CANARY ISLANDS - Canary Islands hit by 'seismic swarm' as Tenerife records 11 earthquakes in one morning. Shallow tremors can indicate magma movement or changes in geothermal systems, sometimes serving as early warnings of eruptions. In the past 24 hours six tremors with a magnitude of up to 2.4 were also reported in Santa Cruz. All of the tremors occurred at shallow depths, between zero and 13 kilometres below the surface. A shallow earthquake occurring at these depths is significant because it happens close to the Earth’s surface, where seismic waves have little distance to travel before reaching the ground. This means the energy does not dissipate much, so even moderate quakes can cause strong shaking and damage to buildings and infrastructure. Such shallow events are usually linked to tectonic activity along faults in the Earth’s crust, where pressures accumulate and are abruptly released.