The role that humans play in climate change took a stunning turn with a study published in Nature Geoscience. Using satellite imagery and computer models, researchers investigated the geologic events surrounding the May 11, 2011 earthquake in Lorca, Italy.
Two characteristics stood out: the magnitude of the event and its depth. The earthquake registered 5.1 magnitude and occurred at a relatively shallow depth of less than four km. The latter caused the massive damage it caused.
Evidence of a Human-Related Cause
The researchers found that satellite imagery revealed subtle changes in elevation in the area where the earthquake occurred. They also discovered significant changes in the water table over the last 50 years that may offer an explanation.
Records indicate that the water table dropped 250 meters during this time period. This change created a vacuum underground. It also removed weight on the underlying rock that caused it to pop up and buckle.
The situation in Italy is not unique. Other areas around the world, including California’s San Joaquin Valley, present a similar threat. The other risk factor lies with climate change.
While this study did not link the event to climate change, it is a logical association. Scientists have warned of an increased risk of drought as a result of climate change. California has already experienced the consequences of pressure on water demand with drawdowns in hydropower.
Humans and Groundwater
The study shows that humans can affect their environment in other ways that climate change can exacerbate. Unchecked demands on groundwater can lead to similar events in other areas.
Across the planet, groundwater resources provide between 25 and 40 percent of the world’s drinking water. Geology and demand can lead to losses that cannot be replenished quickly enough to prevent this type of seismic activity. Drought can increase its likelihood.
Earthquakes occur for a number of reasons that have nothing to do with human activity. This study shows that some cases, humans can play a role. Recognizing this potential is essential, especially in areas where groundwater depletion is an issue. The earthquake in Lorca reveals another of the many complexities of climate change.