Methods for detecting earthquake events

Abstract

To provide a method for detecting an earthquake event, in particular, a method for detecting foreshocks for earthquake prediction, and an ultrasonic water meter adapted to execute the method.SOLUTION: The present invention relates to a method for detecting an earthquake event with a plurality of sensors, in particular, a method for detecting foreshocks for earthquake prediction, where at least a portion of a water pipe network in which the sensors are arranged is used for detection, the earthquake event is acoustically detected, and the sensors are acoustic sensors.SELECTED DRAWING: Figure 2

Description

Technical Field

[0005] ,

[0001] The present invention relates to a method for detecting seismic events, in particular a method for detecting foreshocks for earthquake prediction, and an ultrasonic water meter adapted to perform this method.

Background Art

[0002] An earthquake is a sudden shaking of the ground caused by seismic waves passing through the rocks of the earth. Such seismic waves occur when the energy stored in the earth's crust is suddenly released. Usually, it occurs when large rock masses that are pushing against each other suddenly brake and slide. In many cases, there are related foreshocks both in time and space before an earthquake occurs. These earthquakes and foreshocks generate acoustic signals throughout the spectrum, that is, in the very low frequency sound, ultrasonic, and audible range. In order to be able to give an early warning of an earthquake, it has always been the goal to predict such an earthquake.

[0003] AU2016100644A4 discloses an earthquake prediction and warning system based on the monitoring and analysis of underground ultrasonic waves. This system requires a large number of ultrasonic sensors distributed over a wide area. It is necessary to monitor and evaluate the signals of these ultrasonic sensors, which requires a great deal of technical effort. Furthermore, there is also the problem that these ultrasonic sensors need to be arranged in appropriate places in the ground, especially in hard rock layers, rock masses, etc. where ultrasonic waves can propagate.

Summary of the Invention

[0004] The object of the present invention is to reduce the technical effort. A further object of the present invention is to cover the entire area without problems of acoustic coupling.

[0005] The solution according to the present invention is a method for detecting seismic events, in particular a method for detecting foreshocks for earthquake prediction, in which the seismic event is detected by a plurality of sensors. According to the present invention, at least a part of the water pipe network where the sensors are arranged is used for detection.

[0006] The main idea of ​​this invention is to use water supply networks, which are likely installed in many parts of the world for supplying drinking water, household water, or industrial water. Such water supply networks typically consist of a network of water pipes that carry water under pressure. Water pipes are made of rigid plastic or metal and transmit sound waves. Metal pipes, in particular, are ideal for transmitting mechanical / acoustic waves generated in the ground by seismic events. Since these water pipe networks are everywhere, they can be used at no additional cost. Of course, if sensors installed in the water pipe network cannot be used, sensors for detection will need to be placed in the water pipe network.

[0007] Preferably, these seismic events are detected acoustically because it is the easiest way to detect them. Acoustic sensors are required for acoustic detection.

[0008] Civilized countries have a water supply network for drinking water or household water. This water supply needs to be paid for according to consumption. This is why thousands of water meters are installed in these water supply networks. Previously, mechanical water meters were used, but now there are electronic water meters that transmit signals about water consumption wirelessly to a concentrator (centralized device), where this data is further processed and evaluated. These electronic water meters are often equipped with ultrasonic sensors. Such water meters are called ultrasonic water meters and measure consumption using, for example, two ultrasonic sensors in the pipe. If these ultrasonic water meters are used in a water supply network, it is particularly advantageous to use those ultrasonic sensors to detect seismic events. There are many sensors that can be used to detect seismic events, and the additional cost is minimal. There may be additional costs for modifying the hardware and / or software of these ultrasonic water meters. However, the major advantage is to use hardware and / or software that is already there and is being used for leak detection and / or flow rate measurement. This hardware and / or software for detecting leaks in the water pipeline network is an add-on feature of a supersonic water meter, which can be adapted fairly easily to detect earthquake events.

[0009] In many cases, water pipeline networks extend over long distances (more than 10 km), making it too long to pinpoint the exact location of an earthquake. Therefore, it may be advantageous to divide the water pipeline network into areas and assign ultrasonic water meters to those areas. In this way, the signals from the ultrasonic sensors of the ultrasonic water meters can be evaluated in each area to determine the center and direction of an earthquake.

[0010] When using ultrasonic sensors in ultrasonic water meters for detection, a potential issue is that the data from the ultrasonic water meter is transmitted at specific time intervals rather than continuously. This is done to conserve electrical energy, which is very limited for batteries that are supposed to last for more than 16 years. For this reason, it is convenient to perform a pre-evaluation of the ultrasonic sensor signal in the ultrasonic water meter, and for the ultrasonic water meter to transmit the pre-evaluated data to the concentrator. This is useful when the electrical energy required for pre-evaluation in the ultrasonic water meter is less than the electrical energy required to continuously transmit this data to the concentrator. This may change as the technical conditions of electrical and electronic components change.

[0011] These concentrators are configured to receive data from, for example, 1000 ultrasonic water meters and are connected to a power grid. This is why the evaluation and correlation of signals received from ultrasonic water meters should be favorably processed by the concentrators.

[0012] Further evaluation of these signals from ultrasonic water meters in each area is useful, and the typical signal progression for earthquakes in each area is used as the basis for the evaluation. These signal progressions need to be adapted to the geographical location and / or time series of each area.

[0013] Each group of concentrators, which receives signals from a group of ultrasonic water meters, is data-connected to a headend system. Since all data is collected in the headend system, it is advantageous for this further signal evaluation to be performed in the headend system.

[0014] Thus, it is useful to use a system based on an ultrasonic water meter, concentrator, and headend system, performing preliminary data evaluation within the ultrasonic water meter, data evaluation in the concentrator, and further signal evaluation in the headend system.

[0015] When detecting foreshocks for earthquake prediction, reliability of the prediction is crucial. That is, only detected earthquake events that can be reliably identified as foreshocks should trigger an earthquake alarm. Therefore, according to this invention, a two-stage method is used to detect foreshocks: in the first stage, a signal pattern characterizing the foreshock is detected, and in the second stage, the detected pattern is verified. The alarm is triggered (activated) only if both stages match. For the signal evaluation in the first stage, it is advantageous to use a neural network to support this evaluation. It is often unclear whether a signal pattern actually corresponds to a detected foreshock, but using a neural network can make this determination more reliable. Alternatively or additionally, verification of the detected pattern can be performed by comparing it with signals from further sensors other than ultrasonic sensors. These sensors are often different from ultrasonic sensors, and since earthquake foreshocks typically generate infrasound, it is advantageous that these sensors are infrasound sensors. These sensors could be, for example, accelerometers.

[0016] When an ultrasonic water meter is used to detect seismic events in a predetermined manner according to the present invention, an ultrasonic water meter adapted to perform this method must be used. In the simplest sense, this means that the software within the meter is adapted to perform a preliminary evaluation of the detected signal. Furthermore, the hardware may also be adapted, possibly including internal digital electronics and / or additional internal sensors. This could be, for example, a microphone. Advantageously, since ultrasonic water meters are fitted with infrasound sensors, there are two types of sensors, which can make foreshock detection more reliable.

[0017] The use of the water pipe network in which the sensors are installed is described below based on the diagram. [Brief explanation of the drawing]

[0018] [Figure 1] This diagram shows the extent and complexity of the water distribution network in a simplified schematic representation. [Figure 2] This diagram shows an earthquake detection system that utilizes a water pipe network. [Figure 3] This is a schematic diagram showing the configuration of an ultrasonic water meter equipped with leak and seismic event detection capabilities. [Figure 4] This is a schematic cross-sectional view of an ultrasonic water meter equipped with three sensors. [Modes for carrying out the invention]

[0019] Figure 1 shows the main water pipes of a typical water pipeline network located in an area encompassing a city. The direction of water flow is indicated by arrows. Each of these main water pipes supplies water to many homes, each equipped with an ultrasonic flow meter. These ultrasonic water meters are well-known and common. For example, the Kamstrup Multical type. This water meter has two ultrasonic sensors built in to measure flow rate. The idea is to use these ultrasonic sensors inside the flow meter to detect seismic events.

[0020] To enable the identification of the location of seismic events, these ultrasonic water meters 10 are grouped into areas. As schematically seen in Figure 2, there are a first detection area 1, a second detection area 2, and a third detection area 3. All of them are connected to water pipes 4 of the water network 5, as shown in Figure 1. These areas may contain up to 1000 or more ultrasonic water meters 10, each transmitting its data to a concentrator 6 at time intervals, where the received data is processed and evaluated, and then transmitted to one or more headend systems 7, where earthquake prediction and optional alarms are performed. A seismic event, such as a typical foreshock, is represented by the symbol 8 in Figure 2. This event 8 generates sound waves 9 that spread throughout the water network and areas 1, 2, and 3 of the water network 5. These sound waves 9 become stronger or weaker depending on the distance to the center.

[0021] In each ultrasonic water meter 10, these sound waves 9 are detected with an intensity corresponding to the distance between them and areas 1, 2, and 3 where they are located. The signals 14 generated by the ultrasonic sensors T1 and T2 of the ultrasonic water meter 10 are pre-evaluated within the water meter using the same electronic components C1 and C2 used for leak detection and / or flow rate measurement. The software is adapted accordingly. These pre-evaluated data are transmitted from the ultrasonic water meter 10 to concentrators 6 assigned to the group of meters 10. In this embodiment, each area 1, 2, and 3 has its own concentrator 6. These are arranged here only for the sake of simplicity and may differ. These concentrators 6 receive the pre-evaluated signals 12, 13, and 14 from the water meter 10 and process and evaluate these signals. In these concentrators 6, a first level of pattern recognition is performed.

[0022] The concentrators 6 transmit their signals to one or more headend systems 7, where level 2 signal detection takes place. In these headend systems 7, the signals from all concentrators 6 are evaluated, and further, it is determined whether these detected seismic events are foreshocks. If the latter is confirmed, an alarm is generated. This second level of detection in the headend systems 7 correlates the signals from all concentrators 6, and, for example, arranges a validation check. Furthermore, depending on the signal intensity of arrays 1, 2, and 3, the center of the foreshock 8 and at least the direction in which it originated can be calculated.

[0023] Furthermore, to confirm that the detected signal 14 is a type of seismic event and not a disturbance, there may be at least some ultrasonic water meters 10 equipped with ultra-low frequency sound sensors T3.

[0024] Figure 3 shows the structure of the ultrasonic meter 10. The ultrasonic meter 10 is incorporated in a water pipe 4 having a flow direction 11. A part of the water pipe 4 is an integrated part of the ultrasonic water meter 10. On this wall part, a first ultrasonic sensor T1 and a second ultrasonic sensor T2 spaced apart are arranged. Further, there are a first reflector R1 assigned to the first ultrasonic sensor T1 and a second reflector R2 assigned to the second ultrasonic sensor T2. The ultrasonic sensors T1 and T2 are connected to an evaluation electronic device C1 for measuring the flow rate and an evaluation electronic device C2 for determining leakage and seismic events. The electronic device C1 transmits a signal 12 corresponding to the flow rate, and the electronic device C2 transmits signals 13 and 14. The signal 13 is a leakage detection signal, and the signal 14 is a seismic event detection signal. These signals 12, 13, 14 that can be further processed are wirelessly transmitted to a concentrator 6, where they are further processed and then transmitted to a head-end system 7.

[0025] Figure 4 shows an ultrasonic water meter 10 that is adapted not only to detect seismic events by ultrasonic sensors T1 and T2 and evaluation electronic devices C1 and C2 but also includes an additional sensor T3 that is an ultra-low frequency sound sensor. This sensor T3 can be arranged on the wall part of the water pipe 4, or alternatively, it can be arranged on the wall part of the housing of the ultrasonic water meter 10. Using this ultra-low frequency sound sensor T3, the seismic events detected by the ultrasonic sensors T1 and T2 of the ultrasonic water meter 10 can be evaluated.

Explanation of Signs

[0026] 1 First detection area 2 Second detection area 3 Third detection area 4 Water pipe 5 Water pipe network 6 Concentrator 7 Head-end system 8 Preshock 9 Wave 10 Ultrasonic water meter 11 Flow direction 12 Flow signal 13. Leak detection signal 14. Earthquake Event Signals T1 First ultrasonic sensor T2 Second ultrasonic sensor T3 Infrasound Sensor R1 First Reflector R2 Second Reflector C1 Electronic device for measuring flow rate C2 Electronic equipment for determining water leaks and seismic events

Claims

1. A method for detecting foreshocks for earthquake prediction using multiple sensors, characterized in that at least a portion of a water pipe network (5) in which multiple ultrasonic water meters (10) are installed is used for detection, ultrasonic sensors (T1, T2) within the ultrasonic water meters (10) are used as sensors for foreshock detection, the water pipe network (5) is divided into multiple areas (1, 2, 3), multiple ultrasonic water meters (10) are assigned to the areas in which they are installed, each area is provided with a concentrator (6) that receives signals related to water consumption from the multiple ultrasonic water meters (10) installed therein, and the evaluation of sensor signals for detecting foreshocks is performed area by area on a headend system (7) data-connected to a group of concentrators (6), and the typical signal progression for earthquakes in each area is used as the basis for the evaluation.

2. The method according to claim 1, characterized in that existing hardware (C1, C2) and / or modified software are used for detecting foreshocks, and the hardware and / or software are also used for detecting water leaks and / or measuring flow rates by an ultrasonic water meter (10).

3. The method according to claim 1 or 2, characterized in that seismic event detection is performed in an ultrasonic water meter (10), and the ultrasonic water meter (10) transmits a seismic event detection signal to a concentrator (6).

4. The method according to claim 3, characterized in that the correlation of earthquake event detection signals received from a plurality of ultrasonic water meters (10) is evaluated by a concentrator (6).

5. The method according to any one of claims 1 to 4, characterized in that a two-stage method is used to detect a foreshock, in which a signal pattern characterizing the foreshock is detected in the first stage, and an alarm is triggered after the detected pattern is verified in the second stage.

6. The method according to claim 5, characterized in that the first step is performed using a neural network.

7. The method according to claim 5 or 6, characterized in that the verification is performed by a further signal from a non-ultrasonic sensor.

8. The method according to any one of claims 5 to 7, characterized in that the verification is performed using further signals from an ultra-low frequency sound sensor (T3).

Images