Ellsworth earthquakes in unusual locations have become an important topic of discussion in both north america and europe, owing to the concern that industrial activity could cause damaging earthquakes. An earthquake is what happens when two blocks of the earth suddenly slip past one another. Currently used models relating the maximum magnitude of injectioninduced earthquakes to injection parameters do not incorporate rupture physics. Probabilistic assessment of potential fault slip related to. Injectioninduced seismicity and faultslip potential in. In that study, it was concluded that data collected from 18 different case studies of injection induced seismicity supported the proposed relationship between maximum magnitude and injection volume. Usgs and its university partners have also deployed seismometers at sites of known or possible injectioninduced earthquakes in arkansas, southern colorado, oklahoma and ohio. The surface where they slip is called the fault or fault plane. Hydraulic fracturing a gas and petroleum recovery process that uses fluid injection to open fissures in rock to allow trapped gas or crude oil to flow through a pipe to a wellhead at the surfacewas also shown to cause earthquakes and was found to be the primary cause of induced earthquakes in british columbia and western alberta as well. We utilize quantitative risk assessment qra to calculate the conditional probability of slip on mapped faults in response to injection related increases in pore pressure in northcentral oklahoma usa where widespread injection of produced saltwater has triggered thousands of small to mediumsized earthquakes in the past 7 yr. Induced earthquakes were simulated with a coupled fluid flow and quasidynamic earthquake rupture model. Ogs fluid injection induced seismicity workshop, july 16, 20 summary. Hough, shaking from injection induced earthquakes in the central and eastern united states, bulletin of the seismological society of am. Shapiro therefore concluded that a large portion of a preexisting fault surface must be stimulated by injection in order to induce an.
We develop theoretical estimates, validated by simulations, of the size of ruptures induced by localized pore. Induced earthquakes, reservoir induced or otherwise, appear to be triggered by very small stress changes, sometimes only a small fraction of one bar. Plain language summary studies of the triggering mechanisms of injection. It has long been understood that earthquakes can be induced by impoundment of reservoirs, surface and underground mining, withdrawal of fluids and gas from the subsurface, and injection of fluids into. Shaking from injectioninduced earthquakes in the central and. This energetic sequence has produced five earthquakes with m w 4. Globally, the koyna dam creating shivajisagar lake in maharashtra, india, continues to be the most significant site of reservoir induced earthquakes. Potential injectioninduced seismicity associated with oil. It has long been known that impoundment of reservoirs, surface and. Although the immediate cause of injectioninduced earth quakes is the increase of fluid pressure that brings a fault to a critical stress state, models of the spatial.
Induced seismic risk varies tremendously by region, and that has implications for managing waste disposal operations. Once an exploration well has been drilled, it is possible to perform trial injections and analyse, perhaps in realtime, the attributes of the microseismicity that is produced, such as momentfrequency relations. Results of ongoing multiyear research on induced earthquakes by the united states geological survey usgs published in 2015 suggested that most of the significant earthquakes in oklahoma, such as the 1952 magnitude 5. Usgs and its university partners have also deployed seismometers at sites of known or possible injection induced earthquakes in arkansas, southern colorado, oklahoma and ohio. Injectioninduced earthquakes have, in particular, become a focus of discussion as the application of hydraulic fracturing to tight shale formations is enabling the.
Scott phillips, earthquakes induced by hydraulic injections at yosemite national park, abstract eos trans. A few sites regularly have larger quakes, such as the geysers geothermal plant in california which averaged two m4 events and 15 m3 events every year from 2004 to 2009. Figure 3 shows locations of earthquakes with magnitudes equal to or greater than 3. It has long been understood that earthquakes can be induced by impoundment of. Pdf managing injectioninduced seismic risks researchgate. The location below the earths surface where the earthquake starts is called the hypocenter, and the. Hough, shaking from injectioninduced earthquakes in the central and eastern united states, bulletin of the seismological society of am. Nonstructural damage reported in earthquakes as small as m 3 in rare cases injection induced earthquakes are typically smaller than m 5 currently, there is no generalized u. Keranen and others, march 20 science, american assoc. Shaking from injectioninduced earthquakes in the central and eastern united states. Saltwater injection, induced earthquakes and pressure increase in oklahoma and kansas. Myths and facts on wastewater injection, hydraulic.
Sep 23, 2016 shaking from injection induced earthquakes in the central and eastern united states. There are now over 70 known cases of reservoirinduced earthquakes. The fourth paper deals with water injection induced seismic activity, while the remaining 12 papers treat several aspects of water reservoir induced earthquakes. Because this field had an extensive history of induced earth.
For context, we make comparisons with planned ccs projects in the uk. Injection induced earthquakes have, in particular, become a focus of discussion as the application of hydraulic fracturing to tight shale formations is enabling the production of oil and gas from previously unproductive formations. This greatly enriches the information that is available for seismic hazard assessment and may. In that study, it was concluded that data collected from 18 different case studies of injectioninduced seismicity supported the proposed relationship between maximum magnitude and injection volume. Injectioninduced earthquakes have, in particular, become a focus of discussion as the application of hydraulic fracturing to tight shale formations is enabling the production of oil and gas from. In the context of injectioninduced seismicity, the processes that. Modeling injectioninduced seismicity with the physicsbased. Healy, et al, geophysical and geological investigations relating to earthquakes in the denver area, colorado, u. Earthquakes in unusual locations have become an important topic of discussion in both north america and europe, owing to the concern that industrial activity could cause damaging earthquakes.
Bulletin of the seismological society of america, v. We develop theoretical estimates, validated by simulations, of the size of ruptures induced by localized porepressure. Injectioninduced earthquakes pose a serious seismic hazard but also offer an opportunity to gain insight into earthquake physics. The injection depth above the crystalline basement was the most important parameter when considering. Shaking from injection induced earthquakes in the central and eastern united states. A brief overview congressional research service summary the development of unconventional oil and natural gas resources using horizontal drilling and highvolume hydraulic fracturing has created new demand for wastewater disposal wells that inject waste fluids into deep geologic strata. Geological survey open file report 960011 reservoirinduced seismicity the potential for reservoirinduced seismicity, which is the triggering of earthquakes by the physical processes that accompany the impoundment of large reservoirs, was recognized during the seismic hazard studies for the original auburn dam. How large are the earthquakes induced by fluid injection. May 09, 2018 an implicit assumption was made that earthquakes must be confined to regions that experience pressure change. It has long been known that impoundmen t of reservoirs. We argue that, yes, small earthquakes do matter, and their interaction may be an important triggering mechanism to consider.
Several recent studies have presented evidence that significant induced earthquakes occurred in a number of oilproducing regions during the early and midtwentieth century related to either production or wastewater injection. Humaninduced earthquak es have become an importan t topic of political and scien. Quantifying their contribution presents difficult challenges that will require new research into the physics of induced earthquakes and the potential for inducing largemagnitude events. Injection induced earthquakes, such as those that struck in 2011, clearly contribute to the seismic hazard. A brief overview congressional research service summary the development of unconventional oil and natural gas resources using horizontal drilling and hydraulic fracturing fracking has created new demand for wastewater disposal wells that inject waste fluids into deep geologic strata. Injectioninduced earthquakes have, in particular, become a focus of discussion as the application of hydraulic fracturing to tight shale formations is enabling the production of oil and gas from previously unproductive formations. Humaninduced earthquakes have become an important topic of political and scien. The primary cause of these earthquakes, which can reach magnitude 3. Induced seismicity provides insight into why earthquake.
The largest of these induced events was a magnitude 5. Other information on triggered or induced seismicity. Injection induced earthquakes have, in particular, become a focus of discussion as the application of hydraulic fracturing to tight shale formations is enabling the production of oil and gas from. Induced seismicity refers to typically minor earthquakes and tremors that are caused by human activity that alters the stresses and strains on the earths crust.
Ellsworth, william 20 injectioninduced earthquakes, science 341, 1225942, doi. Earthquakes occur frequently in and around kentucky, but most of them are too small to be felt. Since the publication of the first dams and earthquakes in 1976, the phenomenon of reservoir induced seismicity ris is more widely understood. In response to the marked number of injectioninduced earthquakes in northcentral oklahoma, regulators recently called for a 40% reduction in the volume of saltwater being injected in the seismically active areas. Significance for secure co2 storage of earthquakes induced. An implicit assumption was made that earthquakes must be confined to regions that experience pressure change. Humaninduced earthquakes have become an important topic of political and scienti. Currently used models relating the maximum magnitude of injection induced earthquakes to injection parameters do not incorporate rupture physics. For example, earthquakes felt in some oil and gas producing regionssuch as the eagle ford in south texasare associated with fluid extraction, while. Are earthquakes induced by fluidinjection activities always. Most of this seismicity occurred away from regionally mapped faults, challenging efforts to constrain the continuing hazards of injectioninduced seismicity in the basin. International analysis shaking from injectioninduced. We present a calibrated statistical model that predicts that widely felt m.
Shaking from injectioninduced earthquakes in the central. Although these earthquakes were by no means devastating, they did occasion extensive attention and concern in the denver area. In this study i consider the ground motions generated by 11 moderate mw4. Injection induced earthquakes pose a serious seismic hazard but also offer an opportunity to gain insight into earthquake physics. Pdfs were downloaded, digitally filed, and entered into endnote. Key concepts of earthquake science, such as magnitude, surface effects, and ground motion the magnitude and depth of induced seismic events relative to natural. Maximum magnitude estimations of induced earthquakes at. Ogs statement about the cause of 2011 prague earthquake sequence. Are earthquakes induced by fluidinjection activities. How will induced seismicity in oklahoma respond to.
Human activity can induced earthquakes in two ways w. In recent years a consensus in the scientific community has emerged that, while hydraulic fracturing fracking rarely causes earthquakes large enough to be felt, the disposal of waste fluids produced in fracking operations in deep injection wells can, in some cases, induce earthquakes on nearby faults. Geology, geological society of america potentially induced earthquakes in oklahoma, by katie m. The mechanism of induced seismicity download ebook pdf. We utilize quantitative risk assessment qra to calculate the conditional probability of slip on mapped faults in response to injectionrelated increases in pore pressure in northcentral oklahoma usa where widespread injection of produced saltwater has triggered thousands of small to mediumsized earthquakes in the past 7 yr. The largest earthquake reported to date to be induced by fluid injection is m 5. Recent earthquakes in oklahoma and the midcontinent. Hydromechanical and frictional faulting behavior of fluidinjection. The science behind earthquakes what is an earthquake. Injectioninduced earthquakes, such as those that struck in 2011, clearly contribute to the seismic hazard. United states are caused by the deep injection of briny wastewater from oil and gas production into underground formations for disposal. Understanding induced seismicity chapter highlights this chapter discusses the following. Scott phillips, earthquakes induced by hydraulic injections at yosemite.
Ogs statement on usgs maps of potential groundshaking hazards 2017 pdf april 21, 2015 ogs statement on oklahoma earthquakes. Wastewater injection has induced earthquakes in oklahoma, but the relative importance of operational and geologic parameters in triggering such earthquakes is unclear. Injectioninduced earthquakes are thought to be caused by pressure changes due to excess fluid injected deep below the surface and are being dubbed manmade earthquakes. Ellsworth, 20, injectioninduced earthquakes, science 341, 1225942 20. Ellsworth, william 20 injectioninduced earthquakes. Induced seismicity impacts of unconventional oil and gas. Current understanding of induced seismicity in the united states. For examples of induced earthquakes listed in table 1, the calculated stress changes in the seismogenic zone are remarkably small, typically a few percent of the stress drop of the induced earthquake. Probabilistic assessment of potential fault slip related. Ellsworth, william 20 injection induced earthquakes, science 341, 1225942, doi.