A building integrity assessment system includes: an earthquake detector including: a building bottom sensor at a bottom of a building and that detects acceleration and an earthquake early-warning receiver that receives an earthquake early warning; a cloud computer; and sensors disposed at a plurality of positions in the building and that measures an influence of an earthquake on the building at each of the positions and wirelessly transmits measurement results to the cloud computer. The cloud computer estimates and evaluates the integrity of the building based on the measurement results. In response to the building bottom sensor detecting preliminary tremors or the earthquake early-warning receiver receiving the earthquake early warning, the plurality of sensors measures the influence of the earthquake on the building from a time before a major motion arrives at the building to a time after the arrival.

An earthquake sensing module includes an acceleration sensor configured to detect accelerations on a plurality of detection axes, a module control unit configured to control the acceleration sensor, and a module storage unit configured to store state information of the acceleration sensor.

A seismic sensor includes a measurement unit configured to measure acceleration; an earthquake determination unit configured to determine whether or not an earthquake has occurred based on the acceleration measured in a predetermined determination period; an index calculator configured to calculate an index value indicating a scale of an earthquake in an earthquake processing period after the predetermined determination period, when the earthquake determination unit determines that an earthquake has occurred; a continuous earthquake determination unit configured to determine whether or not an earthquake has occurred, based on the acceleration measured in the earthquake processing period; and a shut-off determination unit configured to inhibit output of the shut-off signal regardless of the index value when the continuous earthquake determination unit determines that no earthquake has occurred.

A seismic warning system comprises: a plurality of sensors, each sensor sensitive to a physical phenomenon associated with seismic events and operative to output an electronic signal representative of the sensed physical phenomenon; a data acquisition unit communicatively coupled to receive the electronic signal from each of the plurality of sensors, the data acquisition unit comprising a processor configured to estimate characteristics of a seismic event based on the electronic signal associated with a P-wave from each of the plurality of sensors; and a local device communicatively coupled to the data acquisition unit. The plurality of sensors, the data acquisition unit and the local device are local to one another.

A device and method for receiving real-time warning messages about a hazardous situation, for which an alert or a mitigating control action may be warranted, with the means to measure the effects forecasted by the parameters contained in the warning messages, adjust the parameters to more accurately reflect local conditions, and provide feedback about the performance and accuracy of the system sending the warning messages.

A high-power seismic wave early warning method is provided to use an earliest-arriving seismic wave to estimate a maximum power value of a later-arriving high-power seismic wave for a target site. When the estimated maximum power value of the later-arriving high-power seismic wave is greater than a warning value, an earthquake early warning is transmitted to an earthquake early warning device that is located at the target site.

A seismic sensor 10 comprises an acceleration acquisition unit 21, an acceleration waveform generation unit 22, a frequency sensing unit 24, and an earthquake determination unit 25. The acceleration acquisition unit 21 detects vibration and measures the acceleration of the vibration. The acceleration waveform generation unit 22 generates an acceleration waveform that indicates the relation between the elapsed time and the acceleration measured by the acceleration acquisition unit 21. The frequency sensing unit 24 senses the frequency of the acceleration waveform generated by the acceleration waveform generation unit 22 using a zero-crossing method. The earthquake determination unit 25 determines whether or not there is an earthquake on the basis of the frequency sensed by the frequency sensing unit 24.

A seismic warning system comprises: a plurality of sensors, each sensor sensitive to a physical phenomenon associated with seismic events and operative to output an electronic signal representative of the sensed physical phenomenon; a data acquisition unit communicatively coupled to receive the electronic signal from each of the plurality of sensors, the data acquisition unit comprising a processor configured to estimate characteristics of a seismic event based on the electronic signal associated with a P-wave from each of the plurality of sensors; and a local device communicatively coupled to the data acquisition unit.

Provided is a technique that can more reliably suppress erroneous determination of noise as an earthquake, in a seismic sensor. The seismic sensor operates in a power saving mode and a measurement mode with higher power consumption than that of the power saving mode. The seismic sensor includes: a measurement unit configured to measure acceleration; an earthquake determination unit configured to determine whether or not an earthquake has occurred based on the acceleration measured in a predetermined determination period after shifting to the measurement mode when shifting from the power saving mode to the measurement mode in a case where acceleration measured by the measurement unit exceeds a predetermined threshold; and an index calculator configured to calculate an index value indicating a scale of an earthquake in an earthquake processing period after the predetermined determination period, when the earthquake determination unit determines that an earthquake has occurred. The earthquake determination unit determines an occurrence of an earthquake based on the presence or absence of a pulse waveform in a waveform of acceleration measured in the determination period, and/or a frequency characteristic or a convergence characteristic after the pulse waveform in a waveform of the acceleration.

Erroneous determination of noise as an earthquake is reduced in a seismic sensor. The seismic sensor operates in a power saving mode and a measurement mode in which power consumption is larger than that in the power saving mode. The seismic sensor includes: a measurement unit configured to measure acceleration; an earthquake determinator configured to transition from the power saving mode to the measurement mode when the acceleration measured by the measurement unit exceeds a predetermined threshold, to determine whether an earthquake is generated based on the acceleration measured in the measurement mode; and an index calculator configured to calculate an index value indicating a scale of the earthquake when the earthquake determinator determines that the earthquake is generated. The earthquake determinator determines whether the earthquake is generated by determining whether a predetermined condition is satisfied, the predetermined condition being determined based on the acceleration measured in at least one determination period, each determination period into which a period after the power saving mode transitions to the measurement mode is divided being set to a processing unit, and the measurement mode transitions to the power saving mode when the earthquake determinator determines that the earthquake is not generated.