Seismic and micro-seismic monitoring plays an important role across many engineering disciplines.
From strong motion / earthquake hazard evaluation; to structural health assessments, e.g. for buildings, bridges and dams; to blasting characterization needs in mining. This data provides valuable insight about patterns of stress distribution, rock mass, faults and fracture networks in the ground and structures. In correlation with other types of geotechnical data – e.g. hydrology data from piezometers, displacement data from inclinometers, or ground movement data from surveys – a complete picture begins to emerge as to the cause and effect of natural or man-made subsurface conditions.
Canary Systems’ vertically integrated solutions for data acquisition allow for the seamless combination of seismic or micro-seismic data with other sensor types in a single platform, and has been applied successfully in many projects across different markets, including in Dam Safety, Mining, and Structural monitoring.
MultiLogger® Suite allows for direct integration with seismic recorders and accelerographs from various manufacturers, including Kinemetrics, RefTek, and Syscom. In addition, it supports external integration with a multitude of additional sensors and data networks, such as the USGS Earthquake Hazard Program.
Specialized charting and visualization options in MLSuite® allow for plotting of seismic event data in many ways. The customizable Event Chart is designed to process and plot high-speed event data captures, and supports the standard USGS data types and formats. It provides for calculating velocity and displacement, making linear baseline corrections, applying instrument correction, filtering high frequency and/ or low frequency content from the time series, calculating the Fourier amplitude spectrum, and calculating response spectra.
Complex data analysis is made possible by a flexible calculation engine which includes built-in statistical prediction functions.
CASE STUDY – DAM SAFETY SEISMIC WARNING SYSTEM
The Cobble Mountain Reservoir Dam is located in Massachusetts. The Seismic Warning System consists of a Kinemetrics Altus Digital Recorder connected to a Canary Systems MLDAQ data acquisition base station.
The Kinemetrics Altus Digital Recorder triggers an alarm in the event of seismic activity above a predefined threshold, which signals to the datalogger to initiate storage of pore pressure/level/temperature measurements at a 1 minute interval for a period of 24 hours, in addition to recording the event data itself (at a sample rate of 200 SPS). The event data includes 5 seconds of pre-event and 25 seconds of post-even seismic data for each exceedance event. It also activates a wireless voice messaging system to alert site personnel via telephone.
CASE STUDY – UNDERGROUND MINE IN SOUTHEAST ASIA
At a large mine in Southeast Asia with ongoing open pit and underground operations in close proximity, continuous passive micro-seismic monitoring produces a constant stream of micro-seismic event data including Northing, Easting, Depth, and Moment Magnitude. Advanced microseismic analysis is used to reveal detailed information about the microseismicity of the area and how the rock is responding to mining activities, leading to increased efficiency and optimized operations. Micro-seismic events are plotted in time using MLSuite®. Statistical analysis using the built-in Inverse Poisson function is run daily as an automated report, and used to automatically determine the safety of operations in several zones of the underground area for the given day. Alarms and notifications based on the analysis are set up to automatically notify site personnel of the current safety level and if operations are to resume or be suspended for the day.