Volume Data Extraction Tool Guide

The Volume Data Extraction Tool provides customized access to CVM (Community Velocity Model) datasets. This interface allows you to specify geographic parameters to retrieve the needed subset of data. The interface includes a 3D map that displays current Community Fault Model data such as CRESCENT Cascadia fault traces, fault surfaces, the Cascadia subduction interface, and the seismicity of the area in addition to the selected CVM boundaries. This map is designed to aid in highlighting the Community Fault Model (CFM) features within the CRESCENT study area to assist in subsetting the model to focus on areas of interest with specific CFM features.

Model Resolutions:

Each model has its own native resolution, which is described by the geospatial global attributes in the and GeoCSV files.

The horizontal resolution is determined by the geospatial_lat_resolution and geospatial_lon_resolution attributes, which specify the spacing between grid points in the latitude and longitude directions, respectively. The vertical resolution is defined by the geospatial_vertical_resolution attribute, indicating the spacing in the depth or height dimension.

The geographic extent of the model is outlined by the attributes geospatial_lat_min, geospatial_lat_max, geospatial_lon_min, geospatial_lon_max, as well as geospatial_vertical_min and geospatial_vertical_max. These attributes define the model's boundaries in terms of latitude, longitude, and vertical dimensions.

For example, a model with a latitude resolution of 0.5°, a longitude resolution of 0.5°, and a vertical resolution of 10 meters would have a grid with a horizontal resolution of 0.5° x 0.5° and a vertical resolution of 10 meters. These attributes ensure that the model's spatial resolution and extent are clearly defined for users.

Key features of the interface map include:

• CRESCENT Study Area: The boundaries of the CRESCENT study area are outlined in cyan, demarcating the focus area of the study.
• 3D Model Outline: The 3D outline of the selected CVM model is also displayed in cyan, allowing users to visualize the spatial extent and orientation of the model within the study area.
• Selected Model Extent: The selected model extent is shown in blue and can be adjusted using latitude, longitude, and depth sliders. Additionally, an Opacity Control slider is available to adjust the opacity of the model extent display, where 0 represents full transparency and 1 represents full opacity. This provides flexibility in visualizing underlying features.
• Earthquakes Visualization: The yellow dots on the map represent earthquakes with a magnitude greater than 4 that have occurred within the CRESCENT study area since 1970. The size of each yellow dot is proportional to the earthquake's magnitude, with larger dots indicating stronger earthquakes. This earthquake data is sourced from the ANSS Comprehensive Earthquake Catalog (ComCat), which compiles seismic events from various global and regional networks. The data is obtained through the USGS FDSN Event Service, ensuring up-to-date and accurate information on seismic activity. For more details on ComCat, visit ANSS ComCat, and for querying seismic data, visit the USGS FDSN Event Service.
• Imagery Layer: The imagery layer option (when checked) displays an imagery layer available through Cesium, offering detailed and reliable backgrounds for the visualization of geological and seismological data. Users may select different imagery layers using the imagery selection tool located at the top right of the interface.
• Terrain Occlusion Checkbox: Since imagery layers displayed on the map (when selected) are not transparent, the Terrain Occlusion checkbox is added to unhide the data displayed on the map. Enabling this feature helps to understand the spatial relationships between the terrain and the subsurface models.
• Feature Toggles: The interface includes checkboxes that allow users to turn on and off various features displayed on the map. This includes toggling the visibility of fault traces, earthquake data, and other model elements, providing flexibility in data visualization and analysis.
• Center View Button: The Center View button allows users to quickly center the map view on the CRESCENT study area or other areas of interest, making navigation easier and more efficient.
• Home View Button: The Home View button resets the map view to its initial default settings, providing a convenient way to return to the original perspective and overview of the map.
• Sync to Form Button: The sync to form button allows you to transfer your CVM selections to the form on the left. This allows you to set other data extraction parameters and extract the data. The maroon color on the sync button label indicates unsynced CVM changes on the map.
• Distance Measuring Tool: The distance measuring tool, located under the map legend and can be activated by checking the Measure Distance checkbox. This tool allows users to click on the map to select two points and measure the distance between them. When the first point is clicked, a point is placed at that location, and the second click places the second point. After both points are selected, a line is drawn connecting them, and the distance between the points is calculated and displayed. The distance is shown in kilometers in a designated display area. If more points are clicked after the second point, the previous line and markers are cleared, and the process starts over. This tool is designed to provide quick and easy measurement of distances between two locations on the map, with visual feedback through markers and lines. Additionally, the user can reset the tool by using a checkbox, which will clear the markers and distance line for a new measurement.

You can start by either directly changing the form parameters or setting the map parameters. To extract a sub-volume of a CVM, starting from the map's control panel, follow these steps:

First, on the map's control panel:

1. Show/Hide Controls: Use this button to display or hide the map controls.
2. Select a Model: Choose a model from the model list on the map's control panel.
3. Set the Volume Edges: Adjust the latitude and longitude coordinate sliders and the depth sliders to set edges of the desired sub-volume. The outline of the study area and the model's coverage area are shown in cyan for reference, and the selected sub-volume is shown in blue.
4. Select Model Variable(s): Select the model variable(s) to extract.
5. Sync Selections: Use the "Sync to Form" button to transfer your selections to the form on the left. This allows you to set other extraction parameters on the form and extract the data.

Next, on the form's control panel:

1. Download the model's netCDF file Use the download link under the 🔒 settings: checkbox to download the model's netCDF file.

2. Set the Data Parameters: Choose your preferred interpolation method and other processing parameters.
3. Select the Output Format: Select the output format from the supported formats for data extraction.
4. Download the Data: Click the "Download" button to download the extracted data.

Additional Parameters

Alternatively, you may set your parameters directly on the form and then use the "Sync to Map" button to send the information to the map and observe/adjust the selection coverage.