Fuzzy Deterministic Seismic Hazard Analysis (FDSHA)

This project is a C++ implementation of a Fuzzy Logic Expert System created for the CSci 141 - Intelligent Systems course.

About The Project

Fuzzy Deterministic Seismic Hazard Analysis (FDSHA) is a method that uses human-like, IF-THEN rules and fuzzy logic to calculate the Peak Ground Acceleration (PGA) at a site.

Instead of relying on complex, rigid formulas, the program takes general, descriptive information about a fault's magnitude, its distance to a site, and its type to calculate a precise measure of ground shaking (PGA).

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How It Works

The system uses a fuzzy logic engine to process inputs and determine the final hazard level.

Input Variables

The program accepts three numerical (crisp) inputs from the user.

• Maximum Magnitude (Mmax): The earthquake's magnitude on the Richter Scale (e.g., 4.5 to 8.5)
• Source-to-Site Distance (R): The distance from the fault in kilometers (e.g., 0 to 200)
• Fault Type (F): A normalized index representing the fault type (e.g., Normal ≈ -0.08, Thrust ≈ 0.08)

Output Variable

Based on the inputs and its rule base, the system calculates one output.

• Peak Ground Acceleration (PGA): The final measure of the seismic hazard, expressed in units of g (acceleration of gravity)

The program flow involves fuzzification (converting numbers to fuzzy terms), inference (applying rules), aggregation (combining results), and defuzzification (converting the fuzzy result back to a number).

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Getting Started

To get a local copy up and running, follow these simple steps.

Prerequisites

You will need a C++ compiler, such as g++.

Installation & Running

1. Clone the repo:

   git clone [https://github.com/Shinkrbs/fdsha.git](https://github.com/Shinkrbs/fdsha.git)

2. Navigate into the project directory:

   cd fdsha

3. Compile the source code (replace main.cpp with your file's name):

   g++ main.cpp -o fdsha_final

4. Run the program:

   ./fdsha_final

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Usage

Once running, the program will prompt you to enter the three input values.

For example, using the data from the "Low Hazard" test case.

Input:

Enter Maximum Magnitude (Mmax, typically 4.5 to 8.5): 5

Enter Source-to-Site Distance (R, in km, typically 0 to 200): 180

Enter Fault Type Index (F, e.g., Thrust: 0.08, Normal: -0.08): -0.09

Output:

--- ANALYSIS RESULT ---

Inputs Used:

Mmax (Magnitude): 5

R (Distance):     180 km

F (Fault Index):  -0.09

Calculated Peak Ground Acceleration (PGA): 0.0544111 g

Final Hazard Verdict: Negligible (Very Low Hazard)

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Reference

This work is based on the methods described in the following paper:

• Afsari, N., Abdipour, M. S., & Taghizadeh-Farahmand, F. (2022). Seismic hazard analysis from deterministic method using fuzzy logic in Anzali Port. Earth Science Informatics, 15(2), 793-806.