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Earthquake Distance Equation:
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The earthquake distance equation estimates the distance to an earthquake's epicenter based on the time difference between the arrival of P-waves and S-waves. This calculation is particularly useful in California where seismic activity is frequent.
The calculator uses the earthquake distance equation:
Where:
Explanation: The equation uses the time difference between seismic wave arrivals multiplied by a constant factor (8 km/s) to estimate distance to the epicenter.
Details: Accurate distance estimation is crucial for earthquake early warning systems, determining the affected area, and coordinating emergency response efforts.
Tips: Enter both P-wave and S-wave arrival times in seconds. The S-wave time must be greater than the P-wave time for accurate calculation.
Q1: Why is the constant factor 8 km/s?
A: This value represents the approximate speed difference between P-waves and S-waves in the Earth's crust, which averages about 8 km/s in California's geological conditions.
Q2: How accurate is this calculation?
A: The calculation provides a good estimate but may vary based on local geology. For precise location determination, data from multiple seismographs is needed.
Q3: What are typical time differences for California earthquakes?
A: Time differences can range from a few seconds for nearby earthquakes to over a minute for distant ones along the San Andreas fault system.
Q4: Can this equation be used worldwide?
A: While the principle applies globally, the constant factor (8) is optimized for California's specific geological conditions and may need adjustment for other regions.
Q5: What's the difference between P-waves and S-waves?
A: P-waves (primary waves) are compression waves that arrive first. S-waves (secondary waves) are shear waves that arrive later and typically cause more damage.