A data-driven linear filtering method to recover microseismic signals from noisy data/observations based on statistics of background noise and observation, which are directly extracted from recorded data without prior statistical knowledge of the microseismic source signal. The method does not depend on any specific underlying noise statistics and works for any type of noise, e.g., uncorrelated (random/white Gaussian), temporally correlated and spatially correlated noises. The method is suitable for microquake data sets that are recorded in contrastive noise environments. The method is demonstrated with both field and synthetic data sets and shows a robust performance.

Provided is a technique that can suppress erroneous determination of noise as an earthquake in a seismic sensor and erroneous output of a shut-off signal. The seismic sensor includes: an earthquake determination unit configured to determine an occurrence of an earthquake based on acceleration measured in a determination period after shifting from a power saving mode to a measurement mode with higher power consumption when measured acceleration 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 determination period, when the earthquake determination unit determines that an earthquake has occurred. The seismic sensor causes output of a shut-off signal when the index value is equal to or larger than a threshold in the earthquake processing period. The seismic sensor further includes: a continuous earthquake determination unit configured to determine whether or not an earthquake has occurred, based on 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.

The present invention discloses a microseismic monitoring system, which includes at least a microseismic sensor, a push rod set at both ends of the microseismic sensor through the first connecting mechanism for sending the microseismic sensor into a monitoring hole, a guide mechanism installed on the push rod for guiding the microseismic sensor into the monitoring hole, and a microseismic monitoring computer connecting with the microseismic sensor signal. The microseismic sensor is reusable. The first connecting mechanism can make the push rod swing relative to the microseismic sensor. The guide mechanism is a three-roller guide mechanism. The present invention can satisfy the need of monitoring different locations in monitoring holes with large depths for multiple microseismic sensors, and solve problems of effective contact coupling between the microseismic sensors and monitoring holes, which improves the accuracy of microseismic monitoring and reduces the cost of a microseismic monitoring system.

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.

A test system for a microseismic test of rock mass fractures provided by the present invention includes at least one microseismic sensor, a push rod provided at two ends of the microseismic sensor through a connecting mechanism for feeding the microseismic sensor into a monitoring hole , an introducing mechanism mounted on the push rod for introducing the microseismic sensor into the monitoring hole, a hydraulic system providing support hydraulic oil for the microseismic sensor, a microseismic monitoring computer connected with the signal of microseismic sensor through; the microseismic sensor includes a microseismic probe, a holding component holding the microseismic probe, a support plate and a hydraulic support mechanism; the connecting mechanism can make the push rod swing relative to the microseismic sensor, and the introducing mechanism is three-rollers introducing mechanism.

Apparatus and methods are described, including identifying an arrival of a first arriving S-wave emitted from a seismic source at an array (120) of sensors (129, 140) in real-time, by continuously analyzing waveforms received by the sensors (120, 140), and continuously monitoring back-azimuth and slowness data within the detected waveforms. Arrival of a first arriving P-wave emitted from the seismic source at the array (120) of sensors (129, 140) is identified, based upon the back-azimuth and slowness data. Slowness and back azimuth of the first arriving P-wave are determined, by analyzing a waveform of the P-wave, and based upon the determined slowness of the first arriving P-wave, the arrival of the first arriving S-wave at the array (120) of sensors (129, 140) is identified. Other applications are also described.

A system and method for a distributed earthquake analysis and reporting system are provided. The system includes a facility control system at a facility that obtains earthquake information sent from one or more seismic sensors, and sends the earthquake information over a network directly or indirectly to other facility control systems. The facilities which include the facility control systems can be owned/operated by different business organizations or by the same organization, in examples. The facility control system at each facility responds to received earthquake information from the other facility control systems by configuring building systems such as public address systems to warn building occupants, industrial machine controllers to stop machinery, and elevator controllers to stop elevators at a nearest floor and open its doors, in examples.

A method for assessing a performance-based seismic design by setting a seismic risk starts from the exceedance probability of the performance level. The method is configured to determine the structural performance level by setting an exceedance probability, determine the seismic demand when the performance level is constant, set the exceedance probability of the seismic demand in combination with the seismic risk of a set earthquake to finally determine the ground motion input and establish a novel probabilistic seismic risk assessment method that reaches the performance level. The main control and objective of the design are significantly enhanced by using this method.

A mechanical-model based earthquake-induced landslide hazard assessment method in earthquake-prone mountainous area includes: obtaining the cohesion and internal friction angle through a geological map of the study area and a geotechnical physical parameter; obtaining simulated ground motions by combining a pulse-like ground motion effect model and a pulse-like ground motion response model; calculating slope permanent displacement according to the simulated ground motions, the cohesion, the internal friction angle and other parameters; obtaining a statistical relationship between the permanent displacement and a landslide probability according to permanent displacement data derived from historical earthquake-induced landslides and historical strong earthquake records; and predicting earthquake-induced landslide probability according to the slope permanent displacement and the statistical relationship between the permanent displacement and the landslide probability, and quantitatively evaluating earthquake-induced landslide hazard through the earthquake-induced landslide probability.

A valve controller device for controlling a set of one or more solenoid valves is provided. The valve controller comprises an accelerometer for making acceleration measurements in three directions comprising acceleration measurements in a vertical direction. The valve controller comprises a processing unit that determines the arrival of seismic P-waves when the ratio of vibrations' power in the vertical direction with respect to a sum of the vibrations' power in the three directions exceeds a first threshold. The processing unit then determines the arrival of seismic S-waves when the vector sum of the vibrations' power in the three directions exceeds a second threshold. The processing unit then determines the arrival of seismic surface waves when the vector sum of the vibrations' power in the three directions exceeds a third threshold. The processing unit then sends one or more signals to close the set of solenoid valves.