hypoDD - A Program to Compute Double-Difference Hypocenter Locations - Open File Report 01-113

Sep 17, 2026

Preliminary USGS Open File Report 01-113 by Felix Waldhauser introduces hypoDD version 1.0-03/2001, a computational program for determining earthquake hypocenter locations using a double-difference approach. The report outlines the end-to-end workflow, including preprocessing with ph2dt, earthquake relocation with hypoDD, event clustering, selection criteria, and initialization and solution control. It further describes data weighting and re-weighting strategies, interprets hypoDD outputs, and provides error assessment methods, references, acknowledgements, and appendices detailing ph2dt and hypoDD installation, inputs, and outputs.

LanguageEnglish

CategoryResearch & Report

FormatPDF

Pages25

Reading Time1 h 3 min

AccessFree to download

Introduction and Overview

Data Preprocessing Using ph2dt

Earthquake Relocation Using hypoDD

Data Selection and Event Clustering

Initial Conditions and Solution Control

Data Weighting and Re-weighting

Analysis of hypoDD Output

Error Assessment

References

Acknowledgements

APPENDIX A. Reference for ph2dt

Description

Installation and Syntax

Input Files

Output Files

APPENDIX B. Reference for hypoDD

Description

Installation and Syntax

Input Files

Output Files

APPENDIX C. Utility Programs

hypoDD--A Program to Compute Double-Difference Hypocenter Locations (hypoDD version 1.0-03/2001) by Felix Waldhauser U.S. Geol. Survey 345 Middlefield Rd, MS977 Menlo Park, CA 94025 [felix@andreas.wr.usgs.gov](felix@andreas.wr.usgs.gov) [Open File Report 01-113](Open File Report 01-113) This report is preliminary and has not been reviewed for conformity with U.S. Geological Survey editorial standards or with the North American Stratigraphic Code. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Table of Contents Introduction and Overview ........................................................................................................................... 3 Data Preprocessing Using ph2dt................................................................................................................... 4 Earthquake Relocation Using hypoDD......................................................................................................... 7 Data Selection and Event Clustering....................................................................................................... 7 Initial Conditions and Solution Control .................................................................................................. 8 Data Weighting and Re-weighting ........................................................................................................ 10 Analysis of hypoDD Output ................................................................................................................... 12 Error Assessment ................................................................................................................................... 13 References................................................................................................................................................... 13 Acknowledgements..................................................................................................................................... 14 APPENDIX A. Reference for ph2dt ....................................................................................................... 15 A.1 Description..................................................................................................................................... 15 A.2 Installation and Syntax .................................................................................................................. 15 A.3 Input Files ...................................................................................................................................... 15 A.3.1 Control File (e.g. file ph2dt.inp) ............................................................................................ 15 A.3.2 Catalog (absolute) travel time data (e.g. file phase.dat) ....................................................... 16 A.3.3 Station location information (e.g. file station.dat) ................................................................. 17 A.4 Output Files ................................................................................................................................... 17 APPENDIX B. Reference for hypoDD................................................................................................... 17 B.1 Description ..................................................................................................................................... 17 B.2 Installation and Syntax................................................................................................................... 17 B.3 Input Files ...................................................................................................................................... 17 B.3.1 Control File (e.g. file hypoDD.inp) ....................................................................................... 17 B.3.2 C

FAQs

What problem does hypoDD solve in earthquake studies?

hypoDD is designed to compute earthquake hypocenter locations using a double-difference method, improving relocation based on differential information.

What are the main workflow stages described in the report?

The report covers data preprocessing with ph2dt, earthquake relocation using hypoDD, data selection and event clustering, then initialization, solution control, and weighting/re-weighting.

What information is provided about running ph2dt and hypoDD?

Appendix A and Appendix B provide references including descriptions, installation and syntax, and detailed input and output file specifications for ph2dt and hypoDD.

Sep 17, 2026

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