacent grids stored in step S1024, the grid of the wavelet source in this step and the grid adjacent to the wavelet source, that is, the wavelet source ( Propagation time between 16 grids p ₁ , p ₂ , . . . , p ₁₆ within the 4×4 neighborhood of i, j).

Also, if it hits land, the tsunami wave will not travel further. That is, tsunamis only propagate in the ocean. Therefore, only grids whose elevation z is less than 0 can be placed in the candidate grid group.

Moreover, in the present invention, for example, it is judged that the grid has not been put into the candidate grid group by the current arrival time t ₀ being greater than the arrival time min ₀ of the wavelet source in the previous step.

Therefore, in step S1032, only the adjacent grids of the wavelet source that are located in the ocean (z<0) and whose current arrival time is greater than the arrival time t ₀ >min ₀ of the wavelet source in the previous step can be placed into the grid to be in the grid group.

In the arrival time update step S1033, when the original arrival time _{t 0} of the adjacent grid pk is greater than the arrival time min ₁ of the wavelet source (i, _j ) and the propagation from the wavelet source to the adjacent grid pk When the sum of the times Δt _k , ie min ₁ +Δt _k <t ₀ , the arrival times at the adjacent grids are updated to the sum, ie t ₁ =min ₁ +Δt _k .

In the next step of selecting the wavelet source S1034, the grid with the smallest arrival time is selected as the next wavelet source in the list of the grid groups to be selected.

In step S1035 of updating the grid group to be selected, the grid that has been selected as the next wavelet source is deleted from the grid group list to be selected.

If the number of the grid group list to be selected is 1 or more, steps S1032 to S1034 are repeatedly executed.

According to the tsunami prediction method according to Example 1 of the first embodiment, by selecting a grid with the smallest arrival time from the candidate grid group as the next wave source, it is possible to quickly obtain the arrival of the tsunami to each grid. Time, can quickly predict the propagation process of tsunami, can provide a basis for timely early warning.

Example 2

Hereinafter, Embodiment 2 of calculating the arrival time of the tsunami to each grid of the tsunami propagation area will be described with reference to FIG. 5 .

In Embodiment 2, step S103 includes the next step of selecting a wavelet source S1034' to replace the next step of selecting a wavelet source S1034 in Embodiment 1, and may also include a minimum value calculation step S1030, and other steps are the same as those of Embodiment 1. same.

In the minimum value calculation step S1030, the minimum value Δt _min of the propagation time between all adjacent grids is calculated.

In FIG. 5, the minimum value calculation step S1030 is located after the initialization step S1031, however, the minimum value calculation step S1030 may also be located before the step S1031.

In addition, the minimum value of the propagation time between all adjacent grids can also be calculated and stored by other modules, and the minimum value Δt _min is directly used in the next wavelet source selection step S1034 ′. That is, the step S103 may not include the minimum value calculation step 1030, and the minimum value calculation step 1030 may be omitted.

In the next wavelet source selection step S1034', according to the minimum value Δt _min of the propagation time between all adjacent grids and the minimum value t _min of the arrival time in the grid group to be selected, multiple grids are selected as the next step wavelet source.

Specifically, in step S1034 ′, select a value whose arrival time is less than the sum of the minimum value Δt _min of the propagation time between all the adjacent grids and the minimum value t _min of the arrival time in the group of grids to be selected. The grid is the next wavelet source. That is, for any grid pk ( _1≤k≤n , where n is the length of the list) in the grid group to be selected, if the arrival time at grid _pk Then this grid is selected as the next wavelet source.

In Embodiment 2, if the number of grid groups to be selected is 1 or more, steps S1032 to S1033, S1034', and S1035 are repeatedly executed.

According to the tsunami prediction method involved in Embodiment 2, by selecting a batch of grids with smaller arrival times from the candidate grid group as the wave source of the next step, in addition to the same effect as Embodiment 1, it also has the advantages of better convergence Quick advantage. That is, the operation speed can be further improved. At the same time, the introduction of cumulative errors is avoided.

<Second Embodiment>

Hereinafter, a tsunami prediction apparatus according to a second embodiment of the present invention will be described with reference to FIG. 6 .

The tsunami prediction apparatus 1 of the present invention includes a data acquisition unit 101 , a propagation time calculation unit 102 , an arrival time calculation unit 103 , and an output unit 104 .

The data acquisition unit 101 acquires spatial data of the tsunami propagation area.

The data acquisition unit 101 may also perform simplified processing on the acquired spatial data to reduce the spatial resolution of the data.

The propagation time calculation unit 102 calculates and stores the propagation time between adjacent grids based on the acquired data.

The arrival time calculation unit 105 obtains the arrival time of each grid in the grid group to be selected according to the propagation time between adjacent grids stored by the propagation time calculation unit 102 , and obtains the arrival time of each grid in the grid group to be selected. The minimum value of the arrival time of the tsunami is selected, and the next wavelet source is selected from the grid group to be selected, so as to calculate the arrival time of the tsunami reaching each grid in the tsunami propagation area.

For each wavelet source, the arrival time calculation unit 103 adds the adjacent grids of the wavelet source to the grid group to be selected, and after selecting the next wavelet source according to the above operation, deletes the selected grid group from the grid group to be selected. For the grid of the next wavelet source, the above operations are performed cyclically until there is no grid in the grid group to be selected, so as to calculate the arrival time of the tsunami reaching each grid in the tsunami propagation area.

The output unit 104 outputs the arrival time of each grid in the tsunami propagation area. The output can be output to an external storage device, an analysis device, an early warning device, a display device, a printing device, and the like. The output can be in the form of display, printing, storage, and so on. The output result can be a table or a graph. For example, as shown in FIG. 10 , the output unit 104 is represented by a contour line of arrival time in a geographic information system GIS, an electronic map, or the like.

<Propagation Time Calculation Unit 102>

Hereinafter, the propagation time calculation unit 102 will be described in detail.

As shown in FIG. 7 , the propagation time calculation unit 102 includes a distance calculation unit 1021 , a speed calculation unit 1022 , a time calculation unit 1023 , and a propagation time storage unit 1024 .

The distance calculation unit 1021 uses the distance formula (1) between any two points on the earth to calculate the distance between any grid O in the tsunami propagation area and the points p ₁ , p ₂ , . . . , p ₁₆ in its neighborhood. Distance ρ(O, p _i ).

The velocity calculation unit 1022 uses the relational expression between velocity and ocean depth Determine how fast the tsunami wave travels on each grid.

The time calculation unit 1025 calculates the propagation time from the mesh O to the meshes in the neighborhood using the formula (3).

The time calculation unit 1025 can also perform the following operations: if the elevation of point O is greater than 0, set the propagation time from point O to the surrounding 16 points to be 0; The propagation time between is 0.

The propagation time storage unit 1024 stores the propagation time between adjacent meshes as new basic data.

<arrival time calculation unit 103>

Hereinafter, the arrival time calculation unit 103 will be described in detail.

Example 1

As shown in FIG. 8 , the arrival time calculation unit 103 includes: an initialization unit 1031 , a candidate grid group addition unit 1032 , an arrival time update unit 1033 , a next wavelet source selection unit 1034 , and a candidate grid group update unit 1035 .

The initialization section 1031 sets and initializes a two-dimensional array for storing the arrival times of all grids in the tsunami propagation area. The number of rows and columns of the two-dimensional array are row and column respectively. The element corresponding to the epicenter can be initialized to 0(s), and other elements can be initialized to infinite values, for example, it can be set to 10^8(s), and the epicenter is the initial wavelet source.

The candidate grid group adding unit 1032 puts the adjacent grids of the wavelet source into the candidate grid group list, and reads the propagation time from the wavelet source to the adjacent grid calculated and stored by the propagation time calculation unit 102 .

The grid group adding unit 1032 to be selected may also only place the grids located in the ocean (z<0) among the adjacent grids of the wavelet source and whose current arrival time is greater than the arrival time t ₀ >min ₀ of the wavelet source in the previous step. into the grid group to be selected.

The original arrival time t ₀ of the arrival time update part 1033 in the adjacent grid pk is greater than the arrival time min ₁ of the wavelet source (i, _{j) and the propagation time Δt k from} the wavelet source to the adjacent grid _pk When the sum value of , that is, min ₁ +Δt _k <t ₀ , the arrival time at the adjacent grid is updated to the sum value, that is, t ₁ =min ₁ +Δt _k .

The next-step wavelet source selection unit 1034 selects the grid with the smallest arrival time in the list of candidate grid groups as the next-step wavelet source.

The candidate grid group update unit 1035 deletes the grid that has been selected as the next wavelet source from the candidate grid group list.

If the number of the candidate grid group list is 1 or more, the candidate grid group adding unit 1032 , the arrival time updating unit 1033 , the next wavelet source selecting unit 1034 , and the candidate grid group updating unit 1035 repeat operations.

According to the tsunami prediction apparatus according to Example 1 of the second embodiment, the same technical effects as those of the tsunami prediction method according to Example 1 of the first embodiment can be obtained.

Example 2

Hereinafter, Embodiment 2 for realizing the arrival time calculation unit 103 will be described with reference to FIG. 9 .

In Embodiment 2, the next-step wavelet source selection unit 1034 in Embodiment 1 is replaced by the next-step wavelet source selection unit 1034 ′, and the minimum value calculation unit 1030 may also be included. Other structures are the same as those in Embodiment 1.

The minimum value calculation unit 1030 calculates the minimum value Δt _min of the propagation time between all adjacent grids, and outputs it to the next wavelet source selection unit 1034 ′.

In addition, the minimum value of the propagation time between all adjacent grids can also be calculated and stored by other modules, and the next wavelet source selection part 1034' directly uses the minimum value Δt _min . That is, the arrival time calculation unit 103 of the present invention may not include the minimum value calculation step 1030, and the minimum value calculation step 1030 may be omitted.

The next wavelet source selection unit 1034' selects multiple grids as the next wavelet source according to the minimum value Δt _min of the propagation time between all adjacent grids and the minimum value t _min of the arrival time in the grid group to be selected .

Specifically, the next wavelet source selection unit 1034' selects a grid whose arrival time is less than the sum of the minimum value Δt _min of the propagation time and the minimum value t _min of the arrival time in the grid group to be selected as the next step sub-wavelet. wave source. That is, for any grid pk ( _1≤k≤n , where n is the length of the list) in the grid group to be selected, if the arrival time at grid _pk Then this grid is selected as the next wavelet source.

In Embodiment 2, if the number of the grid group list to be selected is 1 or more, the grid group addition part 1032 to be selected, the arrival time update part 1033 , the next wavelet source selection part 1034 ′, the grid group to be selected The lattice group update unit 1035 repeats the operation.

According to the tsunami prediction apparatus according to Example 2 of the second embodiment, the same technical effects as those of the tsunami prediction method according to Example 2 of the first embodiment can be obtained.

<Third Embodiment>

The present invention can be realized by a tsunami early warning method.

As shown in FIG. 11 , the tsunami warning method according to the third embodiment includes an early warning step S105 in addition to the tsunami prediction method of the first embodiment.

In the early warning step 105 , according to the output result of the output step S104 of the tsunami prediction method, an early warning is issued for the area whose arrival time is less than a predetermined threshold.

For example, as shown in Fig. 10, contour lines can be drawn according to the size of the arrival time, and warning lines can be generated according to predetermined thresholds, and an early warning can be issued for the areas where the contour lines are located within the warning lines.

According to the third embodiment, an early warning can be issued in a timely manner to an area where the tsunami may reach, so that people in the disaster-affected area can respond to the disaster in time, thereby reducing casualties and economic losses.

<Fourth Embodiment>

The present invention can be realized by a tsunami warning device.

As shown in FIG. 12 , the tsunami warning device 2 according to the fourth embodiment includes an early warning unit 105 in addition to the tsunami prediction device 1 according to the second embodiment.

The early warning unit 105 issues a warning to a region whose arrival time is less than a predetermined threshold value based on the output result of the output unit 104 of the tsunami prediction apparatus.

For example, as shown in Fig. 10, contour lines can be drawn according to the size of the arrival time, and warning lines can be generated according to predetermined thresholds, and an early warning can be issued for the areas where the contour lines are located within the warning lines.

Also according to the fourth embodiment, the same effects as those of the third embodiment can be obtained.

Although the description has been made above with reference to the specific embodiments of the present invention, these embodiments are not intended to limit the present invention, but merely exemplify the present invention. Those skilled in the art will appreciate that various modifications, combinations and changes can be made to these specific embodiments, which should be regarded as being included in the present invention as long as they do not depart from the spirit and scope of the present invention as defined by the claims or their equivalents.

Claims (6)

1. a tsunami prediction method, is characterized in that, comprises: The data acquisition step is to acquire the spatial data of the tsunami propagation area; In the propagation time calculation step, according to the acquired data, the propagation time between adjacent grids is calculated and stored; In the calculation step of arrival time, the arrival time of each grid in the grid group to be selected is obtained according to the propagation time between the adjacent grids, and the arrival time of each grid in the grid group to be selected is obtained according to the difference of the arrival time of each grid in the grid group to be selected. minimum value, select the next wavelet source from the grid group to be selected, so as to calculate the arrival time of the tsunami to each grid in the tsunami propagation area, wherein the grid group to be selected may be used as a collection of grids of wavelet sources; and an output step, outputting the arrival time of each grid in the tsunami propagation area, The arrival time calculation steps include: In the initialization step, a two-dimensional array for storing the arrival times of all grids in the tsunami propagation area is set, and initialization is performed, and the arrival times of all grids except the epicenter are initialized to an infinite value, and the epicenter is selected as the initial wavelet source; The step of adding a grid group to be selected is to put the adjacent grids of the wavelet source into the grid group to be selected, and read in the propagation time from the wavelet source to the adjacent grid stored in the propagation time calculation step; Arrival time update step, when the arrival time of the adjacent grid is greater than the sum of the arrival time of the wavelet source and the propagation time from the wavelet source to the adjacent grid, the arrival time at the adjacent grid is updated to the specified value. the sum value; In the next step of selecting a wavelet source, the grid with the smallest arrival time is selected as the next wavelet source in the grid group to be selected; In the step of updating the grid group to be selected, the grid that has been selected as the next wavelet source is deleted from the grid group to be selected; When the number of grid groups to be selected is more than 1, the steps of adding grid groups to be selected, updating the arrival time, selecting the next wavelet source, and updating the grid groups to be selected are repeatedly performed. 2. The tsunami prediction method according to claim 1, wherein, The arrival time calculation step further includes: a minimum value calculation step, which calculates the minimum value of the propagation time between all adjacent grids; In the next step of selecting the wavelet source, instead of selecting the grid with the smallest arrival time in the candidate grid group as the next wavelet source, the grid is based on the minimum value of the propagation time between all adjacent grids. and the minimum arrival time in the grid group to be selected, select multiple grids as the next wavelet source. 3. A tsunami early warning method, characterized in that, comprising: The tsunami prediction method of claim 1 or 2; and In the early warning step, according to the output result of the tsunami prediction method, an early warning is issued for the area whose arrival time is less than a predetermined threshold. 4. A tsunami prediction device, characterized in that, comprising: The data acquisition department obtains the spatial data of the tsunami propagation area; The propagation time calculation part calculates and stores the propagation time between adjacent grids according to the acquired data; The arrival time calculation part obtains the arrival time of each grid in the grid group to be selected according to the propagation time between the adjacent grids, and obtains the arrival time of each grid in the grid group to be selected according to the difference of the arrival time of each grid in the grid group to be selected. minimum value, select the next wavelet source from the grid group to be selected, so as to calculate the arrival time of the tsunami to each grid in the tsunami propagation area, wherein the grid group to be selected may be used as a collection of grids of wavelet sources; and an output unit that outputs the arrival time of each grid in the tsunami propagation area, The arrival time calculation part includes: The initialization part sets a two-dimensional array for storing the arrival times of all grids in the tsunami propagation area, and performs initialization, initializes the arrival times of all grids except the epicenter to an infinite value, and selects the epicenter as the initial wavelet source; The grid group addition part to be selected puts the adjacent grids of the wavelet source into the grid group to be selected, and reads the propagation time from the wavelet source to the adjacent grids stored in the propagation time calculation part; The arrival time update part, when the arrival time of the adjacent grid is greater than the sum of the arrival time of the wavelet source and the propagation time from the wavelet source to the adjacent grid, the arrival time at the adjacent grid is updated to the specified value. the sum value; The next-step wavelet source selection part selects the grid with the smallest arrival time in the candidate grid group as the next-step wavelet source; The update part of the grid group to be selected deletes the grid that has been selected as the next wavelet source from the grid group to be selected; When the number of grid groups to be selected is 1 or more, the grid group addition part to be selected, the arrival time update part, the next wavelet source selection part, and the grid group update part to be selected are repeated. 5. The tsunami prediction apparatus according to claim 4, wherein: The arrival time calculation part also includes: The minimum value calculation part, which calculates the minimum value of the propagation time between all adjacent grids; The next-step wavelet source selection part does not select the grid with the smallest arrival time in the candidate grid group as the next-step wavelet source, but according to the minimum value of the propagation time between all adjacent grids and the candidate to be selected. The minimum arrival time in the grid group, and multiple grids are selected as the next wavelet source. 6. A tsunami warning device, comprising: The tsunami prediction device of claim 4 or 5; and The early warning unit issues an early warning to an area whose arrival time is less than a predetermined threshold value according to the output result of the tsunami prediction device.