Which activity can cause an earthquakes pattern anomaly?

• A. Erosion by rivers.
• B. Underground mining or oil extraction.
• C. Global warming.
• D. Volcanic eruption.

Answer: (B)

Pattern anomalies in earthquakes often arise when rocks are disturbed by human activities that change underground stress and fluid pressures. Underground mining or oil extraction does this directly: removing rock mass and moving fluids around alters the pressure on faults, creates new fractures, and can trigger clusters of small earthquakes or even larger events near the activity. This produces a seismic pattern that doesn't fit purely natural tectonic sequences. In contrast, erosion by rivers mainly reshapes the surface and doesn’t significantly change deep stresses; global warming is a climate process with no direct short-term seismic trigger; volcanic eruptions can cause earthquakes, but those are tied to magma movement and localized to volcanic regions. So, the activity most likely to cause an earthquakes pattern anomaly is underground mining or oil extraction.