Madrid – When on 11 May the earth shook near the Spanish Lorca, nine people were killed. For an earthquake of intensity of 5.1, the effects were unusually large, many buildings in the city were heavily damaged. This is according to an international research team to the fact that the tremors had occurred in an unusually shallow depth of just three kilometers. Normally this would earthquake strength before in much greater depths. The researchers led by Pablo González of the University of Western Ontario in Canada report in the journal "Nature Geoscience" that human activities were probably responsible for the quake. According to her, the water table has dropped by the city in southeastern Spain by continuously pumping the water since 1960 to at least 250 meters. The research team compared satellite images of the area before and after the quake and ground faults examined in the ground. They found that the quake occurred in just three kilometers down to a pre-existing seismic fault line. Near this fault line was pumped from a groundwater layer on a large scale water. This cracks appeared in the Earth's crust, which led to new tensions on the fault line itself, which in the quake set off a lot easier then. The researchers stress that the declining groundwater level has not only triggered the quake. But: "Our results show that human activities could have an impact on how and when earthquakes occur," says the study. "It does not take much to trigger an earthquake," the seismologist Jean-Philippe Avouac writes in an accompanying article in "Nature Geoscience." "Heavy rains may already be sufficient. "There are cases of tremor were recorded, which were caused by human activities such as oil drilling or the creation of reservoirs. "We know how to start earthquakes. But we are far from being able to keep them under control. " Here you can continue reading