Use this seismology calculation to reproduce a stated convention, screen observations, or compare scenarios whose units, coordinate conventions, catalog selection, and model assumptions are known.

az

Required list. Station azimuths in degrees (0–360).

The cited overview of Seismometer supplies background for the terminology and domain context used by this tool.^[1]

Largest azimuthal gap between consecutive stations around an epicenter. Inputs are interpreted exactly in the displayed units and the calculation returns the following fields without presentation rounding.

Gap (°)

Returned number in °. Largest azimuthal gap.

Quality

Returned string. Coverage quality rating.

• Earth structure, source geometry, path effects, site response, instrument response, catalog completeness, uncertainty, and the fitted range can dominate the accuracy of simplified seismic calculations.
• Use finite inputs in the displayed units, preserve source measurements and assumptions, and independently verify consequential decisions.

For analysis or hazard decisions, retain uncertainty and provenance and compare the result with waveform processing, calibrated regional models, and guidance from qualified seismologists or the responsible agency.

• Azimuthal Hole Location Bias Warning Checker

  Warn when the station azimuthal gap is wide enough to push hypocentres systematically into the gap.

• Bath Law Largest Aftershock Gap Note Lookup

  Båth's law: the largest aftershock sits about 1.2 magnitude units below its mainshock.

• Network Detection Threshold Coverage Calculator

  Illustrative magnitude-of-completeness screening relation M_min ≈ 1.5 + log₁₀(r/km) using a detection radius of 1.5 times station spacing; it is not a calibrated network threshold.