Gravity Studio — 3D Geophysics Inversion & Forward Modeling Workstation

Created: August 2026 · Current Release: v2.1.0
Live Production App: gravity-studio.yufajjiru.work
GitHub Repository: github.com/luthfiyufajjiru/gravity-studio
Powered by: Terraversi

An integrated, browser-based geophysics workstation connecting field data acquisition, physical corrections, potential-field calculus, and 3D subsurface voxel forward modeling into a unified computational pipeline.

[!NOTE] Ecosystem Note: Looking for a lightweight, focused tool specifically for extracting global satellite altimetry and seafloor bathymetry grids without 3D forward modeling? Explore TOPEX Interactive (topex-interactive.yufajjiru.work).

Interactive 3D Voxel Forward Modeler with configurable grid geometry, lithology density palette, and real-time synthetic gravity response:

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The Geophysical Workflow

Traditional potential-field geophysics often isolates data reduction, regional filtering, derivative edge detection, and forward modeling across disparate desktop utilities. Gravity Studio bridges these steps into an end-to-end web workbench:

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Key Workspaces & Capabilities

1. Multi-Source Survey Ingestion & QC

• Ground & Airborne Land Surveys: Ingests raw tabular gravity readings (CSV, TSV, whitespace-delimited, and Excel .xlsx / .xyz) with automatic coordinate detection, latitude/longitude conversion, station elevation mapping, and interactive spreadsheet filtering.
• Satellite Altimetry Extraction: Ingests global marine and coastal gravity anomaly grids snapped to canonical $0.5^\circ \times 0.5^\circ$ discrete tiles with edge-cached streaming and zero-meridian wrap.

2. Four-Phase Inversion & Reduction Engine

• Phase 1: Data Gather & Quality Control: Soundings spreadsheet with real-time column sorting, spatial coordinate filtering, and multi-format GIS export.
• Phase 2: Complete Bouguer Reduction:
  • Continental ($h \ge 0$) and Marine ($h < 0$) Bullard-A reduction: $\text{BA} = \text{FAA} - 2\pi G (\rho_c - \rho_w) h + \text{TC}$
  • 3D Hammer / Hayford-Bowie Terrain Correction: Dynamic search radius ($5\text{–}35\text{ km}$) compensating for topography undulation and marine trenches.
  • Parasnis & Nettleton Linear Regression: Computes empirical crustal density $\rho_{\text{reg}}$ from the sounding cloud slope ($\Delta g_{\text{FAA}} = m \cdot h + c \implies \rho_{\text{reg}} = \frac{m}{2\pi G}$).
• Phase 3: Regional-Residual Field Separation:
  • Gaussian low-pass spatial filters (custom cutoff radius $10\text{–}150\text{ km}$).
  • Griffin (1949) moving-average boxcar ring filters.
  • 1st-order planar and 2nd-order paraboloid polynomial trend surface fitting to isolate deep Moho trends from shallow structural anomalies.
• Phase 4: 2D Potential Field Calculus & Structural Fault Delineation:
  • Tri-Map Synchronized Viewports: Simultaneous rasterization of Topography/Bathymetry, Free-Air Gravity Anomaly, and Complete Bouguer / Residual Anomaly with Bicubic Spline, Thin-Plate Spline, Bilinear, and IDW interpolation.
  • First Horizontal Derivative (FHD): Traces lateral density boundary contacts and fault inflections.
  • Second Vertical Derivative (SVD via Laplace's Equation): $\nabla^2 g = 0 \implies \frac{\partial^2 g}{\partial z^2} = -\left(\frac{\partial^2 g}{\partial x^2} + \frac{\partial^2 g}{\partial y^2}\right)$ Sharpens shallow basement edges and highlights zero-crossing fault boundaries.
  • Tilt Derivative (TDR): Automatic Gain Control (AGC) phase angle filter ($\theta = \tan^{-1}[\text{VDR}/\text{THDR}]$) equalizing amplitude decay across varying burial depths.
  • Elkins (1951) Fault Classification: Automated structural analysis classifying normal, reverse/thrust, and strike-slip fault steps from SVD dipole ratios.

Tri-Map Potential Field analysis viewport over a land gravity survey showing regional filtering and transect line profile:

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3. Interactive 3D Voxel Forward Modeler

• WebGL / Three.js 3D Sandbox: Interactive spatial grid with configurable physical bounds (area $X \times Z$, resolution, maximum topography height $Y > 0$, and subsurface depth $Y \le 0$).
• Lithology Density Library: Paint and sculpt voxels using standard rock and fluid densities:
  • Air ($0.00\text{ g/cm}^3$)
  • Water ($1.03\text{ g/cm}^3$)
  • Alluvium ($1.80\text{ g/cm}^3$)
  • Sediment ($2.20\text{ g/cm}^3$)
  • Host Crust Baseline ($2.67\text{ g/cm}^3$)
  • Granite ($2.70\text{ g/cm}^3$)
  • Basalt ($2.95\text{ g/cm}^3$)
  • Gabbro ($3.10\text{ g/cm}^3$)
  • Massive Sulfide Ore ($4.20\text{ g/cm}^3$)
• Real-Time Synthetic Gravity Physics: Background Web Worker evaluates gravitational attraction across all active voxels using analytical rectangular prism integration (Nagy 1966; Plouff 1976), plotting the computed $\Delta g$ (mGal) profile instantaneously as geometry is modified.

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4. Advanced Analysis & Joint Correlation

• Colocated Observation-to-Model Matching: Automatically pairs 2D gridded inversion soundings with colocated 3D forward synthetic responses.
• Observed vs. Calculated Cross-Plot: Visualizes observation alignment along the ideal $1:1$ diagonal.
• Statistical Quality Metrics: Evaluates Pearson correlation coefficient ($R^2$) and Root-Mean-Square (RMS) misfit error with automated geological tuning recommendations.

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5. Projects Hub & Preloaded Benchmarks

• Volcanic Caldera Magma Chamber: Collapsed summit caldera with low-density subterranean magma chamber ($\Delta\rho = -0.47\text{ g/cm}^3$, 121 sounding points, 81 voxels).
• Dense Mineral Pluton / Massive Sulfide: Deep high-density intrusive body ($\Delta\rho = +1.53\text{ g/cm}^3$, 27 voxels) producing a sharp SVD peak.
• Fault-Bounded Graben Rift Basin: Asymmetric extensional graben with sediment infill ($\Delta\rho = -0.67\text{ g/cm}^3$, 1,000 voxels) demonstrating steep FHD fault contact delineation.
• Subsurface Halite Salt Diapir: Buoyant salt plume ($2.15\text{ g/cm}^3$, 121 sounding points, 81 voxels) piercing dense carbonate overburden.
• Workspace Session State: Session persistence with unsaved-changes guard, Gravity Studio .json project file import/export, and multi-format deliverable exports (Oasis Montaj .XYZ, Surfer .GRD, Geosoft .GXF, GeoTIFF, GeoJSON, composite publication plates).

Projects Hub featuring preloaded benchmarks and workspace state management:

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Technical Stack & Architecture

Layer	Technology
Frontend Framework	React 18, TypeScript, Vite, PWA (vite-plugin-pwa)
3D Graphics & Canvas	Three.js, WebGL 2.0, Custom GLSL Fragment Shaders
Mapping & Geospatial	Leaflet, Leaflet-Draw, Google Satellite / ESRI Ocean Layers
Background Computation	Web Workers (geophysics.worker.ts, forward3d.worker.ts)
Edge Backend	Cloudflare Workers, Hono, Cloudflare Cache API
State & Navigation	SPA Hash Router with URL stage synchronization (#/inversion?stage=bouguer)
Data & Deliverables	Oasis Montaj .XYZ, Surfer .GRD, Geosoft .GXF, GeoTIFF, GeoJSON, CSV, High-DPI PNG Plates
Hosting & Deployment	Cloudflare Workers (Custom Domain: gravity-studio.yufajjiru.work)

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Project Links

• Live Production App: https://gravity-studio.yufajjiru.work
• Source Code Repository: https://github.com/luthfiyufajjiru/gravity-studio
• Companion Satellite Altimetry Tool: TOPEX Interactive · Portfolio Overview