Aftershock seismicity propagated to the southwest and revealed previously unknown fault segments. Here, Ellsworth explains what failed in Pohang and how their analysis could help lower risks for not only the next generation of geothermal plants, but also fracking projects that rely on similar technology.
The 2017 Pohang earthquake, measuring magnitude 5.4 on the moment magnitude scale, struck Heunghae, Pohang, North Gyeongsang Province, South Korea on November 15 2017. Aftershocks from the 2017 Pohang Earthquake reveal a complex fault geometry. Seismicity propagated to the southwest and revealed unknown fault segments. The hypocentral distribution of the earthquake sequence reveals the reactivation of a complex subsurface fault system that was previously unmapped. 2017 Pohang earthquake The 2017 Pohang earthquake, measuring magnitude 5.4 on the moment magnitude scale, struck Heunghae, Pohang, North Gyeongsang Province, South Korea on November 15 2017. “There is no doubt,” said Stanford geophysicist William Ellsworth. Latest Stanford Health Alerts on COVID-19, Conventional geothermal resources have been generating commercial power for decades in places where heat and water from burble up through naturally permeable rock. The carbon intensity of the U.S. power sector reached a new low in 2019, more than a third below its 2005 level, according to a new analysis from Carnegie-Mellon University. And the earthquakes kept getting bigger as time went by. In March 2019, a government-commissioned research team in South Korea concluded after a year-long study that the 5.4-magnitude earthquake that rattled the city of Pohang in November 2017 … Professor Adam Brandt provide NGI's recent Natural Gas Brief, Prof. Inês M.L. This was a particularly dangerous place. Research now shows that development of a geothermal energy project shoulders the blame.
By some estimates, it could amount to as much as 10 percent of current U.S. electric capacity. The Pohang area in southeastern Korea was shocked by a Mw 5.4 earthquake in 15 November 2017. It is also difficult to assess the effect of EGS activity on seismicity. “We have understood for half a century that this process of pumping up the Earth with high pressure can cause earthquakes,” said Ellsworth, who co-directs the Stanford Center for Induced and Triggered Seismicity and is a professor in the School of Earth, Energy & Environmental Sciences (Stanford Earth). Many geothermal, oil and gas projects have also been guided by a hypothesis that as long as you don’t put more than a certain volume of fluid into a well, you won’t get earthquakes beyond a certain size. ELLSWORTH: Natural geothermal systems are an important source of clean energy. On a November afternoon in 2017, a magnitude 5.5 earthquake shook Pohang, South Korea, injuring dozens and forcing more than 1,700 of the city’s residents into emergency housing. (or is it just me...), Smithsonian Privacy There may be some truth to that in some places, but the experience in Pohang tells us it’s not the whole story.
But they are rare and pretty much tapped out. Sometimes these tiny fractures make tiny little earthquakes. Copyright © 2020 Elsevier B.V. or its licensors or contributors. School of Earth, Energy & Environmental Sciences, Shared Analytical Facilities and Research Resources, Stanford Center for Induced and Triggered Seismicity, Postdoctoral Research Fellow Evan Sherwin and Assoc. Once the ruptures initiated, their destined magnitudes are mostly confined by the potency of the fault. But the risk is very much higher in the city. Think of it this way: An earthquake as large as Pohang poses the same hazard whether it strikes in a densely populated city or an uninhabited desert. They pump water into the well at high pressure, forcing open existing fractures or creating new ones. As soon as the Pohang earthquake occurred, there has been a considerable controversy over the potential for a causal connection between the destructive earthquake … It was the second largest earthquake and the most damaging earthquake during the instrumental seismic observation period in Korea.
Hazard is a potential source of harm or danger. If we can assign a probability to earthquakes of different magnitudes, then civil authorities can decide whether or not they want to accept the risk and under what terms. On November 15, 2017, at 2.29 p.m., a 5.4 magnitude earthquake struck Pohang City in South Korea. If we can figure out how to safely develop power plants based on enhanced geothermal systems technology, it’s going to have huge benefits for all of us. As soon as the Pohang earthquake occurred, there has been a considerable controversy over the potential for a causal connection between the destructive earthquake and industrial activities to develop enhanced geothermal system (EGS) due to their proximity (only a few hundred meters). Maybe you would decide that this is not such a good idea at all. This pattern suggests that the stress in the mainshock area was almost completely released during the mainshock and early aftershock phase, and that the recurrence of moderate to large earthquakes in the hypocentral area is unlikely compared with the marginal areas. ScienceDirect ® is a registered trademark of Elsevier B.V. ScienceDirect ® is a registered trademark of Elsevier B.V. © 2019 Elsevier B.V. All rights reserved.