Building a Tool to Predict Damage Patterns from Meteoroid Airbursts

Abstract

Most meteoroids do not reach the ground fully intact, they explode mid-air. These airbursts produce a shockwave that propagates to the ground and creates a damage pattern, typically in the shape of a butterfly for oblique entry angles and more oval or circular for steep impacts. The shape varies due to the height of the airburst, impact angle, and impact velocity. My goal is to create a web-based airburst simulator. The first step is determining the relationship between the airburst parameters and the shape of the contours representing the area affected by the meteoroid. This browser would include a GUI interface with sliders or knobs to control the bolide’s size, entry angle, speed, and height of burst. The output will be a contour map of damage at Earth’s surface at locations specified from a risk corridor, such as those calculated by JPL CNEOS for potentially hazardous objects, output as a Google Earth KML file or similar. So far, I have represented the contours using a Fourier series. The next step is to find a relationship between the parameters and the Fourier series.

Research Period
June 2025 – August 2025

Research Guidance
Guidance under Dr. Catherine Plesko, Los Alamos National Laboratory (LANL), New Mexico

Hypothesis
The shape of a meteor airburst’s ground damage pattern can be described using a simple mathematical model. By knowing the meteor’s burst height, entry angle, and speed, we can predict its “butterfly” or oval impact shape without needing a full simulation.

Motivation
Planetary defense is one of the few areas of space science that directly affects human safety. People care deeply about it, which makes it an ideal topic to communicate to the public. Working on airburst modeling has shown me how much precision and complexity go into predicting impacts, and how important it is to make that science understandable. This project helps me build the scientific foundation I need to create clear, engaging visuals that help people connect with the science behind asteroid threats.

Problem Breakdown

Manual Shape Approximation: I began by recreating the butterfly-shaped ground damage pattern using a piecewise polar function in MATLAB. By adjusting each segment through trial and error, I learned how entry angle and symmetry affect the overall geometry.
Translation to Python and Geographic Testing: After verifying the shape, I converted the equations to Cartesian coordinates in Python and exported the contour as a KML file. This allowed me to visualize the pattern on real geography in Google Earth and confirm realistic scale and orientation.
Contour Extraction from Real Event Data: I used the findContours function in Python to detect the blast outline from the 1908 Tunguska treefall map. The automatic extraction included extra edges and text, so I manually cleaned the result to isolate the continuous boundary representing ground damage.
Fourier Representation of the Damage Pattern: I applied a Fast Fourier Transform (FFT) to the cleaned contour to calculate Fourier coefficients that mathematically describe the butterfly geometry. This provided a consistent way to compare shapes and test how the pattern might change for different entry conditions.
GUI Prototype Development: Although I was not yet able to find a direct quantitative relationship between the input parameters (burst height, angle, and speed) and the Fourier coefficients, I developed a working browser interface. The GUI uses placeholder images and adjustable sliders to demonstrate how users will eventually be able to explore airburst scenarios interactively.

Quantifiable Outcomes
1. Automated Contour Extraction: The findContours workflow in Python was able to detect and extract the main damage boundary from the Tunguska treefall map. Manual cleanup created a continuous similar contour to the original suitable for Fourier analysis.
2. Fourier Representation of Damage Contours: I successfully generated an equation using Fourier fit with 20 terms that mathematically describe the butterfly-shaped ground damage pattern.
3. KML Visualization: The resulting contours were converted to KML format and overlaid on real geography in Google Earth, confirming realistic scale and demonstrating how the model output could be visualized in a geographic context.
4. Interactive GUI Prototype: A functioning browser-based interface was created with adjustable sliders and placeholder visuals to simulate the tool’s final design. Although the relationship between the parameters of the impactor and shape of the ground damage is still under study, the framework for user interaction and visualization is already established.

Skills Acquired

Fourier Analysis and Geometry Fitting: Learned how to represent complex, irregular shapes using Fourier series and interpret how different terms correspond to features of the physical system.
Geospatial Visualization: Developed skills in exporting simulation results to KML format and visualizing them in Google Earth, connecting mathematical results to real geographic scales.
Interface Design: Built a prototype browser GUI with interactive sliders and visual feedback, strengthening my understanding of how to design tools that communicate scientific models to users.

Key Learnings

Scalar estimates are often sufficient for early-stage assessment: This project showed me that approximate, low-order representations can provide useful insight into impact outcomes, especially for rapid evaluation and communication, even when detailed simulations are not available.
Shape alone is easier to model than physics-to-shape relationships: While I was able to represent butterfly-shaped damage patterns accurately, finding a direct, closed-form relationship between physical input parameters and contour geometry is significantly more challenging and requires much broader datasets.
Planetary defense benefits from clear, accessible models: Because airburst hazards directly affect people on the ground, even simplified tools can play an important role in helping scientists, decision-makers, and the public understand potential risks and response scenarios.
Tool design and science development can proceed in parallel: Even without a finalized physical scaling law, building the GUI early clarified how users would interact with the model and what scientific relationships are most important to prioritize next.

Graphs and Visualization

Contours from 3D simulations showing blast patterns for asteroid airbursts at various entry angles. Adapted from Boslough et al. (2025), these patterns help in understanding how entry angle affects the shape of the damaged region.

This map shows observed treefall directions and blast extent from the 1908 airburst. It was originally published by K.P. Florenskii (1963) and reproduced in later works, including Vasilyev et al. (2013).

These are the contours detected by Python from the Tunguska damage map.

The main line is the longest contour that was detected.