The Era of "Techno-tonics"

I decided it was essential to affix some theoretical proof of cases where human activity has been accountable for causing geological hazards. To begin with, there are copious examples of how the construction of sizeable dams can be linked to seismic activity in recent years. For instance, the Great Quake of Sichuan in 2008 was responsible for the deaths of 80,000 people. However, many pass the blame onto the recently built Zipingpu dam, situated barely 5 kilometers from the epicenter. Dr V. P. Jauhari’s coins Reservoir-Induced Seismicity (RIS) as being “… related to the extra water pressure created in the micro-cracks and fissures in the ground under and near a reservoir. When the pressure of the water in the rocks increases, it acts to lubricate faults which are already under tectonic strain, but are prevented from slipping by the friction of the rock surfaces.”

In spite of inexorable research, scientists are yet to negotiate a homogenous explanation for RIS that would help model diverse geological regions or predict where the phenomenon could manifest. However the following characteristics; found in the ‘International Rivers’ Factsheet; have been accepted:

• The most important factor controlling RIS is the depth of water in the reservoir. 
• Volume of water is also a critical variable that can instigate earthquakes.
• Additional factors include local geology and historic seismic stress patterns in the region.
• The construction of reservoirs can shift increased earthquake risk to areas with previously low frequency seismic activity.
• RIS cases show that the area within 10-15 kilometres of impounded reservoirs suffers an increased rate of activity.
• RIS can be rapid - noticed following the initial filling stages of the reservoir.
• Conversely the effect can be delayed until later in the life of the reservoir.
• Some minor cases have struck during the filling process. 

It is important to note that reservoirs themselves are unable to produce adequate seismic energy to induce an earthquake. Despite many case studies – Koyna, India (1967) and Xinfengjiang Dam, China (1962) – exhibiting evidence of a strong cause-effect relationship, this rarely occurs where the earth’s crust is not already at breaking point. Essentially, the reservoir can stir up an earthquake event, which would otherwise have bided its time for hundreds or thousands of years (Gupta, 2002). Unsurprisingly, the engineering community have been disinclined to accept the danger of RIS. Groups such as the International Commission on Large Dams have stubbornly insisted that RIS should only be regarded for reservoirs deeper than 100 meters.

Worryingly, many dams currently under construction or planning are to be located in the world’s most seismically active regions, an example being the Himalayas. This is why evidence suggests that the advancement in technology on a global scale could severely alter tectonic activity, potentially introducing an era of "techno-tonics". Major dam-building schemes are lined up for other seismic hotspots including Iran, Turkey, Patagonia, Mexico and Central America (see map below). In response to the Sichuan Quake, geological experts in southwest China have successfully appealed for the right to suspend approval of large dams in geologically unstable areas until the risk of RIS has been addressed (Kerr & Stone, 2009).