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.

PGV (cm/s)

Required number in cm/s. Peak ground velocity.

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

Japan Meteorological Agency instrumental intensity from PGV (cm/s): I_JMA = 2.68·log₁₀(PGV) + 2.29 (approx). Inputs are interpreted exactly in the displayed units and the calculation returns the following fields without presentation rounding.

I_JMA

Returned number. JMA instrumental intensity (rounded to 0.5).

• 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.
• PGV must be at least 0.
• 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.

• ShakeMap Instrument Intensity PGV Converter

  Convert PGV to instrumental intensity with the Wald et al. (1999) ShakeMap relation MMI = 3.51·log₁₀(PGV in cm/s) + 2.35, clamped to the displayed MMI range 1–10.

• Kovesligethy Intensity Decay Isoseismal Calculator

  Kövesligethy isoseismal radius: I(r) = I₀ − 3·log₁₀(√(r²+h²)/h), inverted for a target intensity.

• Mercalli vs JMA Crosswalk Lookup

  Crosswalk between JMA instrumental scale and equivalent MMI range.