TS - Gauss (Mediterranean Basin)

1. Introduction

TS-Gauss is a web application designed for rapid tsunami simulations based on pre-computed Green's functions. The tool enables near-instantaneous calculations of tsunami waveforms and maximum wave amplitudes at specific locations along the Mediterranean coastline.

The application leverages the Gaussian Toolbox, which integrates advanced methodologies to produce accurate results for tsunami hazard analysis. You can download the full documentation of the Gaussian Toolbox here:

📄 Gaussian Toolbox Documentation (PDF)

Key Components

• Interactive Map:
  • A dynamic map interface powered by Leaflet, allowing users to explore, visualize, and interact with tsunami simulation results in real time.
• Points of Interest (POIs):
  • A total of 1107 POIs are strategically placed along the 50-meter isobath of the Mediterranean basin.
  • The POIs represent coastal locations where the linear shallow water approximation remains valid for tsunami propagation.
  • Results at these POIs are displayed dynamically on the map, including maximum wave amplitudes and waveform characteristics.
• Gaussian Tsunami Sources (GS):
  • Tsunami sources are modeled as Gaussian-shaped elementary sources uniformly distributed across the sea surface.
  • Each Gaussian source has a radius of approximately 4 km and is spaced evenly at intervals of ~4 arc minutes.
  • The tsunami waveforms at POIs are computed using a linear combination of pre-computed tsunami Green's functions, weighted by the initial sea surface deformation.

Wave Propagation Calculations

The tsunami wave propagation calculations rely on two primary methods:

1. Pre-computed Green’s Functions:
   • Pre-calculated mareograms (tsunami time series) represent the propagation of tsunami waves from each Gaussian source to every POI.
2. Seabed Deformation:
   • The initial tsunami condition is derived from co-seismic seabed deformation, using different models depending on the fault type:
     • Okada’s model (1985) is applied for manual input and rectangular faults.
     • Nikkhoo & Walter’s method (2015) is used for triangular faults.

2. System Requirements

• Supported Browsers: Google Chrome, Mozilla Firefox, Safari, Microsoft Edge.
• Internet Connection: Required for accessing and using the application.

3. Accessing the Application

1. Open your preferred web browser.
2. Navigate to the application's URL: http://ts-gauss.rm.ingv.it/.
3. No login credentials are currently required.

4. Input Data

The tsunami scenario can be defined either by manually entering a few earthquake parameters or by uploading a dedicated input file.

4.1 Manual Input

Enter the following parameters manually in the provided input form:

• Magnitude: Earthquake magnitude (e.g., 7.5)
• Longitude/Latitude: Hypocenter coordinates (Longitude: -6° to 36°, Latitude: 30° to 46°). You can also set these values by clicking on the map using the button located at the top-right corner of the map, just below the zoom controls, marked with the icon.
• Depth: Hypocenter depth in kilometers (must be > 0)
• Strike: Strike angle in degrees (0–360)
• Dip: Dip angle in degrees (0–90)
• Rake: Rake angle in degrees (0–360)

In this case, a rectangular fault geometry and a homogeneous slip value are imposed by the code through specific earthquake scaling relations.

Figure 1: Interface for Manual Data Input

4.2 Upload File

Alternatively, you can upload an ASCII file containing one or more earthquake sources. Accepted file formats are .dat, .txt, .out, .csv.

The file must be formatted precisely according to the selected fault representation model:

• For a Rectangular Fault, each row must contain exactly 9 values; These values describe the center of the fault and its geometry.
• For a Triangular Fault, each row must contain exactly 11 values; These define the coordinates of the three corners of the triangle, along with its rake and slip.

Note: If the file is correctly formatted, the software will automatically detect the fault type based on the number of values in each row.

4.2.1 Rectangular Fault Elements

The earthquake scenario is described through one or more rectangular fault planes. The file (e.g., multiseg.dat) must have the following structure:

              LON_EPI  LAT_EPI  DEPTH_EPI(km)  L(km)  W(km)  STRIKE  DIP  RAKE  SLIP(m)
              184.056300  -28.638800  4.449000  10.000000  10.000000  201.000000  16.000000  69.175500  0.021300
              184.019200  -28.722800  4.449000  10.000000  10.000000  201.000000  16.000000  93.730800  0.050000
              ...
                

A header line like the one shown is optional.

4.2.2 Triangular Fault Elements

Alternatively, the earthquake scenario can be described using a mesh of triangular subfaults. The file must follow this structure:

              LON1 LAT1 DEPTH1(km) LON2 LAT2 DEPTH2(km) LON3 LAT3 DEPTH3(km) RAKE SLIP(m)
              60.113998 25.377488 6.497971 60.111129 25.283265 5.821749 60.252835 25.278935 5.888381 90.000000 0.000000
              61.246613 26.606740 22.712066 61.365629 26.632410 22.327012 61.227469 26.706145 24.540247 90.000000 0.000000
              ...
                

A header line is optional and will be automatically handled if present.

Important: The dropdown menu to select the fault representation type is no longer required, as detection is fully automatic.

Figure 2: Interface for Uploading Earthquake Scenario Files

5. Running the Calculation

5.1 Manual Input

1. Enter the required parameters into the Input Form.
2. Click the "Send Request" button.
3. The system calculates the results using pre-computed Green's functions. Calculation typically takes about one minute; we are continually optimizing this.
4. If errors occur, read the displayed message carefully. Contact technical support if the issue is unclear.

A summary table below displays previously entered data. You can click a row in this table to reload the map and revisit results. The application's memory is reset after 24 hours.

Figure 3: Summary Table of Previously Entered Manual Data

5.2 Upload File

1. Drag and drop your ASCII file into the upload box, or click "Select File" to browse your device.
2. You may deselect or change the file before submission if necessary.
3. Click "Send Request" to process the file. Results are shown at the same POIs as with manual input.

A summary table below the upload section lists previously submitted files including:

• File Name
• File Extension
• File Size

You can click a table row to reload previous calculation results. The application's memory is reset after 24 hours.

Figure 4: Summary Table of Previously Uploaded Files

6. Viewing Results

Results are visualized through an interactive map powered by Leaflet. Users can zoom in and out, click on Points of Interest (POIs) to display their names, latitude, longitude, and wave amplitude. Additionally, the map shows the epicenter of the seismic event.

When a point is selected on the map, the corresponding row in the results table is highlighted. Similarly, newly inserted data is automatically colored to ensure quick identification.

New! A toggle switch on the map allows users to visualize either:

• Offshore maximum wave amplitude, directly calculated at each POI,
• or the amplified coastal wave height computed using Green’s Law.

This feature helps to interpret the effective wave impact on coastal regions by approximating wave amplification during shoaling.

6.1 Interactive Color Legend

A color legend is displayed on the map, representing the maximum wave amplitude in meters. The legend uses a gradient scale, where different colors indicate increasing values of wave amplitude. The scale is defined as follows:

• Dark blue (low values, close to 0.0 m)
• Light blue → Green → Yellow (intermediate values, from 1.0 m to 2.0 m)
• Orange → Red → Dark Red (high values, reaching 3.0 m and above)

The legend is dynamically generated using Leaflet and positioned at the bottom of the map. It includes a linear gradient bar with tick markers and numeric labels to provide an intuitive reference for interpreting wave heights.

To improve map clarity, a toggle button is available to hide the legend when needed. Once hidden, a small floating button appears, allowing users to re-enable the legend with a single click. The hiding and showing actions include smooth animations for an intuitive experience.

Additionally, users can toggle between Offshore Wave Height and the amplified wave height calculated using Green’s Law. This switch updates both the displayed markers and color mapping, offering a more accurate coastal hazard visualization.

Figure 5: Interactive Map Interface

7. Downloading and Deleting Results

7.1 Downloading Results

The Download button provides two main categories of downloadable files:

• Map Files:
  • Map HTML: Generate an interactive HTML map.
  • Map PNG: Export the currently displayed map as a PNG image.
  • Map GMT: Generate the map using GMT code.
  • Map KML: Export a KML file compatible with Google Earth.
  • Map Points (GeoJSON): Download the GeoJSON file with map points.
• ASCII Files:
  • UZ Grid File (.grd): Download the UZ grid file in ASCII format.
  • Mareograms (.out): Download the mareograms output file.
  • SSHMax (.out): Download the SSHMax output file in ASCII format.

7.2 Additional Downloads Based on Input Method

Depending on the input method selected (Manual Input or Upload File), additional download options are provided:

• Manual Input:
  • Ruptgen Log (.log): Download the log file containing detailed output and logs generated by the Ruptgen command.
• Upload File:
  • Uploaded Input File: Download the original file that you previously uploaded for calculation.

Manual Input

File Upload

Figure 6: Side-by-side buttons for Manual Input and File Upload

7.3 Deleting Results

• Click the trash icon next to the download button.
• Confirm or cancel the deletion.

8. System Testing Phase

The TS-Gauss system is currently undergoing active testing and validation. During this phase, the following considerations apply:

• Data Visibility: All results are publicly accessible to users within the network for testing and demonstration purposes.
• Temporary Storage: Data generated by manual inputs or file uploads are retained for 24 hours. After this period, all data is automatically deleted to maintain system efficiency and privacy.

Your feedback during this testing phase is valuable to help us improve the system performance and user experience.

9. Recently Added Functionalities

To enhance user interaction and streamline the data input process, the following functionalities have recently been implemented:

• Interactive Coordinate Selection: A dedicated button within the interactive Leaflet map allows users to conveniently select coordinates by simply clicking on any location. The corresponding longitude and latitude values are automatically filled into the input fields, improving accuracy and efficiency in data entry.
• Wave Height Display Toggle: Users can now switch between two types of wave height representations directly from the interactive map:
  • Offshore Height: The original computed wave amplitude at the offshore Point of Interest (POI).
  • Green's Law Height: An estimation of coastal amplification based on Green’s Law, which simulates wave shoaling effects in shallow water.

  This toggle allows better visualization of tsunami impact near coastal areas. Switching modes will update both the map markers and amplitude values accordingly.



Offshore & Green's Law Height

• Color Legend Visibility Toggle: A new button allows users to hide or show the color legend that represents maximum wave amplitude. This legend is located at the bottom of the map and can be temporarily hidden to provide a clearer view of data points.

  When hidden, a floating button appears, enabling users to bring the legend back at any time. Transitions are animated for a smoother user experience.

10. Experimental Nature of the Service (Important Disclaimer)

11. Troubleshooting

• Page Not Loading:
  • Ensure your internet connection is stable.
  • Clear your browser's cache and cookies, then try again.
  • If issues persist, contact technical support.
• Input Errors:
  • Verify all entered parameters are within specified ranges.
  • Double-check the format and completeness of the uploaded file.
  • Review the error message displayed and adjust accordingly.
• Results Not Displaying:
  • Refresh the page or reload your previous submission via the summary table.
  • If problems continue, please contact support for further assistance.

12. FAQ

• Q: How do I export the map?
  • A: Use the "Download" button, which offers various formats such as HTML, PNG, GMT, KML, and GeoJSON.
• Q: How long is data stored in the system?
  • A: Data from manual inputs and uploaded files are stored for 24 hours.
• Q: Can I review previous calculations?
  • A: Yes. Click on the row in the summary table to reload previous results and maps.
• Q: What should I do if an error message is unclear?
  • A: Contact the support team with details of the issue for assistance.

13. Contact and Support

• Support Email: ts-gauss.feedback@ingv.it
• Feedback Form: JotForm Feedback

14. Credits

The TS-Gauss project has been developed by:

• Ludovico Vitiello - ludovico.vitiello@ingv.it
• Andrey Babeyko - babeyko@gfz-postdam.de
• Sergio Bruni - sergio.bruni@ingv.it
• Roberto Vallone - roberto.vallone@ingv.it
• Fabrizio Romano - fabrizio.romano@ingv.it
• Roberto Tonini - roberto.tonini@ingv.it
• Stefano Lorito - stefano.lorito@ingv.it

All team members are affiliated with the Istituto Nazionale di Geofisica e Vulcanologia (INGV), Rome, Italy, except for Andrey Babeyko, who is affiliated with the German Research Center for Geosciences (GFZ), Potsdam, Germany.

Scientific Reference: The methodology and framework underlying the TS-Gauss system were presented at the EGU General Assembly 2025. You can consult the abstract titled “TS-GAUSS, a web application for rapid estimation of tsunami impact based on pre-calculated simulations in the Mediterranean Sea” at the following link:
https://meetingorganizer.copernicus.org/EGU25/EGU25-19547.html .