Exposing the Hidden Dangers of Dam-Induced Earthquakes
Earthquakes can be induced by dams. Globally, there are over 100 identified cases of earthquakes that scientists believe were triggered by reservoirs (see Gupta 2002). The most serious case may be the 7.9-magnitude Sichuan earthquake in May 2008, which killed an estimated 80,000 people and has been linked to the construction of the Zipingpu Dam.
How Do Dams Trigger Earthquakes?
In a paper prepared for the World Commission on Dams, Dr. V. P Jauhari wrote the following about this phenomenon, known as Reservoir-Induced Seismicity (RIS): “The most widely accepted explanation of how dams cause earthquakes is 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.”
Given that every dam site has unique geological characteristics, it is not possible to accurately predict when and where earthquakes will occur. However, the International Commission on Large Dams recommends that RIS should be considered for reservoirs deeper than 100 meters.
What Are Some Characteristics of RIS?
A leading scholar on this topic, Harsh K. Gupta, summarized his findings on RIS worldwide in 2002:
- Depth of the reservoir is the most important factor, but the volume of water also plays a significant role in triggering earthquakes.
- RIS can be immediately noticed during filling periods of reservoirs.
- RIS can happen immediately after the filling of a reservoir or after a certain time lag.
Many dams are being built in seismically active regions, including the Himalayas, Southwest China, Iran, Turkey, and Chile (see map). International Rivers calls for a moratorium on the construction of high dams in earthquake-prone areas.
Click here for the factsheet on RIS worldwide.
Problems With Big Dams
By 2015, the dam industry had choked more than half of the Earth’s major rivers with some 57,000 large dams. The consequences of this massive engineering program have been devastating. The world’s large dams have wiped out species; flooded huge areas of wetlands, forests and farmlands; and displaced tens of millions of people.
Courtesy of James Syvitski at Colorado University, who produced the video with Bob Stallard of the USGS and Albert Kettner at CSDMS. Data from Alex de Sherbinin (CIESIN, University of Colorado), and Bernhard Lehner (Department of Geography, McGill University).
The “one-size-fits-all” approach to meeting the world’s water and energy needs is also outdated: better solutions exist. While not every dam causes huge problems, cumulatively the world’s large dams have replumbed rivers in a massive experiment that has left the planet’s freshwaters in far worse shape than any other major ecosystem type, including tropical rainforests. In response, dam-affected communities in many parts of the world are working to resolve the legacies of poorly planned dams. Elsewhere (and especially in North America), communities are starting to take down dams that have outlived their usefulness, as part of a broader river restoration movement.
- Frequently Asked Questions
- Watch We All Live Downstream for a visual introduction to dams, rivers and people.
- Read 10 Things You Should Know About Dams
- Read “Greenwashing Hydropower“: The Problems with Big Dams.
- Watch Hydropower: Not As Clean As You Think for an introduction to why big dams are not the answer to our changing climate.
- Damned Rivers, Damned Lives: The case against large dams
- A Crisis of Mismanagement: Real solutions to the world’s water problems
- Beyond Hydropower: Energy options for the 21st century
- Warming the Earth: Hydropower threatens efforts to curb climate change
- The Coming Storm: Preparing for a warming water world