20 documentos marcados com "Sensitivity Analysis"

The excavation hazard is calculated on minodes that represent underground tunnels as a series of connected nodes. For more information on minodes and to find out how to create or update them, go to this page: Minode Generator

Grid & Plane Setup window

You can pick any grid cell to view the frequency magnitude chart of events found in the local area. This is the b-value used for this grid point. The b-value is a very sensitive parameter in hazard calculations, and there are cases where the automatic FM modelling algorithm may not work well. There are several markers to help identify potential areas where the FM model may not represent the data accurately:

If you pick a minode in the 3D View, the grid point sources that contribute to the hazard at that minode will be plotted, scaled by how much they contribute. Theoretically, every grid point contributes to the hazard at a minode, but there is an accuracy threshold applied with a minimum probability to speed up the calculations. Increasing the accuracy will result in more contributing grid point sources.

You can plot the GMPE in a couple of different ways:

Overview

Probabilistic seismic hazard evaluation based on grid and spatial methods.

The hazard assessment app is designed to be simple to use but beneath the interface is a lot of complexity. It is important to be familiar with the underlying calculations and ensure that you are aware of the assumptions and limitations of the analysis. The calculations have been described in the linked pages below.

There are three types of isosurfaces that can be plotted in the Hazard Isosurfaces window. The details behind the calculation of each parameter is linked in the pages below:

Grid Definition

Grid & Plane Setup window

This window is used to assess the event location and mechanism quality. As events move away from the seismic array, the relative location error for a given magnitude is expected to increase, as well as the confidence in the location accuracy.

This window is used to investigate tagged blast locations from the events database and compare them with the blast locations set in the Blasts table to determine potential accuracy or offset issues with the system. In order to conduct this analysis, you first need to have tagged blasts. For IMS users, this information isn’t imported automatically. Please contact them to obtain the event tags database. For ESG users, the tags are imported automatically. You will however need to verify the meaning of these events to make sure they pass the quality filter.

How b-value sensitivity affects seismic hazard calculations and event rates.

This window is set up to conduct sensitivity analysis based on the trendline fit obtained in the previous window. It allows you to exclude current sensors and add planned sensors to see how the sensitivity changes across your mine.

This window is used to set the different variables to calculate the trendline in your data to be able to do the sensitivity assessment. Simply follow the steps through the window menu at the top (see figure).

The System Design app is used for analysing the seismic system design (historical, current and future). It is set up with various tools to assess system sensitivity ($M_$) and location and mechanism quality. Follow the links in the Key Learning Process section for the documentation on each window.

Assists with seismic monitoring network planning, sensor placement optimisation, coverage evaluation, and system sensitivity assessment.

A key criteria when designing a seismic system is establishing the lowest magnitude that the system can reliably record ($M$), referred to as the system sensitivity. The $M{min}$ the system is designed for can vary in space and time as it will depend on the application of the system (Rock mass monitoring, Hazard assessment, Damage location).

Hazard can be tracked over time by specifying a number of time steps and a step interval. The back analysis tool will step the backdate backward through time and summarise the hazard within each mining volume. Mining volumes can be defined in the Configuration area (link to filter volume editing page). The hazard within each mining volume is calculated by accumulating the hazard within each grid cell or for each minode within the volume.