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The uncertainty of science: Geologists have assembled a database of more than 700 earthquakes they think might have been caused by human activity.
The Human-Induced Earthquake Database, or HiQuake, contains 728 examples of earthquakes (or sequences of earthquakes) that may have been set off by humans over the past 149 years. Most of them were small, between magnitudes 3 and 4. But the list also includes several large, destructive earthquakes, such as the magnitude-7.8 quake in Nepal in April 2015, which one paper linked to groundwater pumping.
Miles Wilson, a hydrogeologist at Durham University, UK, and his colleagues describe the database in a paper set to be published on October 4 in Seismological Research Letters2. The scientists say that HiQuake is the biggest, most up-to-date public listing of human-caused quakes ever made. By bringing the data together in this way, they hope to highlight how diverse induced quakes can be — and help society to understand and manage the future risk.
Many of these quakes were likely caused by human activity. Many however might not have been. The jury is still out, as the article reluctantly admits near the end.
All possible instances of induced quakes were included “without regard to plausibility”, writes the team, because of the difficulty involved in deciding what constitutes absolute proof that an earthquake was caused by human activity. But that could mislead people about the real hazard from induced quakes, says Raphaël Grandin, a geophysicist at the Institute of Earth Physics in Paris. “When you put a dot in the database, and a scientific reference behind it, then you may lead the non-expert to think that the earthquake was caused by humans,” he says. Such a listing might hide scientific uncertainty, as with the Chinese quake: despite the paper linking it to reservoir filling, many seismologists do not believe it was triggered by human activity.
In other words, they included every quake that had the slightest suggestion it was connected to human activity, without noting the uncertainties. This makes this database to me somewhat suspect. Rather than identify the known reliable links between human activity and quakes in order to learn what causes them, this database seems more designed as a political propaganda tool aimed at limiting future human activity. It certainly doesn’t clarify our knowledge on this subject, but instead muddies the water significantly.