Use this geological calculation for a transparent first-pass interpretation of measured rock, soil, fluid, well, stratigraphic, isotopic, geophysical, or seismic data under an explicitly selected model.

Vp1

P-wave velocity of the upper layer in meters per second.

rho1

Bulk density of the upper layer in kilograms per cubic meter.

Vp2

P-wave velocity of the lower layer in meters per second.

rho2

Bulk density of the lower layer in kilograms per cubic meter.

Normal-incidence P-wave reflection coefficient R = (Z2 - Z1) / (Z2 + Z1) from layer velocities in meters per second and bulk densities in kilograms per cubic meter, where Z is acoustic impedance. The tool evaluates the supplied inputs together and returns the named outputs below; it does not infer omitted operating conditions or change the units shown.^[1]

R

Normal-incidence reflection coefficient, dimensionless.

Z1

Acoustic impedance of the upper layer in pascal seconds per meter.

Z2

Acoustic impedance of the lower layer in pascal seconds per meter.

• Seismic magnitudes, moments, travel times, velocities, resolution, and energy depend on instrument correction, Earth model, phase picking, geometry, attenuation, radiation pattern, bandwidth, and calibration range. Magnitude scales are not universally interchangeable.
• Use finite inputs in the displayed units and preserve more precision than the final presentation requires. Independently verify safety-critical, financial, compliance, or production decisions.

Compare independent measurements and models, retain units and analytical metadata, propagate uncertainty, and validate interpretations against logs, cores, maps, laboratory data, or field observations.

• Seismic Acoustic Impedance Calculator

  Acoustic impedance Z = rho Vp from P-wave velocity in meters per second and bulk density in kilograms per cubic meter, returned in pascal seconds per meter.

• Seismic Rms Velocity Calculator

  Layer-root-mean-square velocity Vrms^2 = sum(Vi^2 ti) / sum(ti) from per-layer velocities in meters per second and one-way interval travel times in seconds.

• Well Log Porosity Density Calculator

  Density-log porosity phi_D = (rho_ma - rho_b) / (rho_ma - rho_f) from bulk, matrix and pore-fluid densities in kilograms per cubic meter; the standard formation-density porosity relation.