Disaster risk assessment system

Abstract

To accurately assess disaster risk at specific locations within a particular region after several years have passed. [Solution] The disaster risk assessment system 1 assesses the disaster risk at a specific location within a particular area after several years have passed. It comprises a disaster risk calculation unit 11 that calculates the disaster risk, which is an index indicating the extent of human casualties that may be incurred by a disaster at the location after several years have passed, based on the disaster frequency, which indicates the frequency with which a disaster will occur at the location up to several years in the future, the estimated population at the time several years have passed, and vulnerability, which is a coefficient indicating how vulnerable people exposed to the disaster are to the disaster and how great the extent of damage to those people may be. It also includes a disaster risk display unit 12 that displays the disaster risk for the location.

Description

[Technical Field]

[0001] This invention relates to a disaster risk assessment system that evaluates the disaster risk at a specific location within a particular area after a period of time. [Background technology]

[0002] Assessments are being made to evaluate the risks associated with future disasters. For example, Patent Document 1 discloses an earthquake risk assessment method for evaluating the earthquake risk of a building having multiple floors using PML. This earthquake risk assessment method calculates the loss distribution of a building with respect to the magnitude of seismic motion, which forms the basis of PML, based on the correlation coefficient between the magnitude of seismic motion and the response value between each floor and part of the building, and the correlation coefficient between the load-bearing capacity values ​​between each floor and part of the building, as well as the loss distribution in each floor and part of the building.

[0003] In Patent Document 1, the subject of evaluation is a building. Therefore, the system and method disclosed in Patent Document 1 would be used, for example, by the building owner. In contrast, from the perspective of local administration and disaster prevention, for example, it is conceivable to evaluate the disaster risk of specific locations within a designated area of ​​a certain size, with the aim of identifying locations that would suffer significant damage in the event of a disaster.

[0004] In this regard, Patent Document 2 discloses a risk assessment method for evaluating the risk of human casualties caused by a disaster for each of several sections obtained by dividing a predetermined area. This risk assessment method includes calculating the vulnerability to human casualties for each of the several sections at each future time based on dynamic regional information indicating the state of the section as it changes at each future time, and evaluating the risk for each of the several sections at each future time based on the calculated vulnerability of the section. Patent Document 2 discloses that each of the above future time points is, for example, several hours to several days from the present, within a range where human casualties due to a disaster are likely to occur. Furthermore, Patent Document 3 discloses an evacuation decision support method that includes evaluating the risk of human casualties due to a disaster for each of several sections obtained by dividing a predetermined area, at each future time, evaluating the evacuation stage for each evacuation unit, which is composed of some sections of the multiple sections established within the predetermined area, based on the risk of each of the sections, and outputting the evaluated evacuation stage. In Patent Document 3, as in Patent Document 2, it is disclosed that the above future time is, for example, a few hours to a few days from the present, to the extent that human casualties due to a disaster are likely to occur.

[0005] Incidentally, from the perspective of administration and disaster prevention in the aforementioned regions, there is an idea to evaluate the disaster risk within a specific area as a possible extent of damage from a disaster several decades from now, and to utilize the results in future urban development. If disaster risk is to be applied to such medium- to long-term disaster prevention urban development plans, it is necessary to evaluate the disaster risk in the future, at least several years from now. In contrast, as mentioned above, Patent Documents 2 and 3 aim to efficiently carry out initial responses when a disaster occurs by evaluating the risk in the period of several hours to several days after a disaster occurs. For this reason, the risk evaluated by the configuration of Patent Documents 2 and 3 may be difficult to use in medium- to long-term disaster prevention urban development plans, as it deviates from the disaster risk in the future, several years from now. There is a need to accurately assess the disaster risk at specific locations within a particular region after several years have passed. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2011-27481 [Patent Document 2] Japanese Patent Publication No. 2022-81072 [Patent Document 3] Japanese Patent Publication No. 2022-81074 [Overview of the project] [Problems that the invention aims to solve]

[0007] The problem that this invention aims to solve is to provide a disaster risk assessment system that can accurately evaluate the disaster risk at a specific location within a particular area after several years have passed. [Means for solving the problem]

[0008] To solve the above problems, the present invention employs the following means. That is, the present invention provides a disaster risk assessment system for evaluating the disaster risk at a point in a specific area after several years have passed, comprising: a disaster risk calculation unit that calculates the disaster risk, which is an index indicating the degree of human casualties that may be suffered by the disaster at the point after several years have passed, based on: a disaster frequency indicating the frequency with which the disaster will occur at the point up to the passage of several years; an estimated population at the time after several years have passed; and a vulnerability coefficient indicating the degree to which a person exposed to the disaster is vulnerable to the disaster and how great the extent of damage to that person may be; and a disaster risk display unit that displays the disaster risk for the point. When evaluating disaster risk, which is an indicator of the extent of human casualties that may occur due to a disaster at a specific location within a particular region several years later, the population of the location being evaluated is required as input for processing. However, when evaluating disaster risk at a location several years later, the population of that location may change over those years. Therefore, evaluating disaster risk several years later based on the current population of the location being evaluated may not yield sufficient accuracy. In contrast, with the configuration described above, the disaster risk calculation unit calculates disaster risk, an index indicating the extent of human casualties that may be incurred by a disaster at the location several years later, based on the following: disaster frequency, which indicates the frequency of disasters occurring at the location up to several years later; the estimated population at the time several years later; and vulnerability, which is a coefficient indicating how vulnerable people exposed to a disaster are to the disaster and how significant the extent of their damage may be. Thus, the disaster risk calculation unit calculates disaster risk based on the estimated population several years later, not the current population. The disaster risk calculated in this way takes into account the population of the location several years later, not the current population, and therefore has higher accuracy compared to evaluating disaster risk based on the current population. Furthermore, the disaster risk calculation unit evaluates disaster risk based on estimated population figures several years into the future, as well as, as described above, the frequency of disaster occurrence and vulnerability. Therefore, the calculated disaster risk reflects the frequency of future disaster occurrences, the degree of vulnerability of individuals exposed to such disasters, and the potential extent of their damage. Because both the frequency of disaster occurrence and the susceptibility of individuals to harm are reflected in this calculation, the accuracy of the disaster risk is further enhanced. In this way, it becomes possible to accurately assess the disaster risk at specific locations within a particular area when a disaster occurs several years later.

[0009] In one aspect of the present invention, the estimated population and vulnerability are set for each age group, the disaster risk calculation unit uses the vulnerability as a weighting coefficient for each age group, calculates a value obtained by multiplying the estimated population and vulnerability for each age group, calculates the sum of these values, and calculates the disaster risk based on the disaster frequency, the indicator for the intensity of the disaster, and the sum. In the event of a disaster, it is thought that older people, for example, are more likely to suffer greater human casualties than younger people when exposed to the disaster. In contrast, with the configuration described above, the estimated population and vulnerability are set for each age group, and the disaster risk calculation unit uses vulnerability as a weighting coefficient for each age group, calculates a value by multiplying the estimated population and vulnerability for each age group, and then calculates the sum of these values. The sum calculated in this way reflects the susceptibility and magnitude of damage for each age group, which have been adjusted for each age group by vulnerability. By calculating the disaster risk based on the sum calculated in this way, it becomes possible to evaluate the disaster risk with greater accuracy. Furthermore, while the sum calculated as described above indicates the extent of human casualties in the event of a disaster, in the configuration described above, disaster risk is calculated based on this sum, along with indicators related to the frequency and intensity of disasters. In this way, since the frequency and intensity of disasters are reflected in the calculation of disaster risk, the disaster risk assessment system is further improved.

[0010] In another embodiment of the present invention, the vulnerability is calculated for each era by obtaining the number of victims in each of several past disaster cases in each era, dividing the number of victims in each of the several disaster cases by the population of that era at the location where the disaster occurred, and calculating the median of the division values ​​among the several disaster cases in each era, and calculating the multiplier of the median of one era to the median of another era. With the above configuration, the number of victims for each age group is obtained for multiple past disaster cases. Since each of the multiple disaster cases obtained in this way may have occurred in different regions or time periods, the composition of the population affected by the disasters may also differ. In response to this, as described above, the number of victims for each age group in each of the multiple disaster cases is divided by the population of that age group at the location where the disaster occurred, thereby standardizing the number of victims for each age group in each of the multiple disaster cases. In this way, a value is calculated as the division value that excludes the influence of the population composition due to the region and time period in which the disaster occurred. Then, for each age group, the median of the division values ​​calculated as described above is calculated among the multiple disaster cases, and by calculating the multiplier of the median of one age group to the median of another age group, a representative value of the multiplier of the number of victims for each age group, which excludes the influence of the population composition due to the region and time period in which the disaster occurred, can be appropriately determined. By using the multiplier obtained in this way as the vulnerability for each age group, it becomes possible to evaluate disaster risk with greater accuracy. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a disaster risk assessment system that can accurately evaluate the disaster risk at a specific location within a particular area after several years have elapsed. [Brief explanation of the drawing]

[0012] [Figure 1] This is a block diagram of a disaster risk assessment system according to an embodiment of the present invention. [Figure 2] This figure shows the estimated population for each location within a specific region in 2020, based on the 2015 census. [Figure 3] This figure shows the estimated population for each location within a specific region in 2050, based on the 2015 census. [Figure 4]This figure shows the percentage of the population in their 70s at each location within a specific region in 2020, based on the 2015 census. [Figure 5] This figure shows the projected population ratio of people in their 70s at each location within a specific region in 2050, based on the 2015 census. [Figure 6] This figure shows an example of vulnerability, a coefficient used in the above-mentioned disaster risk assessment system, when the disaster is defined as an earthquake. [Figure 7] This figure shows the number of deaths by age group in each of several earthquakes that have occurred in the past. [Figure 8] This figure shows the age-specific mortality rate, which is calculated by dividing the number of deaths shown in Figure 7 by the population of the affected area in that age group during a period close to the year the disaster occurred. [Figure 9] Figure 8 shows the results of statistical analysis by age group. [Figure 10] This figure shows an example of vulnerability, a coefficient used in the above-mentioned disaster risk assessment system, when the disaster is defined as wind and flood damage. [Figure 11] This figure shows the number of deaths by age group in each of several past wind and flood disasters. [Figure 12] This figure shows the age-specific mortality rate, which is calculated by dividing the number of deaths shown in Figure 11 by the population of the affected area in that age group during a period close to the year the disaster occurred. [Figure 13] Figure 12 shows the results of statistical analysis by age group. [Figure 14] This figure shows the disaster risk calculated for each location within a specific region, based on the year 2020. [Figure 15] This figure shows the disaster risk calculated for each location within a specific region, targeting the year 2050. [Modes for carrying out the invention]

[0013] This invention is a disaster risk assessment system that evaluates the risk of disasters such as earthquakes, floods, tsunamis, and volcanic eruptions at specific locations within a particular region after several years have passed. This system evaluates the disaster risk of a particular location not based on the present, but on the estimated population of that location several years from the present, using an indicator that comprehensively shows the likelihood (probability, frequency) of a disaster occurring and the impact of the disaster's intensity on human casualties. Embodiments of the present invention will be described in detail below with reference to the drawings. Figure 1 is a block diagram of the disaster risk assessment system in this embodiment. The disaster risk assessment system 1 of this embodiment assesses the disaster risk at a specific location within a designated area. In particular, the disaster risk assessment system 1 of this embodiment assesses the disaster risk at a specific location within a designated area in the future relative to the present time, with the present time being used as the time for assessing the disaster risk. Here, "future" does not refer to the short term, such as a few hours to a few days from the present, when initial response measures are taken after a disaster occurs, but rather to the medium to long term, such as a decade or several decades from the present time, or at least several years. Thus, the disaster risk assessment system 1 of this embodiment assesses the disaster risk at a specific location within a designated area in the future, several years after the present time. In this embodiment, disaster risk is an index that comprehensively shows the probability and frequency of a disaster occurring, as well as the impact of the intensity of the disaster on human casualties, including the likelihood of a disaster occurring in the future and, if a disaster occurs, the potential extent of human casualties. Disaster risk assessment system 1 operates on an information processing terminal such as a personal computer or server. Disaster risk assessment system 1 functionally includes a disaster risk calculation unit 11, a disaster risk display unit 12, and a database 13.

[0014] Disasters that are subject to disaster risk assessment in Disaster Risk Assessment System 1 include, for example, earthquakes, floods, tsunamis, and volcanic eruptions. In this embodiment, Disaster Risk Assessment System 1 specifically targets earthquakes as the target disaster. Therefore, the following explanation will primarily focus on cases where the disaster is an earthquake, but explanations for other disasters such as tsunamis and floods will also be included as needed.

[0015] Figure 2 shows the estimated population at each location within a specific region in 2020, based on the 2015 census. Figure 3 shows the estimated population at each location within a specific region in 2050, based on the 2015 census. Disaster Risk Assessment System 1 assesses the disaster risk within a specific area R after a period of several years. The specific area R to be assessed in Disaster Risk Assessment System 1 may be a limited area, for example, one that forms a rectangular shape when viewed from above, as shown in Figure 2, by specifying a range of latitude and longitude. Alternatively, the specific area R may be an administrative division such as a specific prefecture, city, or town. In this embodiment, the disaster risk assessment system 1 evaluates the disaster risk for each of the multiple locations L included in a specific region R. In this embodiment, the specific region R is subdivided into a mesh by dividing it into predetermined intervals of latitude and longitude in the east-west direction, with each mesh corresponding to one location L. Therefore, the disaster risk assessment system 1 of this embodiment evaluates the disaster risk for each of the locations L shown as meshes in Figure 2. For example, GIS (Geographic Information System) data can be used as this type of data. Alternatively, in disaster risk assessment system 1, each of the multiple points L included in a specific area R may be an administrative division such as a specific city or town.

[0016] The disaster risk calculation unit 11 calculates disaster risk, an index indicating the extent of human casualties that may be incurred by a disaster at location L after several years have passed, based on the disaster frequency, which indicates the frequency of disasters occurring at location L up to several years in the future; the estimated population at the time several years have passed; and vulnerability, which is a coefficient indicating how vulnerable people exposed to a disaster are to that disaster and how great the extent of their damage may be. Here, we will first explain the disaster frequency, which indicates the frequency of disasters occurring at location L up to several years in the future. Hereafter, in cases where a certain value differs for each location L, or when it is necessary to distinguish and explain multiple locations L from one another, the i-th location L (i=1 to M) within a specific region R may be referred to as location i, etc., where M is the total number of locations L (meshes).

[0017] In this embodiment, the disaster occurrence frequency H indicates the frequency at which a disaster will occur in the future up to several years from now at point i. i At point i, the intensity of the disaster is expected to be S in the next T years. i However, the probability value Prob that exceeds the threshold S of the intensity of a disaster that could result in human casualties is expressed as equation (1) below.

number

[0018] Also, in this embodiment, the disaster occurrence frequency H i (S i >S;T) is set for each of a plurality of elapsed years T. For example, the plurality of elapsed years T can be set to 10 years, 50 years, 90 years, etc. In this case, for each of a plurality of points i within a specific region R, the disaster occurrence frequency H i (S i >S;T) can be set as the frequency of a disaster occurring at the point i until 10 years have elapsed from the current time (present), the frequency of a disaster occurring at the point i until 50 years have elapsed from the current time, and the frequency of a disaster occurring at the point i until 90 years have elapsed from the current time. The plurality of elapsed years T can be set to different values other than the above. Alternatively, the disaster occurrence frequency H i (S i >S;T) can be set as a function whose value changes continuously as the elapsed year T increases.

[0019] Such a disaster occurrence frequency H indicating the frequency of a disaster occurring at the point i in the future until several years have elapsed i (S i >S;T) is stored in the database 13. The disaster occurrence frequency H i (S i>S;T) is stored in database 13 for each of the multiple locations i, and for each of the multiple elapsed years T, as the frequency with which a disaster occurs at location i from the present time until the elapsed years T have passed, corresponding to each of the multiple elapsed years T.

[0020] Next, we will explain the estimated population of location i after several years have passed. In this embodiment, the disaster risk assessment system 1 calculates the disaster risk at each point i by considering how many people will be affected at that point i, based on the population at that point i. As already explained, in this embodiment, the disaster risk is calculated for at least several years from the present. In such a future, at least several years from the present, the population at point i is likely to have increased or decreased compared to the present, causing fluctuations. Therefore, if the disaster risk is assessed based on the population at the present time, the assessed disaster risk value may not be accurate in reflecting the future situation. Therefore, in this embodiment, disaster risk is assessed based on the estimated population at a point in time at least several years after the present, which is the point at which the disaster risk is to be evaluated. For example, as the estimated population of point i, we can use the population of point i based on a future census, for example, T years from the present, as shown in Figures 2 and 3.

[0021] In this embodiment, the estimated population is set for each age group. Figure 4 shows the population ratio of people in their 70s at each location within a specific region in 2020, based on the 2015 census. Figure 5 shows the population ratio of people in their 70s at each location within a specific region in 2050, based on the 2015 census. For example, divide age into P age-specific categories, and each category is a j Let (j=1~P), and determine the age a at point i after T years have passed from the present time. jThe estimated population of P i、aj Let (T) be the estimated population P of point i at a time T years after the present. i (T) can be expressed as shown in equation (2) below.

number

[0022] The estimated population P as described above i Based on (T), the frequency of disaster occurrence H at point i after T years have passed from the present time. i (S i >S;T) indicates intensity S i Exposed population E is an indicator that shows the extent to which the population is exposed to and affected by a disaster in which the threshold S exceeds. i (H i It is possible to calculate T). In this embodiment, exposure crew E i (H i , T) are calculated by the following equation (3).

number

number

[0023] As in this embodiment, when the target disaster is an earthquake, the influence function f(S) is calculated based on, for example, the surface ground amplification factor of J-SHIS (earthquake hazard station) for each point i, the microtopographic classification, whether point i is a large-scale construction site or not, whether point i is a landslide hazard zone or not, etc. i ) may be set. If the disaster is, for example, a tsunami, the influence function f(S i ) can be set, for example, based on the tsunami inundation depth set for each of point i. The function f(Si) required to calculate the exposed population Ei(Hi, T) is stored in database 13.

[0024] Next, I will explain vulnerability. Vulnerability is a coefficient that indicates how vulnerable a person exposed to a disaster is to that disaster and how great the extent of their damage may be. i (H iT) is the extent to which the population is exposed to and affected by a disaster when it occurs. By multiplying this by vulnerability, which is a coefficient that indicates how great the extent of the damage to those exposed to the disaster may be, as explained below, the exposed population E is obtained. i (H i This allows us to understand the actual extent of the damage caused by (T).

[0025] Figure 6 shows an example of vulnerability, a coefficient used in the disaster risk assessment system described above, when the disaster is defined as an earthquake. In Figure 6, the vulnerability value for those in their 50s is set to 1, and the vulnerability values ​​for other age groups are standardized. When a disaster occurs, the degree of vulnerability—how severe the damage to those exposed to the disaster may be—is thought to differ depending on age. For example, as shown in Figure 6, if the vulnerability value for those in their 50s is set to 1, the vulnerability value for those in their 70s is 3.5, and the vulnerability value for those in their 80s is 5.7, both of which are greater than 1. Thus, when an earthquake occurs, the risk of death tends to increase with age. In this embodiment, vulnerability is set for each age group, and this is used as a weight to evaluate disaster risk, thereby reflecting the above-mentioned trend in the evaluation of disaster risk. With this configuration, it becomes possible to clearly reflect regional vulnerability that depends on the age structure, such as the aging of the region, in the evaluation of disaster risk.

[0026] The vulnerability value, as shown in Figure 6, can be derived, for example, as follows: Figure 7 shows the number of deaths by age group in each of several earthquakes that have occurred in the past. First, we obtain data on the number of victims by year for several past disasters. Specifically, we obtain the number of victims for each year for several past earthquakes. Here, the number of fatalities is used as the number of victims. In Figure 7, the number of fatalities for six disasters is plotted and shown.

[0027] However, since each of the multiple disaster cases occurred in a different time period and region, the composition of the affected population differs. To eliminate the influence of these differences in population composition, the number of victims in each of the multiple disaster cases is corrected using population data (such as census or resident registration data) from the location where the disaster occurred, i.e., the affected area. If population data for the affected area at the time of the disaster is not available, population data for the affected area from a period close to the time of the disaster is used. Specifically, for each of several past disaster cases, the number of victims in each decade is divided by the population of that decade at the location where the disaster occurred, to calculate the division value. Figure 8 shows the age-specific mortality rate, which is calculated by dividing the number of deaths shown in Figure 7 by the population of the affected area in that age group during a period close to the year the disaster occurred. The above division values ​​correspond to the age-specific mortality rates in Figure 8. Through the operations described above, the influence of differences in population composition is eliminated, and the division value shown in Figure 8 is generated.

[0028] Figure 9 shows the results of statistical analysis of Figure 8 by age group. Next, for each time period, the median of the corrected division values ​​is calculated among the multiple disaster cases as described above. In Figure 9, the median is calculated by generating box plots for each time period for the division values ​​shown in Figure 8. Then, with respect to the median of the division value calculated for each age group as shown in Figure 9, a ratio of the medians of the other age groups to the median of one age group selected from among the multiple age groups is calculated. Here, as already explained, this one age group is set to the 50s, and each of the medians of the other age groups is divided by the median of the 50s to normalize the median of the 50s to 1, and the ratios of the other age groups are calculated. In this embodiment, the ratios calculated in this way are used as vulnerability values, as shown in Figure 6.

[0029] Figure 10 shows an example of vulnerability, a coefficient used in the disaster risk assessment system described above, when the disaster is defined as wind and flood damage. Even if the disaster being assessed for disaster risk is, for example, a wind and flood, a vulnerability value can be calculated as shown in Figure 10. Figure 11 shows the number of deaths by age group for each of several past wind and flood disasters. Figure 12 shows the age-specific death rate, which is calculated by dividing the number of deaths shown in Figure 11 by the population of the affected area in that age group during a period close to the year the disaster occurred. Figure 13 shows the results of statistical analysis of Figure 12 by age group. Figures 11, 12, and 13 correspond to Figures 7, 8, and 9, respectively, which were used to explain the case where the disaster in question is an earthquake. Thus, even when dealing with disasters other than earthquakes, the vulnerability value is calculated based on victim data obtained from past disaster cases related to the disaster in question.

[0030] As described above, the vulnerability value is determined based on victim data obtained from past disaster cases, according to the type of disaster (earthquake, wind and flood damage, etc.) being assessed for disaster risk. In other words, in this embodiment, the vulnerability value is determined according to the type of disaster. From the perspective of more accurately assessing disaster risk, it is desirable that the vulnerability value be set to depend not only on the type of disaster being assessed, but also on other factors such as the location, characteristics, and nature of the specific region R and point i being assessed, as well as the timing of the disaster incident. To achieve this, for example, it would be necessary to calculate the vulnerability by limiting the calculation to only disasters that occurred in the specific region R. However, limiting the region and time period results in a very small number of past disaster incidents, making it difficult to set a valid vulnerability value by performing the above processing. Therefore, in this embodiment, the vulnerability value is calculated as a statistical multiplier by applying the population by age at the region and time of the disaster, as described above, to victim data from multiple disaster cases obtained regardless of region or time. This configuration ensures that the vulnerability value is not limited to a specific region or time, but is a value that can be applied to other regions and times.

[0031] Thus, the vulnerability value can be set as a value independent of location i or time (number of years elapsed from the present). Therefore, in this embodiment, the vulnerability (coefficient) V(H) due to disaster H is a constant value c determined by the time period, as follows. H (a j It can be expressed as:

number

[0032] In the above explanation, the number of deaths by age group was used to calculate the vulnerability value, but this is not the only method. The vulnerability value may also be calculated based on the number of injured people by age group (number of minor injuries, number of serious injuries, or the sum of minor and serious injuries). Furthermore, vulnerability values ​​may be categorized and set differently depending on gender, in addition to age. Furthermore, in the above explanation, when calculating the vulnerability value, one age group selected from multiple age groups was designated as the 50s, and the median values ​​of each of the other age groups were standardized by dividing each of the median values ​​of the 50s by the median value of the 50s, so that the median value of the 50s becomes 1, and the multipliers for the other age groups were calculated. However, this is not the only way. It goes without saying that any other age group can be designated as the first age group. The vulnerability V(H) (i.e., the constant value c) calculated in this way H (a j )) is stored in database 13.

[0033] The disaster risk calculation unit 11 calculates the disaster frequency H, which indicates the frequency with which a disaster will occur at point i in the future over a period of several years T, as calculated above.i (S i >S;T), estimated population P of point i after several years T have passed. i (T), Influence function f(S i ), vulnerability V(H) (i.e., constant value c) H (a j )) Retrieve each of these from database 13. Based on these, the disaster risk calculation unit 11 calculates the disaster risk R of location i in the future after several years T have passed. i (H i ;T) is calculated using the following equation (6).

number

[0034] In the above equation, the frequency of disaster occurrence H i (S i >S;T) and the exposed population E i (H i , T) (i.e., estimated population P i (T) and the influence function f(S) i (The result of multiplying by ) and vulnerability V(H) (i.e., the constant value c) H (a j )) and are configured to be multiplied together. As already explained, the exposed population E i (H i ,T) is the intensity S at point i after T years have passed from the present time. i This is an index that shows the extent to which the population is exposed to and affected by a disaster that exceeds the threshold S. Therefore, the exposed population E i (H i By multiplying the vulnerability V(H) by T, the strength S i The extent of human casualties is calculated in the event of a disaster that exceeds the threshold S. In addition, the frequency (probability) of the disaster occurring, H, is calculated. i (S i By multiplying by (S;T), we can calculate the disaster risk, which is an indicator of the extent of human damage that could be caused by a disaster at point i T years from the present.

[0035] Also, the disaster occurrence frequency H i (S i >S;T) is the frequency (probability) of a disaster occurring. Considering that the influence function f(S i ) is an index related to the intensity of the disaster, it is considered that when these disaster occurrence frequencies H i (S i >S;T) and the influence function f(S i ) are multiplied, the risk of the disaster, which takes into account both the frequency and intensity of the disaster, is comprehensively expressed. Also, the vulnerability V(H) (that is, the constant value c H (a j )) is multiplied by the estimated population P i、aj (T) for each age group, and the sum thereof is calculated. As a result, the vulnerability V(H) acts as a weight for each age group, and the formula is configured such that the influence of the age group with a greater degree of damage is greater in the sum as the degree of damage increases. In this way, by multiplying the value that comprehensively expresses the risk of the disaster and the sum of the estimated population P i、aj (T) to which the vulnerability V(H) is applied as a weight, the disaster risk R i (H i ;T), which indicates the possibility of how much human damage can occur due to a disaster in the future after a lapse of multiple years T, is calculated.

[0036] In this way, in the present embodiment, the disaster risk calculation unit 11 uses the vulnerability V(H) (that is, the constant value c H (a j )) as a weight coefficient for each age group, calculates the value obtained by multiplying the estimated population P i (T) (more specifically, P i、aj (T)) for each age group by the vulnerability V(H) (that is, the constant value c H (a j )), calculates the sum of the values, and calculates the disaster occurrence frequency Hi(S i >S;T) and the function f(S iBased on the above sum and, specifically, by multiplying these, the disaster risk R i (H i ;T) is calculated.

[0037] When the number of years elapsed T from the present is input by the user via an input device (not shown) such as a keyboard or a mouse, the disaster risk calculation unit 11 calculates the future disaster risk R i (H i ;T) for all points i within the specific area R. FIG. 14 is a diagram showing the disaster risk calculated for the year 2020 for each point within the specific area. FIG. 15 is a diagram showing the disaster risk calculated for the year 2050 for each point within the specific area. The disaster risk display unit 12 displays the disaster risk for each point i within the specific area R on an output device (not shown) such as a display. For example, in the case of evaluating the disaster risk after 5 years with the number of years elapsed T being 5 in 2015, as shown in FIG. 14, the disaster risk R i (H i ;T) for 2020 at each point i within the specific area R is evaluated and displayed. Also, in the case of evaluating the disaster risk after 35 years with the number of years elapsed T being 35 in 2015, as shown in FIG. 15, the disaster risk R i (H i ;T) for 2050 at each point i within the specific area R is evaluated and displayed.

[0038] Next, a disaster risk evaluation method using the above disaster risk evaluation system 1 will be described. First, the user of the disaster risk evaluation system 1 inputs the number of years elapsed T from the present via an input device (not shown) such as a keyboard or a mouse. The disaster risk calculation unit 11 determines, for each point i within the specific area R, the disaster occurrence frequency H i (S i (S>T;T) indicating the frequency of disasters occurring in the future until the lapse of multiple years T, and the estimated population P at the time when multiple years T have elapsed.i Based on (T) and vulnerability V(H), a coefficient indicating how vulnerable a person exposed to a disaster is to that disaster and how severe the damage to that person may be, disaster risk R is an index that indicates the extent of human damage that could be suffered by a disaster at location i after several years T have passed. i (H i Calculate T) (disaster risk calculation process). The disaster risk display unit 12 displays the disaster risk R for each point i within the specified area R. i (H i ;T) is displayed on an output device such as a display (not shown) (disaster risk display process).

[0039] The disaster risk assessment system 1 described above is a disaster risk assessment system that evaluates the disaster risk at a point L within a specific area R after several years have passed, and the disaster frequency H indicates the frequency at which a disaster will occur at point L in the future up to several years from now. i (S i >S;T) and the estimated population P after several years have passed. i、aj (T) and vulnerability V(H) (i.e., a constant value c), which is a coefficient that indicates how vulnerable a person exposed to a disaster is to that disaster and how great the extent of their damage may be. H (a j Based on the above, disaster risk R is an index that shows the degree of human damage that may be incurred by a disaster at location L after several years have passed. i (H i The system includes a disaster risk calculation unit 11 that calculates T, and a disaster risk display unit 12 that displays the disaster risk for point L. When evaluating disaster risk, which is an indicator of the extent of human casualties that may occur due to a disaster at a specific location L within a designated area R after several years have passed, the population of location L to be evaluated is required as input for processing. However, when evaluating disaster risk at location L after several years have passed, the population of location L may change over those years. Therefore, evaluating disaster risk after several years has passed based on the current population of location L at the time the disaster risk is being evaluated may not yield sufficient accuracy. In contrast, with the configuration described above, the disaster risk calculation unit 11 calculates disaster risk, an index indicating the extent of human casualties that may be incurred by a disaster at location L after several years have passed, based on the following: the frequency of disaster occurrence, which indicates how often a disaster will occur at location L over the next several years; the estimated population at the time after several years have passed; and vulnerability, which is a coefficient indicating how vulnerable people exposed to a disaster are to the disaster and how significant the extent of their damage may be. In this way, the disaster risk calculation unit 11 calculates disaster risk based on the estimated population several years after the present, rather than the current population. The disaster risk calculated in this way takes into account the population of location L in the future, several years after the present, rather than the current population, and therefore has higher accuracy compared to evaluating disaster risk based on the current population. Furthermore, the disaster risk calculation unit 11 evaluates disaster risk based on the estimated population at a point in time several years later, as well as the frequency of disaster occurrence and vulnerability, as described above. Therefore, the calculated disaster risk reflects the frequency of future disaster occurrences, the degree to which people exposed to a disaster are vulnerable to that disaster, and the extent to which the damage to those people may be. In this way, the accuracy of the disaster risk is further improved because it reflects both the frequency of disaster occurrences and the susceptibility of people to damage. In this way, it becomes possible to accurately assess the disaster risk at a specific location L within a designated area R when a disaster occurs several years later.

[0040] Also, the estimated population P i、aj (T) and vulnerability V(H) (i.e., constant value c) H (a j The )) is set for each age group, and the disaster risk calculation unit 11 uses vulnerability as a weighting coefficient for each age group, calculates a value obtained by multiplying the estimated population by vulnerability for each age group, calculates the sum of these values, and determines the disaster occurrence frequency H i (S i >S;T) and an indicator related to the intensity of the disaster (influence function f(S i Based on the sum and the above, the disaster risk is calculated. When a disaster occurs, it is thought that older people, for example, are more likely to suffer greater human casualties than younger people when exposed to the disaster. In contrast, with the above configuration, the estimated population and vulnerability are set for each age group, and the disaster risk calculation unit 11 uses vulnerability as a weighting coefficient for each age group, calculates a value by multiplying the estimated population and vulnerability for each age group, and calculates the sum of these values. The sum calculated in this way reflects the susceptibility and magnitude of damage for each age group, which have been adjusted for each age group by vulnerability. In this way, by calculating the disaster risk based on the sum calculated as described above and the frequency of disaster occurrence, it becomes possible to evaluate the disaster risk with greater accuracy. Furthermore, while the sum calculated as described above indicates the extent of human casualties in the event of a disaster, in the configuration described above, disaster risk is calculated based on this sum, along with indicators related to the frequency and intensity of disasters. In this way, since the frequency and intensity of disasters are reflected in the calculation of disaster risk, the disaster risk assessment system is further improved.

[0041] Furthermore, for multiple past disaster cases, the number of victims in each age group is obtained. For each of the multiple disaster cases, the number of victims in each age group is divided by the population of that age group at the location where the disaster occurred to calculate a division value. For each age group, the median of the division values ​​among the multiple disaster cases is calculated, and the ratio of the median of one age group to the median of another age group is calculated to determine vulnerability for each age group. With the above configuration, the number of victims for each age group is obtained for multiple past disaster cases. Since each of the multiple disaster cases obtained in this way may have occurred in different regions or time periods, the composition of the population affected by the disasters may also differ. In response to this, as described above, the number of victims for each age group in each of the multiple disaster cases is divided by the population of that age group at the location where the disaster occurred, thereby standardizing the number of victims for each age group in each of the multiple disaster cases. In this way, a value is calculated as the division value that excludes the influence of the population composition due to the region and time period in which the disaster occurred. Then, for each age group, the median of the division values ​​calculated as described above is calculated among the multiple disaster cases, and by calculating the multiplier of the median of one age group to the median of another age group, a representative value of the multiplier of the number of victims for each age group, which excludes the influence of the population composition due to the region and time period in which the disaster occurred, can be appropriately determined. By using the multiplier obtained in this way as the vulnerability for each age group, it becomes possible to evaluate disaster risk with greater accuracy.

[0042] Furthermore, the above-described disaster risk assessment method is a disaster risk assessment method that assesses the disaster risk at a point L within a specific area R after several years have passed, and includes a disaster risk calculation step that calculates the disaster risk, which is an index indicating the degree of human damage that may be suffered by a disaster at point L after several years have passed, based on the disaster frequency, which indicates the frequency of disaster occurrence at point L up to several years have passed, the estimated population at the time several years have passed, and vulnerability, which is a coefficient indicating how great the degree of damage to people exposed to and affected by the disaster may be, and a disaster risk display step that displays the disaster risk for point L. With the configuration described above, similar to disaster risk assessment system 1, it becomes possible to accurately assess the disaster risk at point L within a specific area R when a disaster occurs several years later.

[0043] It should be noted that the disaster risk assessment system 1 of the present invention is not limited to the embodiments described above with reference to the drawings, and various other modifications are conceivable within its technical scope. For example, a disaster risk assessment system may calculate disaster risks for multiple different types of disasters, such as earthquakes, floods, and tsunamis, and then, based on the disaster risks calculated for each of these disasters, calculate a total disaster risk that takes all disasters into account, and display this total value as the disaster risk. In this case, for example, let N be the total number of disaster types, and let the identifier k (=1 to N) represent each type of disaster. Here, for each disaster k, the intensity of the disaster at point i over the next T years is k S i However, the threshold of the intensity of a disaster that can result in human casualties k The probability value exceeding S k Prob( k S i > k It is expressed as S;T). Then, the frequency of disaster occurrence of disaster k. k H i ( k S i > kS;T) is the probability value of the disaster k, as shown in equations (7) and (8) below. k Prob( k S i > k S;T) is the probability value in all disasters. k Prob( k S i > k w is the value obtained by dividing by the sum of S;T). i ( k H i It can be defined as being proportional to ).

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[0044] In addition to the above, it is possible to select or replace the configurations listed in the above embodiments and modifications, or to change them to other configurations as appropriate. [Explanation of symbols]

[0045] 1. Disaster Risk Assessment System 13. Databases 11 Disaster Risk Calculation Department R Specific Area 12. Disaster risk display area L point

Claims

1. A disaster risk assessment system that evaluates the disaster risk at a specific location within a particular area after a period of time, A disaster risk calculation unit calculates the disaster risk, which is an index indicating the extent of human casualties that may be incurred by the disaster at the location after the aforementioned multiple years have elapsed, based on the following: the frequency of occurrence of the disaster at the location up to the aforementioned multiple years; the estimated population at the time the aforementioned multiple years have elapsed; and vulnerability, which is a coefficient indicating how vulnerable people exposed to the disaster are to the disaster and how great the extent of damage to those people may be. A disaster risk display unit that displays the disaster risk for the aforementioned location, A disaster risk assessment system characterized by having the following features.

2. The estimated population and vulnerability mentioned above are set for each age group. The disaster risk calculation unit uses the vulnerability as a weighting coefficient for each age group, calculates a value obtained by multiplying the estimated population by the vulnerability for each age group, calculates the sum of these values, and calculates the disaster risk based on the disaster frequency, the indicator related to the intensity of the disaster, and the sum. The disaster risk assessment system according to feature 1.

3. Regarding multiple past disaster cases, we obtained the number of victims for each age group. In each of the multiple aforementioned disaster cases, for each age group, the number of victims is divided by the population of that age group at the location where the disaster occurred, to calculate the division value. For each of the years, calculate the median of the division value among each of the multiple disaster cases. Calculate the ratio of the median value of one age group to the median value of another age group. By doing so, the aforementioned vulnerability is calculated for each era. The disaster risk assessment system according to feature 2.

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