2026-10-18

Earthquake Magnitude Distribution

Summary: The distribution of earthquake magnitudes is right-skewed and the majority of earthquakes are distributed from 3.875 to 5.125.

Earthquake Depth Distribution

Summary: The majority of the earthquake depths in this distribution are either between 0km to 225km or between 475km and 625 km, showing concentration in the higher and lower ranges.

Magnitude vs Depth

Summary: Earthquake magnitude shows a weak negative relationship with depth.

Linear Regression Model

Predict earthquake magnitude from depth.

\[ \hat{M} = \beta_0 + \beta_1 D \]

Where:

  • \(\hat{M}\) = Predicted Magnitude
  • \(D\) = Earthquake Depth (km)
  • \(\beta_0\) = Intercept
  • \(\beta_1\) = Slope

Model for Magnitude vs. Depth

\[ \hat{M} = 4.755 + (-4.31\times 10^{-4})D \]

Earthquakes Off the Coast of Fiji in 3D

Hypothesis Testing

Investigate whether earthquake magnitude has a statistically significant relationship with depth

Null Hypothesis \[ H_0: \beta_1 = 0 \] A linear relationship between depth and magnitude doesn’t exists.

Alternative Hypothesis

\[ H_1: \beta_1 \neq 0 \] A linear relationship between depth and magnitude exists.

Decision Significance Level: \(\alpha = 0.05\)

P-value: \(1.535 \times 10^{-13} < 0.05\)

Decision: Reject H₀. There is a statistically significant linear relationship.

Statistical Results

Linear Regression Results

  • Slope: ** \(-4.31 \times 10^{-4}\)
  • R^2: 0.0532
  • P-value: \(1.535 \times 10^{-13}\)
  • Sample size: 1000 earthquakes.

Discussion

The slope indicates that earthquake magnitude tends to slightly decrease as depth increases.

\[ R^2 = 0.0532 \] Depth explains around 5.32% of the earthquake magnitude variation.

Conclusion: Although the relationship is statistically significant, depth is not a strong predictor of earthquake magnitude.

Code for the 3D Plot

plot_ly(data = quakes, x = ~long, y = ~lat,
    z = ~depth, color = ~mag, colors = c("#440154",
        "#31688E", "#35B779", "#FDE725"),
    type = "scatter3d", mode = "markers",
    marker = list(size = 3, opacity = 0.5),
    height = 420) %>%
    layout(scene = list(xaxis = list(title = "Longitude"),
        yaxis = list(title = "Latitude"),
        zaxis = list(title = "Depth (km)")),
        margin = list(l = 0, r = 0, b = 0,
            t = 0))

Thank You