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.

u_s (m)

Required number in m. Average coseismic slip.

δ (°)

Required number in °. Fault dip.

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

First-order seafloor vertical offset from dip-slip on a fault: u ≈ slip·sin(dip). Inputs are interpreted exactly in the displayed units and the calculation returns the following fields without presentation rounding.

u_z (m)

Returned number in m. Vertical seafloor offset.

η

Returned number. Geometric vertical-to-total slip ratio, sin(dip).

• 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.
• u_s must be at least 0.
• δ must be at least 0.
• δ must be no greater than 90.
• 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.

• Dip-Slip Seismic Moment and Average Dislocation Estimate

  Seismic moment and average dislocation estimate for a dip-slip rupture: geodetic moment M₀ = μ·A·ū plus a heuristic vertical offset scale; this tool does NOT solve the Okada (1992) elastic half-space displacement field.

• Strain Drop Slip Over Length Stress Drop

  First-order stress drop from the strain-drop picture: Δσ ≈ μ·(D/L).

• Tsunami Runup Empirical Okal Synolakis Lookup

  First-order far-field tsunami runup scaling with magnitude and distance (heuristic exponents).