These sliders control parameters for both models simultaneously.
These models illustrate **Elastic Rebound Theory**. The ground slowly deforms (stores elastic strain) during the interseismic period, which is then suddenly released (coseismic displacement) during an earthquake.
This plot shows the *rate* of ground motion (velocity) during the long period *between* earthquakes, based on the 2D `arctan` model.
Formula Used: v(x) = (s / π) * arctan(x / d)
v(x): Velocity at distance y from the fault.s: Long-term slip rate (e.g., mm/yr).d: Locking depth of the fault.x: Perpendicular distance from the fault.Key Observation: The ground is "locked" at the fault (velocity = 0), while the ground far away moves at the full plate velocity. A deeper locking depth (larger d) creates a wider, more gradual zone of strain accumulation.
Real-World Measurement: Measured using **GPS** stations over many years.
This plot shows the *permanent* ground displacement *during* an earthquake, based on a model that shows 1/x^2 decay.
Formula Used: u(x) = s / (1 + (x / d)²)
u(x): Displacement at distance x from the fault.s: Slip on the fault at x=0.d: A term related to the fault's depth/width.x: Distance from the fault.Note: This simple function is an approximation of complex 3D models (like Okada), but it correctly shows that displacement is **maximum at the fault** and **decays rapidly** (like 1/x^2 at large distances).
Real-World Measurement: Measured using **GPS** and **InSAR** (satellite radar) immediately after an earthquake.