TRIGRS

Automates TRIGRS rainfall-infiltration and slope-stability simulations from grid preparation to output parsing.

155|6|Updated Mar 31, 2026
One-click install
npx skills add https://github.com/lzwei196/KISS-Knowledge-Infrastructure-for-Scientific-Simulation --skill trigrs-lzwei196
Or copy as Structured Prompt for Agent
Please help me install this Agent Skill.
Skill: TRIGRS
Source: https://github.com/lzwei196/KISS-Knowledge-Infrastructure-for-Scientific-Simulation/tree/main/models/TRIGRS
Command: npx skills add https://github.com/lzwei196/KISS-Knowledge-Infrastructure-for-Scientific-Simulation --skill trigrs-lzwei196

SYSTEM DOCUMENTATION & REQUIREMENTS

💡 This Skill requires numpy, and includes scripts (resource) and references (resource) components.

What problem does it solve? Running the USGS TRIGRS Fortran model for rainfall-induced shallow landslide analysis requires manual GIS grid preparation, error-prone unit conversions, and command-line execution where silent unit mistakes produce plausible but wrong factor-of-safety results. ## Core Features & Use Cases - Validated Python pipeline: Five tools convert rainfall forcing and soil properties into TRIGRS inputs, generate the tr_in.txt initialization file, run the compiled trg binary with TopoIndex, and parse factor-of-safety grids to CSV. - Unit-trap defense: Explicit conversion tables and physical-bounds validation catch the silent 1000x and 3.6-million-fold unit errors (Pa vs kPa, m/s vs mm/hr) that dominate TRIGRS failures. - Diagnostic recovery: Eighteen symptom-diagnosis-remedy triplets map known failure modes to fixes, plus a preflight check that verifies the binary, environment, and data before execution. - Use Case: Given a DEM, slope grid, soil texture table, and a rainfall time series for a 48-hour storm, generate all TRIGRS inputs, run the model, and obtain a minimum factor-of-safety grid identifying cells where Fs drops below 1. ## Quick Start Run the preflight check in this directory, then ask the agent to prepare TRIGRS inputs from your DEM, soil, and rainfall data and execute the model to produce the minimum factor-of-safety grid.

Frequently Asked Questions about TRIGRS

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I run a TRIGRS landslide susceptibility simulation?

Prepare congruent ESRI ASCII grids (DEM, slope, zones, soil depth, water table), convert rainfall to m/s intensity grids, generate tr_in.txt, then run the compiled trg binary. The run_trigrs.py tool wraps compilation, TopoIndex, execution, and output validation.

What units does TRIGRS expect for rainfall and soil parameters?

TRIGRS expects rainfall intensity in m/s, time in seconds, cohesion in Pa, unit weights in N/m^3, K-sat in m/s, and slope in degrees. Entering mm/hr rainfall or kPa cohesion causes silent errors with results wrong by factors of thousands or millions.

Why does my TRIGRS run show factor of safety below 1 everywhere?

This usually means rainfall intensity was entered in mm/hr instead of m/s, delivering 3.6 million times too much water and saturating all cells instantly. Check diagnostics/triplets.yaml for the matching unit-conversion symptom and remedy.

Can TRIGRS model deep-seated or rotational landslides?

No. TRIGRS uses infinite-slope stability analysis with 1D vertical infiltration per cell, so it only predicts shallow planar failures. Deep-seated, rotational, and laterally coupled groundwater flow are outside its scope.

What is the difference between the saturated and unsaturated TRIGRS models?

The unsaturated model (Srivastava-Yeh) activates when Alpha is positive and theta-sat exceeds theta-res; a negative Alpha silently falls back to the saturated Iverson model. The mmax sign separately selects finite-depth versus infinite-depth basal boundaries.