Seismic Sensor Orientation Determination Using Microseism Records
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for accurately determining the orientation of seismic sensors, especially borehole seismometers, face challenges due to incorrect installation directions and reliance on earthquake signals or ambient noise, which can be time-consuming and prone to errors.
Innovation Solution
A standardized remote determination system and method that combines earthquake waveform and microseism record analysis to estimate seismic sensor orientation, using a control server with database functions, including data collection, analysis, reference sensor selection, misorientation angle determination, and final orientation value calculation, to improve accuracy and speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If borehole seismometers are installed, then seismic monitoring capability is improved, but installation direction accuracy deteriorates due to difficulty in setting correct orientation
Solution Approach 1:
The system performs preliminary orientation determination using microseism records before actual seismic monitoring begins. By analyzing microseism data to calculate the sensor's azimuth and inclination angles in advance, the system establishes the correct orientation reference frame prior to processing earthquake signals, thereby compensating for installation direction errors
Solution Approach 2:
The system introduces microseism records as an intermediary medium to determine sensor orientation. Instead of directly relying on installation precision, the system uses ambient microseism signals as a reference to calculate the sensor's actual orientation, serving as a mediator between the installed sensor and the true geographic coordinate system
2Measurement precision
If traditional earthquake signal-based orientation determination is used, then orientation can be determined, but time consumption increases due to waiting for suitable earthquake signals
Solution Approach 1:
The system performs orientation determination using microseism records before actual seismic monitoring begins. By analyzing microseism data to calculate the sensor's azimuth and inclination angles in advance, the system establishes the correct orientation reference frame prior to processing earthquake signals, thereby compensating for installation direction errors
Solution Approach 2:
The system utilizes continuous microseism records that are always present in the environment, eliminating the need to wait for intermittent earthquake events. Microseism signals provide a continuous source of orientation information, allowing immediate orientation determination upon sensor installation
3Measurement precision
If multiple orientation determination methods are used, then accuracy is improved, but system complexity increases
Solution Approach 1:
The system merges microseism-based orientation determination with earthquake signal processing into a unified workflow. The orientation angles calculated from microseism records are directly applied to correct the orientation of subsequent earthquake signal analysis, combining two functions into an integrated system that reduces overall complexity
Solution Approach 2:
The microseism analysis module serves multiple functions: it determines both azimuth and inclination angles, establishes the orientation reference frame, and provides calibration data for subsequent earthquake signal processing. This multi-functional approach eliminates the need for separate orientation determination systems
Data Source
AI summary
A remote determination system of seismic sensor orientation comprises: a data collection unit that receives earthquake waveforms and microseism records; a data analysis unit that analyzes earthquake P-waves and earthquake Rayleigh-waves of the earthquake waveforms and analyzes microseism of the input microseism records; a reference seismic sensor selection unit that selects a reference seismic sensor using analysis results derived from the data analysis unit; a misorientation angle determination unit that determines a misorientation angle of a target seismic sensor, using an apparent radial direction determined through microseism analysis and the reference seismic sensor; and a final representative value determination unit that determines a final representative value of a seismic sensor orientation, by collecting a seismic sensor orientation estimate from the earthquake P-wave analysis, a seismic sensor orientation estimate from the earthquake Rayleigh-wave analysis, and a seismic sensor misorientation angle determination value from the misorientation angle determination unit.