What are foreshocks?

Foreshocks are defined as minor tremors that occur before a larger seismic event or major earthquake. These smaller earthquakes can happen minutes, days, or even weeks prior to the main shock and are often difficult to distinguish from regular earthquake activity. While they may not always precede a larger quake, when they do, they can provide essential clues for seismologists to understand the dynamics of the area and potentially improve earthquake prediction efforts.

The other options describe different seismic phenomena. Minor earthquakes following a major one are termed aftershocks, whereas earthquakes that occur during volcanic eruptions are related to volcanic activity and not considered foreshocks. Earthquakes caused by landslides typically arise from the sudden movement of rock and earth material, which is a different mechanism altogether and does not qualify as a foreshock in the context of tectonic activity. Understanding foreshocks helps scientists monitor seismic patterns and can contribute to developing early warning systems.