Question

get it? explain how the epicenter of an earthquake can be located using information from three seismic stations.
get it? explain the relationship between the distribution of earthquakes and tectonic plate boundaries.

Explanation:

First Question (Locating Earthquake Epicenter)

1. Each seismic station determines the distance to the epicenter using the time difference between P - waves and S - waves.
2. With this distance, a circle (with the station as the center and distance as radius) is drawn.
3. The intersection of three such circles (from three stations) gives the epicenter.

1. Tectonic plates move, and at their boundaries (convergent, divergent, transform), stress builds up.
2. Convergent: Plates collide (e.g., subduction zones), causing quakes. Divergent: Plates move apart (e.g., mid - ocean ridges), creating quakes. Transform: Plates slide past (e.g., San Andreas Fault), triggering quakes.
3. Most earthquakes occur along these boundaries; some (intra - plate) happen within plates due to old fault reactivation.

Answer:

To locate an earthquake's epicenter with three seismic stations:

1. Distance Calculation: Each station uses the time difference between primary (P - waves) and secondary (S - waves) to find its distance to the epicenter (since P - waves travel faster, the time gap relates to distance).
2. Circle Drawing: For each station, draw a circle with the station as the center and the calculated distance as the radius.
3. Intersection Point: The point where all three circles intersect is the epicenter (two circles intersect at two points; a third circle resolves the ambiguity to one point).

Second Question (Earthquakes and Tectonic Plates)