Seismic Wave Propagation Simulator

Earthquake Location

Preset Epicenters

Station Location

Preset Stations

Station Latitude (°)

Station Longitude (°)

Earthquake Properties

Focal Depth (km)

Magnitude (Mw)

Wave Properties

P-Wave Speed (km/s)

S-Wave Speed (km/s)

Surface Wave Speed (km/s)

Simulation Controls

Simulation Speed

Recording Duration (min)

Auto (calculated)

Global Wave Propagation

Epicenter

Seismic Station

P-Wave

S-Wave

Surface Wave

T+00:00

Hover to see coordinates

Initializing Earth Model...

Seismogram Recording

Station: SEIS (41.90°, 12.50°)

±50 mm/s

+50 mm/s

+25 mm/s

0 mm/s

-25 mm/s

-50 mm/s

0:00 0:30 1:00 1:30 2:00 2:30 3:00

Generating Seismogram...

Earthquake Analysis

Epicenter

Station

Focal Depth

Magnitude

P-Wave Arrival

S-Wave Arrival

Surface Wave Arrival

Epicentral Distance

Max Amplitude

Impact Amplitude Map

Epicenter

2 Mw Impact

4 Mw Impact

6 Mw Impact

8 Mw Impact

Earthquake Location and Magnitude Calculation Methods

Locating an Earthquake from Seismograms

Seismologists use the time difference between P-wave and S-wave arrivals to determine the distance to an earthquake epicenter. This method relies on the fact that P-waves travel faster than S-waves through the Earth.

Distance (km) = (Ts - Tp) × (Vp × Vs) / (Vp - Vs)

Where:
Ts = S-wave arrival time
Tp = P-wave arrival time
Vp = P-wave velocity (typically ~6 km/s in the crust)
Vs = S-wave velocity (typically ~3.5 km/s in the crust)

To determine the exact epicenter location, seismologists need data from at least three seismic stations. The process involves:

Calculate the distance from each station to the epicenter using the formula above
Draw a circle around each station with radius equal to the calculated distance
The intersection point of these circles is the earthquake epicenter

Determining Earthquake Magnitude

The magnitude of an earthquake can be calculated from seismogram data using several methods:

Richter Scale (Local Magnitude, ML)

The Richter scale measures the amplitude of the largest seismic wave recorded on a seismogram:

ML = log10(A) - log10(A0)

Where:
A = Maximum wave amplitude measured in micrometers
A0 = Standard reference amplitude

Moment Magnitude Scale (Mw)

The moment magnitude scale is more accurate for larger earthquakes and is based on the seismic moment:

Mw = (2/3) × log10(M0) - 10.7

Where:
M0 = Seismic moment in dyne-centimeters
M0 = μ × A × D
μ = Rigidity of rock
A = Area of fault rupture
D = Average displacement

For each increase of 1 in magnitude, the seismic energy released increases approximately 32 times. This means a magnitude 8 earthquake releases about 32 times more energy than a magnitude 7 earthquake.