Earthquake 2025

The program

Earthquake 2025 is the desktop application for earthquake_2025, the program by Dr. Mario Galindo Queralt to generate artificial earthquakes. It creates accelerograms with superior spectral compatibility for structural time-history analysis, linear and nonlinear, even for structures with seismic isolation or energy dissipation.

Seismic codes define the action through a response spectrum, but time-history analysis needs an acceleration record. The program bridges both worlds, and it is distributed free of charge under the MIT license, together with its monograph.

More than 30 years of development

The method was born in the author's doctoral work at the Polytechnic University of Catalonia (1993), on the seismic analysis of concrete dams. In 1994 he wrote the chapter on spectrum-compatible artificial accelerograms in the CIMNE monograph Definición de la acción sísmica. The program has versions from 1992, 2005, 2022 and 2025, and its solver is deliberately kept in Fortran 77 for compatibility with the finite element community.

A two-phase hybrid method

• Phase 1, frequency domain: synthesizes signals as the sum of thousands of random-phase sine waves, modulated by an intensity envelope, and fits their spectral density until it approximates the target spectrum. Several candidates are generated and the best one is chosen.
• Phase 2, time domain: refines the best candidate with corrective wavelets until it reaches a "super-compatible" match with the spectrum.
• Baseline correction: final ground velocity and displacement are zero, as a physically consistent record requires.

The result follows the target spectrum with typical differences of just 1%, for one or several damping ratios at once, along with its intensity parameters: PGA, PGV, PGD, Arias intensity, CAV, Housner intensity, D5-95 significant duration and Husid plot.

The whole program, no command line

• Guided input editor, with the unit and exact monograph name of every parameter, validation as you type and live preview of the spectrum and envelope.
• Help linked to the monograph: each parameter has a "?" button that opens the book right at that parameter.
• Code spectrum wizard for ASCE 7, Eurocode 8, NBCC, BSL, NCh433, CFE-MDOC, NTE E.030 and NBDS-2023 (Bolivia).
• One folder per run with a PDF report, Excel workbook, charts and CSV tables, plus run comparison with its own report.
• Eleven ready-to-use examples and a bilingual English and Spanish interface.

Verified results

The application reproduces the results published in the monograph exactly: the chapter 5 examples and the appendix C case study give the same values, digit by digit. Every example is checked the same way before each release.

In our projects

It is the same method we used for the verification of the El Dorial Building, where the tower model was subjected to 16 artificial earthquakes compatible with the design spectrum provided by the Embassy of Canada.