scholarly journals The Oklahoma Geological Survey Statewide Seismic Network

2019 ◽  
Vol 91 (2A) ◽  
pp. 611-621 ◽  
Author(s):  
Jacob I. Walter ◽  
Paul Ogwari ◽  
Andrew Thiel ◽  
Fernando Ferrer ◽  
Isaac Woelfel ◽  
...  

Abstract The Oklahoma Geological Survey (OGS) monitors seismicity throughout the state of Oklahoma utilizing permanent and temporary seismometers installed by OGS and other agencies, while producing a real-time earthquake catalog. The OGS seismic network was recently added to the Advanced National Seismic System (ANSS) as a self-supporting regional seismic network, and earthquake locations and magnitudes are automatically reported through U.S. Geological Survey and are part of the ANSS Comprehensive Earthquake Catalog. In Oklahoma, before 2009, background seismicity rates were about 2 M 3.0+ earthquakes per year, which increased to 579 and 903 M 3.0+ earthquakes in 2014 and 2015, respectively. After seismicity peaked, the rate fell to 624, 304, and 194 M 3.0+ earthquakes in 2016, 2017, and 2018, respectively. The catalog is complete down to M 2.2 from mid-2014 to present, despite the significant workload for a primarily state-funded regional network. That astonishing uptick in seismicity has been largely attributed to wastewater injection practices. The OGS provides the Oklahoma Corporation Commission, the agency responsible for regulating oil and gas activities within the state, with technical guidance and earthquake products that inform their “traffic-light” mitigation protocol and other mitigating actions. We have initiated a citizen-scientist-driven, educational seismometer program by installing Raspberry Shake geophones throughout the state at local schools, museums, libraries, and state parks. The seismic hazard of the state portends a continued need for expansion and densification of seismic monitoring throughout Oklahoma.

Author(s):  
Joan Gomberg ◽  
Paul Bodin

ABSTRACT This study addresses questions about the productivity of Cascadia mainshock–aftershock sequences using earthquake catalogs produced by the Geological Survey of Canada and the Pacific Northwest Seismic Network. Questions concern the likelihood that future moderate to large intermediate depth intraslab earthquakes in Cascadia would have as few detectable aftershocks as those documented since 1949. More broadly, for Cascadia, we consider if aftershock productivities vary spatially, if they are outliers among global subduction zones, and if they are consistent with a physical model in which aftershocks are clock-advanced versions of tectonically driven background seismicity. A practical motivation for this study is to assess the likely accuracy of aftershock forecasts based on productivities derived from global data that are now being issued routinely by the U.S. Geological Survey. For this reason, we estimated productivity following the identical procedures used in those forecasts and described in Page et al. (2016). Results indicate that in Cascadia we can say that the next intermediate depth intraslab earthquake will likely have just a few detectable aftershocks and that aftershock productivity appears to be an outlier among global subduction zones, with rates that on average are lower by more than half, except for mainshocks in the upper plate. Our results are consistent with a clock-advance model; productivities may be related to the proximity of mainshocks to a population of seismogenic fault patches and correlate with background seismicity rates. The latter and a clear correlation between productivities with mainshock depth indicate that both factors may have predictive value for aftershock forecasting.


Author(s):  
Joan Gomberg ◽  
Paul Bodin

ABSTRACT This study addresses questions about the productivity of Cascadia mainshock–aftershock sequences using earthquake catalogs produced by the Geological Survey of Canada and the Pacific Northwest Seismic Network. Questions concern the likelihood that future moderate to large intermediate depth intraslab earthquakes in Cascadia would have as few detectable aftershocks as those documented since 1949. More broadly, for Cascadia, we consider if aftershock productivities vary spatially, if they are outliers among global subduction zones, and if they are consistent with a physical model in which aftershocks are clock-advanced versions of tectonically driven background seismicity. A practical motivation for this study is to assess the likely accuracy of aftershock forecasts based on productivities derived from global data that are now being issued routinely by the U.S. Geological Survey. For this reason, we estimated productivity following the identical procedures used in those forecasts and described in Page et al. (2016). Results indicate that in Cascadia we can say that the next intermediate depth intraslab earthquake will likely have just a few detectable aftershocks and that aftershock productivity appears to be an outlier among global subduction zones, with rates that on average are lower by more than half, except for mainshocks in the upper plate. Our results are consistent with a clock-advance model; productivities may be related to the proximity of mainshocks to a population of seismogenic fault patches and correlate with background seismicity rates. The latter and a clear correlation between productivities with mainshock depth indicate that both factors may have predictive value for aftershock forecasting.


2019 ◽  
Vol 3 (1) ◽  
pp. 1-8
Author(s):  
Sarmistha R. Majumdar

Fracking has helped to usher in an era of energy abundance in the United States. This advanced drilling procedure has helped the nation to attain the status of the largest producer of crude oil and natural gas in the world, but some of its negative externalities, such as human-induced seismicity, can no longer be ignored. The occurrence of earthquakes in communities located at proximity to disposal wells with no prior history of seismicity has shocked residents and have caused damages to properties. It has evoked individuals’ resentment against the practice of injection of fracking’s wastewater under pressure into underground disposal wells. Though the oil and gas companies have denied the existence of a link between such a practice and earthquakes and the local and state governments have delayed their responses to the unforeseen seismic events, the issue has gained in prominence among researchers, affected community residents, and the media. This case study has offered a glimpse into the varied responses of stakeholders to human-induced seismicity in a small city in the state of Texas. It is evident from this case study that although individuals’ complaints and protests from a small community may not be successful in bringing about statewide changes in regulatory policies on disposal of fracking’s wastewater, they can add to the public pressure on the state government to do something to address the problem in a state that supports fracking.


2020 ◽  
Vol 23 (11) ◽  
pp. 1291-1312
Author(s):  
N.V. Zyleva

Subject. This article discusses the practice of ensuring the economic security of oil and gas companies operating under the terms of production sharing agreements, where minerals are the object of security. Objectives. The article aims to justify the need to apply professional judgment in the organization of reliable accounting of minerals, explored and extracted under the terms of the production sharing agreement implementation, to avoid various risks to the entity's economic security. Methods. For the study, I used the methods of deduction and modeling. Results. The article presents proposals to arrange accounting of intangible exploration assets (geological information on mineral reserves) and finished products (the part of the extracted minerals owned by the investor and the part owned by the State). Conclusions. As strategic minerals, oil and gas are the targets of various economic risks. Professionals familiar with the specifics of accounting operations in the implementation of the production sharing agreement should be prepared to prevent these risks. The results obtained can be used to design accounting policies and develop local regulations on the tasks and functions of the economic security service of the organization implementing the production sharing agreement.


2021 ◽  
Vol 3 (11) ◽  
pp. 6-12
Author(s):  
Lyudmila V. Goloshchapova ◽  
◽  
Elena V. Maltseva ◽  

The study is devoted to the analysis of the balance sheet profit of the leading companies in the oil and gas industry. The types of profits were considered, as well as the dynamics of the changes in indicators affecting their formation were analyzed. In addition, the article considers the composition and struc-ture of the balance sheet profit, factors affecting its size. Based on the financial statements of the companies, an idea of the state of profit in the companies «Rosneft», «Lukoil», «Gazprom» and «Tatneft» has been com-piled. The paper analyzes quantitative statistical indicators that reflect the results achieved from 2016–2020.


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