An earthquake prediction device comprises a predicted value calculation unit 16 that calculates, from a prediction formula below, a predicted value (MMIap) indicating a predicted intensity of a ground motion on the Modified Mercalli Intensity scale, using a maximum acceleration value (Aumax), which is a maximum absolute value among absolute values of vertical acceleration component of the ground motion, after a sensor starts detecting the ground motion caused by an earthquake. The prediction formula is: MMIap=a log.sub.10(Aumax)+a.

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 that suppresses power consumption operates in a power-saving mode and a measurement mode in which the power consumption is larger than that in the power-saving mode. The seismic sensor includes a measurement unit that measures an acceleration, a filtering unit that, if the acceleration measured by the measurement unit exceeds a predetermined threshold, causes a shift from the power-saving mode to the measurement mode to be performed, and performs filtering on the measured acceleration, an earthquake determination unit that determines whether or not an earthquake has occurred based on the filtered acceleration, and an index calculation unit that, if where the earthquake determination unit determined that an earthquake has occurred, calculates an index value indicating the scale of the earthquake. A shift from the measurement mode to the power-saving mode is performed if the earthquake determination unit determined that no earthquake has occurred.

The invention falls within the field of the techniques for manufacturing seismic monitoring systems and is applicable to structures related to civil engineering. The accelerometric sensor comprises one or more accelerometers (2a, 2b); a main microprocessor (7); a control microprocessor (8); a temperature sensor (3); a CAN bus driver (4); two connectors (5), one input and one output, of a CAN bus line; an input clock circuit (11); an error signaling circuit (10); a power supply unit (9); a container element (12), which at its interior contains the above components.

A method of modeling an aquatic environment or locating an acoustic source in the aquatic environment. A range-dependent medium is approximated in terms of a series of range-independent regions and obtaining single-scattering solutions across the vertical interfaces between regions. One or more acoustic waves are propagated from a known acoustic source through the range-dependent medium to one or more known seismoacoustic receivers to model iteratively the various solid and liquid layers of the range-dependent medium. Alternatively, one or more acoustic waves are reverse-propagated from one or more known seismoacoustic receivers through the range-dependent medium to determine whether an acoustic source is present within a user-defined range.

In some aspects, a closed boundary is computed based on locations and location-uncertainty domains of microseismic events associated with a stimulation treatment of a subterranean region. The closed boundary encloses the locations and respective location-uncertainty domains of multiple microseismic event data points. An error bound of a stimulated reservoir volume (SRV) for the stimulation treatment is identified based on the closed boundary.

A vibration detection system includes a seismic source device that generates a vibration wave repeated with a predetermined period, a vibration receiving device that receives a response wave due to the vibration wave transmitted via the ground, and a signal processing apparatus that processes measured vibration signals received by the vibration receiving device. The signal processing apparatus includes a separating part that separates individual periodic signals having a period according to a periodicity of the vibration wave generated by the seismic source from the measured vibration signals, the calculating part that calculates the standard periodic signal from the separated individual periodic signals, and the generating part that subtracts the standard periodic signal from the measured vibration signals and generates differential signals.

In some aspects, reservoir characterizations of subterranean regions can be enhanced by using realtime fracture matching techniques for capturing the time dependent evolution of fracture parameters based on the occurrence of the time microseismic events generated by stimulation treatments. These microseismic events may further be used to determine hydraulic fracture planes, identify areas of concentration of high density microseismic events, identify and analyze complex fracture networks, and use these and other techniques to enhance the reservoir characterization.

A method of modeling an aquatic environment or locating an acoustic source in the aquatic environment. A range-dependent medium is approximated in terms of a series of range-independent regions and obtaining single-scattering solutions across the vertical interfaces between regions. One or more acoustic waves are propagated from a known acoustic source through the range-dependent medium to one or more known seismoacoustic receivers to model iteratively the various solid and liquid layers of the range-dependent medium. Alternatively, one or more acoustic waves are reverse-propagated from one or more known seismoacoustic receivers through the range-dependent medium to determine whether an acoustic source is present within a user-defined range.

Power consumption of a seismic sensor is suppressed. The seismic sensor is operated in a power-saving mode and a measuring mode in which the power consumption is larger than that of the power-saving mode. The seismic sensor includes: a measuring part configured to measure an acceleration; an index calculator configured to transition from the power-saving mode to the measuring mode to calculate an index value indicating a size of an earthquake when the acceleration measured with the measuring part exceeds a first threshold; and a threshold adjuster configured to change the first threshold so as to increase the first threshold relative to a predetermined reference value when a tendency of the acceleration measured with the measuring part satisfies a predetermined condition.