JP5526541B2 - Debris flow risk judgment device, debris flow risk judgment method, and debris flow risk judgment program - Google Patents

Description

  The present invention relates to risk assessment of debris flow disasters, and more specifically, based on the rainfall judgment chart, the most recent rainfall at the current time, the maximum rainfall and the minimum rainfall before a predetermined time from the current time, and the risk of disaster occurrence and its accuracy. The present invention relates to a debris flow risk determination apparatus, a debris flow risk determination method, and a debris flow risk determination program.

  Regarding the risk of debris flow disasters due to heavy rain, the Ministry of Land, Infrastructure, Transport and Tourism and the prefecture have announced landslide disaster warning information in the landslide disaster information system, and based on this information, the city has decided to issue evacuation advisories, Judging voluntary evacuation. It is known to use, for example, a rain determination chart (also referred to as a sabo judgment chart) that represents, for example, two indicator rainfalls, hourly rainfall and effective rainfall, for the risk level prediction. In the rain judgment chart, a certain standard is set for each region based on the history of rainfall and sediment disaster that occurred in the past, and the degree of risk is predicted based on whether or not the future rainfall exceeds this standard.

  The rain amount determination diagram described above will be described in more detail. FIG. 7 shows an example of a rainfall judgment diagram, where the vertical axis is the hourly rainfall (unit: mm / h) which is the rainfall that has fallen in one hour, and the horizontal axis is the effective rainfall (unit: mm). Effective rainfall is the value obtained by adding continuous rainfall to the previous period's effective rainfall, but the previous period's effective rainfall is a coefficient that indicates how much rain remains in the ground in the rainfall that occurred before this series of rainfalls (referred to as the previous period's rainfall). Accumulated rainfall.

  CL (Critical Line) in the figure indicates a debris flow generation risk reference line, which is a risk level determined that the possibility of debris flow is most likely based on past results. The area above CL is dangerous for debris flow generation, and the area below is safe for the time being. The topography and geology differ from region to region, and CL is determined by the region.

  EL (Evacuation Line) represents the evacuation reference line, and is a guideline for people in this area to evacuate to safe places. The EL is calculated by taking the maximum amount of rainfall in the past in the area on the vertical axis, finding the point through which the line parallel to the horizontal axis intersects the CL, and dropping from that point perpendicular to the horizontal axis. Indicated by a straight line.

  WL (Warning Line) represents a warning reference line, which is an indication of evacuating to a safe place if you feel the danger and pay attention to the rainfall information. It is indicated by the effective rainfall one hour before arriving at the EL with the above maximum hourly rainfall.

  SL (Snake Line) represents a snake curve, and is a trajectory of rainfall represented by hourly rainfall and effective rainfall, which is a line obtained by plotting hourly rainfall and effective rainfall on a rainfall judgment diagram for each hour. If this SL exceeds CL, it means that there is a high possibility that a debris flow disaster will occur based on past debris flow disaster experiences. Although SL can be displayed using various types of rainfall information, here, hourly rainfall and effective rainfall are used as indices (see Non-Patent Document 1).

The forecaster in charge of disaster prevention predicts the occurrence of a debris flow disaster based on this rainfall judgment map. However, as described above, since there is no time display in the rain judgment chart, changes cannot be read in time series. For this reason, a technique for displaying the time on a rainfall determination diagram in order to support a forecaster's prediction determination is known (Patent Document 1).
Comprehensive debris flow countermeasures (II), warning guidelines for sediment-related disasters and precipitation setting guidelines for evacuation (draft), supervision of the Ministry of Construction River Bureau Sabo Department, Sabo Public Relations Center Planning Department Japanese Patent No. 3576911

  For prediction of debris flow disasters, forecasters input the future rainfall as a prediction line and draw it on the rainfall judgment map, and calculated the time to reach the reference line. For this reason, there was a problem that it took a lot of time to obtain the prediction result, and the response to the sediment disaster was delayed.

  In addition, as described above, the rainfall judgment map shows the past rainfall trajectory, and it is the forecaster's responsibility to read the rainfall trend from this rainfall judgment chart and to predict future rainfall based on past cases. It depends heavily on experience and intuition, and the forecast results may differ depending on the forecaster.

  Although it is thought that displaying the time on the rainfall judgment map proposed in Patent Document 1 will help to make the judgment of the forecaster more reliable, this is not enough, and it will increase the probability of further predicting the occurrence of a disaster. There is a need to increase it.

  An object of the present invention is to provide a debris flow risk judgment device, a debris flow risk judgment method, and a debris flow risk judgment program that can predict the occurrence of a debris flow disaster in a short time regardless of the skill of a forecaster.

  In order to achieve the above object, the debris flow risk determination apparatus includes an actual rainfall storage unit, a rainfall information acquisition unit, an effective rainfall calculation unit, a graph storage unit, a risk determination accuracy calculation unit, and an output unit.

Actual rainfall storage unit, and the previous fiscal year the effective rainfall based on the rainfall of the previous rainfall, and the rainfall per unit time,
The rainfall information including information on the time when the rainfall per unit time is measured is stored.

  The rainfall information acquisition unit acquires, from the actual rainfall storage unit, the most recent rainfall corresponding to the time closest to the current time, and the maximum and minimum rainfalls that indicate the maximum and minimum of the rainfall from the current time to a predetermined time ago. To do.

The effective rainfall calculation unit calculates the first nearest effective rainfall, which is the effective rainfall of the most recent rainfall, and the maximum effective rainfall, which is the respective effective rainfall when the maximum rainfall, the latest rainfall, and the minimum rainfall continue for a predetermined time from the current time. The second latest effective rainfall and the minimum effective rainfall are calculated with reference to the actual rainfall storage unit.
For required value before phase effective rainfall in the calculation of the effective rainfall, calculated with reference to the actual rainfall storage unit.

  The graph storage unit includes a first point based on the most recent rainfall and the first most recent effective rainfall, a second point based on the maximum and most effective rainfall, and the most recent rainfall and the second most recent effective rainfall. The positions of the third point based on the above and the fourth point based on the minimum rainfall and the minimum effective rainfall are calculated and stored on a graph with the vertical axis representing the hourly rainfall and the horizontal axis representing the effective rainfall.

  The risk determination accuracy calculation unit calculates a ratio of a region exceeding a predetermined value indicating a risk determination criterion defined in the graph to a polygonal region on the graph determined by the first to fourth points. Then, the accuracy of risk determination determined in advance corresponding to the ratio is obtained.

  The output unit includes a graph in which the first to fourth points stored in the graph storage unit and a line connecting the first to fourth points are plotted on the graph, and information relating to risk determination including accuracy. Is output.

  In the rainfall judgment chart, the most recent rainfall (current rainfall) at the current time, the maximum rainfall from the current time, the most recent rainfall, and the minimum rainfall for each predicted value of 4 when the rainfall continues for a predetermined time. Since the accuracy of risk determination is expressed by the ratio of the area that exceeds a predetermined reference value (for example, WL) with respect to the area determined by the point, the prediction result can be obtained in a short time without requiring manual input of the predicted value. Can be obtained. Moreover, the prediction result can know the accuracy of the determination together with the degree of danger. Also, since experience and intuition are eliminated, there is no variability due to the person in charge of forecasting.

  An embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 shows a configuration example of a debris flow risk judging device according to the present invention, and is a diagram showing only a portion related to the present invention. The debris flow hazard judgment device 100 includes a main control unit 110 that controls programs and data, a communication control unit 120 that receives rainfall data transmitted from a telemeter that observes rainfall, a keyboard (KB) 131, a display (DISP) 132, a speaker ( SP) I / O control unit 130 for controlling 133, debris flow risk determination program 150 developed on the main memory 140, actual rainfall storage unit 160 for storing rainfall data transmitted from the telemeter in association with measurement time, debris flow risk determination The program 150 includes a risk determination accuracy table 161 referred to for risk determination and a graph storage unit 162 that stores position information on the graph of the rainfall determination chart used for the determination.

  The debris flow risk determination program 150 further includes a rainfall information acquisition unit 151, an effective rainfall calculation unit 152, a graph position calculation unit 153, a risk determination accuracy calculation unit 154, and an output unit 155. Next, an outline of each part will be described.

  The rainfall information acquisition unit 151 acquires information on the latest rainfall and the maximum rainfall and the minimum rainfall from the current time to a predetermined time before the actual rainfall storage unit 160.

  The effective rainfall calculation unit 152 obtains the effective rainfall of the latest rainfall and the effective rainfall (which will be the predicted effective rainfall) when the maximum rainfall, the latest rainfall, and the minimum rainfall have continued for a predetermined time from the current time.

  Based on the rainfall acquired by the rainfall acquisition unit 151 and the effective rainfall calculated by the effective rainfall calculation unit 152, the graph position calculation unit 153 determines the position of the most recent rainfall on the graph (rainfall determination diagram) and the maximum rainfall for 3H. And the position of a total of four points of the position on a graph in the latest rainfall and the minimum rainfall is calculated | required.

  The risk determination accuracy calculation unit 154 calculates the ratio of the area exceeding the reference line representing the risk in the area determined by the position of the four points, and refers to the risk determination accuracy table 161 from the calculated ratio. Thus, the accuracy of risk determination is obtained, and display information of the accuracy is acquired.

  The output unit 155 displays the four points obtained by the graph position calculation unit 153, the area determined by the four points, and risk determination information on the display 132.

  Next, data examples of the actual rainfall storage unit 160 and the risk determination accuracy table 161 will be described.

  FIG. 2 shows an example of data in the actual rainfall storage unit 160. Based on the rainfall data transmitted from the telemeter, the debris flow hazard judgment device 100 records the rainfall data shown in the figure. The actual rainfall storage unit 160 measures “rainy date” and “time” at which the rainfall data is measured, “first-term effective rainfall” obtained by calculation from the rainfall before this series of rainfall, and “10-minute rainfall” observed by a telemeter. It consists of fields of “hourly rainfall” obtained by converting rainfall for 10 minutes into rainfall for one hour and “effective rainfall” determined by the effective rainfall in the previous period and the accumulated rainfall at that time.

  The data example in FIG. 2 shows an example in which a series of rainfalls started between 5:10 and 5:20 on December 1, 2008, from 5:00 on December 1, 2008 to the current time. The rainfall data for is shown.

  At 5:00, the effective rainfall for the previous period is 28 mm, calculated based on the rainfall for the previous period, and 0 mm for 10 minutes. The effective rainfall is a value obtained by adding the rainfall for 10 minutes to the effective rainfall for the previous period, and since the rainfall for 10 minutes is 0 mm, it is 28 mm which is the same as the effective rainfall for the previous period. At 5:20 when the first rainfall from the beginning of rainfall was obtained, the 10-minute rainfall was 0.5 mm, and the hourly rainfall was 3 mm, six times the rainfall for 10 minutes. The effective rainfall at this time is 28.5 mm, which is obtained by adding the rain of 0.5 mm for 10 minutes to the effective rainfall of 28 mm of 5:10. Note that the maximum rainfall and the minimum rainfall from the current time shown in FIG. 2 to 8 hours before are 16.8 mm and 1.8 mm, respectively.

  FIG. 3 shows an example of data in the risk determination accuracy table 161. Here, the warning level accuracy corresponding to the area ratio of the area to be described later at the warning level and an example of a display sentence displayed on the display 132 are shown. Yes. The area ratio obtained by calculation is rounded off to the nearest five. If it is 0, it is determined that the warning level has not been reached, 1% -10% is at the warning level with a probability of “small”, and 11% -30% is “ It is determined that there is a warning level with a probability of “medium” and 31% or more is at a warning level with a probability of “large”, and a display sentence corresponding to each probability is displayed on the display 132.

  Next, the processing flow of the debris flow risk determination apparatus 100 will be described. FIG. 4 shows a processing flow after the debris flow risk determination instruction is given by the operator and the debris flow risk determination program 150 is started. Here, it is assumed that the actual rainfall storage unit 160 and the risk determination accuracy table 161 store the data shown in FIGS. 2 and 3, respectively. In addition, the debris flow occurrence risk reference line (CL) is set as a primary line of Y = −33X + 80 in the rain judgment chart, and the evacuation reference line (EL) is at the position where the effective rainfall is 166 mm (the past maximum rainfall is 27 mm). Assume that the alert reference line (CL) is set at a position where the effective rainfall is 139 mm.

  First, the most recent rainfall amount and its effective rainfall amount, and the maximum and minimum rainfall amounts 8 hours before the current time (13:15) are obtained with reference to the actual rainfall storage unit 160. From FIG. 2, they are 12 mm, 108 mm (above, 13:30), 16.8 mm (10:00), and 1.8 mm (6:50) (S100).

  Next, the predicted maximum effective rainfall, the predicted latest effective rainfall, and the predicted minimum effective rainfall, which are the effective rainfalls when the maximum rainfall, the latest rainfall, and the minimum rainfall have continued for 3H from the current time, are obtained. The predicted maximum effective rainfall is 158.4 mm obtained by adding the maximum rainfall of 16.8 × 3 to 108 mm as the latest effective rainfall. Similarly, the predicted nearest effective rainfall and the predicted minimum effective rainfall can be 144 mm and 113.4 mm (S110).

  In the rainfall judgment chart, point A for the most recent rainfall and the latest effective rainfall, point B for the maximum rainfall and the predicted maximum effective rainfall, point C for the latest rainfall and the predicted latest effective rainfall, and point C for the minimum and predicted minimum effective rainfall Find D point. FIG. 5 shows the positions of the points A to D in the rainfall determination diagram. In addition, the dotted line parallel to the X-axis shown in FIG. 5 indicates the maximum rainfall, the latest rainfall, and the minimum rainfall from the upper side, and points B to D indicating the prediction after 3H are on the lines respectively. Become. The position of each point in the obtained rainfall judgment chart is stored in the graph storage unit 162 (S120).

  Subsequently, an area ratio between a region determined by A to D and a region where this region exceeds the warning reference line (WL) is obtained. The region exceeding the alert reference line is a region indicated by diagonal lines in FIG. 5 (S130).

  The risk ratio determination and its accuracy are obtained by referring to the risk determination accuracy table 161 for the obtained area ratio. For example, since the area ratio is 25% in this example, it can be seen that the warning level is at a medium accuracy with reference to the risk determination accuracy table 161. Information on the corresponding display text field is acquired (S140).

  The positions of the four points stored in the graph storage unit 162 are taken out, the four points and a polygon represented by sequentially connecting the four points, a line connecting the points B to D with the point A as the origin, Display information about the risk determination accuracy on the display. The display on the display is shown, for example, as shown in FIG. 6 (S150).

  When any of the lines connecting the points B to D with the point A as the origin exceeds the warning reference line, an alarm sound is notified from the speaker 133 to alert the operator. As shown in FIG. 6, the predicted maximum rainfall (point B) and predicted most recent rainfall (point C) after 3H connected from the position of the latest rainfall (namely, the position of point A) with respect to the current time. Since the line exceeds the warning reference line, an alarm sound is notified. In this example, the alarm sound is notified. However, since the purpose is to alert the operator, the display of the risk determination information may be blinked instead of the alarm sound, for example. Such a method may be used (S160).

  1 in each step in the processing flow of FIG. 4 is the rainfall information acquisition unit 151 in step 100 (hereinafter referred to as S100), the effective rainfall calculation unit 152 in S110, the graph position calculation unit 153 in S120, and S130. And S140 are the risk determination accuracy calculation unit 154, and S150 and S160 are the output unit 155.

  In the present embodiment, the risk level and the accuracy are determined for the warning reference line (WL), but there may be an evacuation reference line (EL) or a debris flow generation risk reference line (CL). You may do it at the same time. When performing at the same time, since the risk level is CL> EL> WL, the risk determination and its accuracy may be displayed in the order of high risk.

  In the present embodiment, the risk and the accuracy are automatically expressed based on the predicted rainfall after 3H. However, the operator may input an arbitrary predicted time.

  Further, the present invention may be automatically executed at predetermined time intervals.

It is an example of composition of a debris flow danger judging device. It is an example of the data of an actual rainfall storage part. It is an example of data setting of a risk determination accuracy table. It is an example of a processing flow of risk determination. It is explanatory drawing for calculating the accuracy of risk determination. It is an example of a display on a display. It is an example of the example of a rainfall determination figure.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Debris flow danger determination apparatus 110 Main control part 120 Communication control part 130 Input / output control part 131 Keyboard (KB)
132 Display (DISP)
133 Speaker (SP)
140 Main Memory 150 Debris Flow Risk Determination Program 151 Rainfall Information Acquisition Unit 152 Effective Rainfall Calculation Unit 153 Graph Position Calculation Unit 154 Risk Determination Accuracy Calculation Unit 155 Output Unit 160 Actual Rainfall Storage Unit 162 Risk Level Determination Accuracy Table 163 Graph Storage Unit

Claims (6)

A previous period effective rainfall based on rainfall before rainfall, the rainfall per unit time, and actual rainfall storage unit for storing the rainfall information including information on the time measured rainfall per the unit time,
Rainfall information for acquiring the latest rainfall corresponding to the time nearest to the current time and the maximum and minimum rainfalls indicating the maximum and minimum of the rainfall from the current time to a predetermined time before from the actual rainfall storage unit. An acquisition unit;
A first nearest effective rainfall that is an effective rainfall of the latest rainfall, a maximum effective rainfall that is an effective rainfall when the maximum rainfall, the latest rainfall, and the minimum rainfall have continued for a predetermined time from a current time; An effective rainfall calculation unit for calculating the latest effective rainfall and the minimum effective rainfall with reference to the actual rainfall storage unit,
A first point based on the most recent rainfall and the first nearest effective rainfall; a second point based on the maximum rainfall and the maximum effective rainfall; and the most recent rainfall and the second most recent effective rainfall. The position of the third point based on the above and the fourth point based on the minimum rainfall and the minimum effective rainfall are calculated and stored on a graph with the vertical axis representing the hourly rainfall and the horizontal axis representing the effective rainfall. A graph storage unit to
For the polygonal area on the graph determined by the first to fourth points, calculate the ratio of the area exceeding the predetermined value indicating the criterion of risk determination defined in the graph, and correspond to the ratio A risk determination accuracy calculation unit for obtaining a predetermined risk determination accuracy;
Information regarding risk determination including the accuracy and a graph in which the first to fourth points stored in the graph storage unit and a line connecting the first to fourth points are plotted on the graph. And a debris flow hazard judgment device characterized by comprising: an output unit for outputting. The output unit further includes a line connecting the first point and the second point, the first point and the third point, and the first point and the fourth point stored in the graph storage unit. The debris flow risk determination device according to claim 1, wherein an alarm is output when any of the values exceeds a predetermined value on the graph. A previous period effective rainfall based on rainfall before rainfall, the rainfall per unit time, from actual rainfall storage unit that stores rainfall information including information on the time measured rainfall per the unit time, the most recent to current time Rainfall information acquisition procedure for acquiring the latest rainfall corresponding to the time, the maximum rainfall showing the maximum and the minimum rainfall showing the minimum of the rainfall from the current time to a predetermined time before,
A first nearest effective rainfall that is an effective rainfall of the latest rainfall, a maximum effective rainfall that is an effective rainfall when the maximum rainfall, the latest rainfall, and the minimum rainfall have continued for a predetermined time from a current time; An effective rainfall calculation procedure for calculating the latest effective rainfall and the minimum effective rainfall with reference to the actual rainfall storage unit,
A first point based on the most recent rainfall and the first nearest effective rainfall; a second point based on the maximum rainfall and the maximum effective rainfall; and the most recent rainfall and the second most recent effective rainfall. The position of the third point based on the above and the fourth point based on the minimum rainfall and the minimum effective rainfall are calculated on a graph with the vertical axis representing the hourly rainfall and the horizontal axis representing the effective rainfall. A graph storage procedure to be stored in the storage unit;
For the polygonal area on the graph determined by the first to fourth points, calculate the ratio of the area exceeding the predetermined value indicating the criterion of risk determination defined in the graph, and correspond to the ratio A risk determination accuracy calculation procedure for obtaining a predetermined risk determination accuracy;
Information regarding risk determination including the accuracy and a graph in which the first to fourth points stored in the graph storage unit and a line connecting the first to fourth points are plotted on the graph. And a debris flow hazard judgment method characterized by comprising: The output procedure further includes a line connecting the first point and the second point, the first point and the third point, and the first point and the fourth point stored in the graph storage unit. The debris flow risk determination method according to claim 3, wherein an alarm is output when any one of the graphs exceeds a predetermined value on the graph. On the computer,
A previous period effective rainfall based on rainfall before rainfall, the rainfall per unit time, from actual rainfall storage unit that stores rainfall information including information on the time measured rainfall per the unit time, the most recent to current time Rainfall information acquisition procedure for acquiring the latest rainfall corresponding to the time, the maximum rainfall showing the maximum and the minimum rainfall showing the minimum of the rainfall from the current time to a predetermined time before,
A first nearest effective rainfall that is an effective rainfall of the latest rainfall, a maximum effective rainfall that is an effective rainfall when the maximum rainfall, the latest rainfall, and the minimum rainfall have continued for a predetermined time from a current time; An effective rainfall calculation procedure for calculating the latest effective rainfall and the minimum effective rainfall with reference to the actual rainfall storage unit,
A first point based on the most recent rainfall and the first nearest effective rainfall; a second point based on the maximum rainfall and the maximum effective rainfall; and the most recent rainfall and the second most recent effective rainfall. The position of the third point based on the above and the fourth point based on the minimum rainfall and the minimum effective rainfall are calculated on a graph with the vertical axis representing the hourly rainfall and the horizontal axis representing the effective rainfall. A graph storage procedure to be stored in the storage unit;
For the polygonal area on the graph determined by the first to fourth points, calculate the ratio of the area exceeding the predetermined value indicating the criterion of risk determination defined in the graph, and correspond to the ratio A risk determination accuracy calculation procedure for obtaining a predetermined risk determination accuracy;
Information regarding risk determination including the accuracy and a graph in which the first to fourth points stored in the graph storage unit and a line connecting the first to fourth points are plotted on the graph. A debris flow risk assessment program for executing the output procedure. The output procedure further includes a line connecting the first point and the second point, the first point and the third point, and the first point and the fourth point stored in the graph storage unit. The debris flow risk judgment program according to claim 5, wherein any one of them outputs an alarm when a predetermined value on the graph is exceeded.

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