AfterShock Calculator

A web application for generating earthquake aftershock forecasts based on the Omori-Utsu law and Poisson distribution. Built for Earth Sciences New Zealand (ESNZ).

Features

• GeoNet Integration: Fetch earthquake data directly from the GeoNet API using quake IDs
• Multiple Seismicity Models: Pre-configured parameters for different tectonic settings:
  • NZ Generic (New Zealand active continental region)
  • Subduction Zone (Hikurangi/Puysegur)
  • California/ACR (Reasenberg & Jones, 1989)
  • Stable Continental Region (Page et al., 2016)
  • Custom user-defined parameters
• Configurable Forecasts: Adjustable forecast durations and magnitude thresholds
• Statistical Output: Expected aftershock counts, 95% confidence intervals, and probability of occurrence
• CSV Export: Download forecast results for further analysis

Tech Stack

• Framework: Next.js 14 (App Router)
• Language: TypeScript
• Styling: Tailwind CSS v4
• Font: Inter (Google Fonts)

Project Structure

src/
├── app/
│   ├── layout.tsx      # Root layout with metadata
│   ├── page.tsx        # Main calculator page
│   └── globals.css     # Global styles
├── components/
│   ├── QuakeInput.tsx      # Earthquake ID input and data fetching
│   ├── Parameters.tsx      # Magnitude and duration configuration
│   ├── ModelSelector.tsx   # Seismicity model selection
│   └── ResultsTable.tsx    # Forecast results display
├── lib/
│   ├── api.ts          # GeoNet API client
│   └── calculations.ts # Aftershock calculation logic (Omori-Utsu)
└── types/
    └── index.ts        # TypeScript type definitions and model presets

Getting Started

Prerequisites

• Node.js >= 18.17.0

Installation

npm install

Development

npm run dev

Open http://localhost:3000 in your browser.

Build

npm run build
npm start

Scientific References

• Reasenberg, P.A. & Jones, L.M. (1989, 1994): California aftershock parameters
• Page, M. et al. (2016): Global tectonic regime parameters
• Hardebeck, J.L. et al. (2018): Updated California parameters