Characterizing Stress Orientations in Southern Kansas

Author(s):  
Robert J. Skoumal ◽  
Elizabeth S. Cochran ◽  
Kayla A. Kroll ◽  
Justin L. Rubinstein ◽  
Devin McPhillips

ABSTRACT Induced seismicity predominantly occurs along faults that are optimally oriented to the local principal compressive stress direction, and the characterization of these stress orientations is an important component of understanding seismic hazards. The seismicity rate in southern Kansas rapidly increased in 2013 primarily due to the disposal of large volumes of wastewater into the Arbuckle Group. Previously, local stress orientations in this area were poorly constrained, which limited our understanding of the complex faulting and diverse earthquake mechanisms in this region. We use shear-wave splitting and focal mechanism inversion techniques to create multiple, independent estimates of maximum horizontal stress directions (SHmax) and their spatial variation across the study area. We then create an integrated model of stress orientations for southern Kansas and northern Oklahoma using our local results in conjunction with previous, regional stress orientation estimates. We find that SHmax in both southern Kansas and central Oklahoma exhibits an east-northeast (∼N78° E) orientation, and these regions bound a northeast (∼N59° E) rotation within a ∼20  km area in northern Oklahoma near the Nemaha ridge.

2004 ◽  
Vol 160 (1) ◽  
pp. 332-344 ◽  
Author(s):  
Scott D. Reynolds ◽  
Scott D. Mildren ◽  
Richard R. Hillis ◽  
Jeremy J. Meyer ◽  
Thomas Flottmann

2014 ◽  
Vol 54 (2) ◽  
pp. 1
Author(s):  
Randall Taylor ◽  
Simon Cordery ◽  
Sebastian Nixon ◽  
Karel Driml

This case-study demonstrates seismic processing in the presence of Horizontal Transverse Isotropic (HTI) velocity anisotropy encountered in a low-fold land 3D survey in New Zealand. The HTI velocity anisotropy was unexpected, being suspected only after the initial poor stack response compared to vintage 2D sections in the area, and the sparse 3D design made it difficult to identify. The paper shows how anisotropy was singled out from other possible causes, such as geometry errors. We discuss the key steps of the processing flow incorporated to deal with the HTI anisotropy to attain a high quality final processed volume. In particular we show data examples after the application of azimuthally dependant NMO velocities, along with pre-stack HTI migration. Examples are shown which demonstrate the preservation of the HTI anisotropy before and after 5D trace interpolation. Maps and vertical profiles of 3D attributes are used to demonstrate the magnitude and direction of the HTI velocity field, which varies 5% to 10% between the fast and slow horizontal directions. These observations coincide with the local stress state deduced from borehole break-out studies. We conclude that the fast velocity direction corresponds to the present maximum horizontal stress direction. Finally the paper summarises the implications for processing wide azimuth 3D data in this area and suggests improvements for future 3D survey design. This paper was originally published in the Proceedings of the 23rd International Geophysical Conference and Exhibition, which was held from 11–14 August 2013 in Melbourne, Australia.


Author(s):  
Robert J. Skoumal ◽  
Elizabeth S. Cochran

Abstract Wastewater disposal is primarily responsible for the increased seismicity rate since ∼2013 in southern Kansas. Previous work that used shear-wave splitting (SWS) in southern Kansas interpreted an ∼90° temporal rotation in the fast polarization direction and attributed it to increased pore pressures resulting from fluid injection. However, this interpreted rotation coincided with a change in the stations used to make the SWS measurements. We investigate the temporal variability of fast azimuths in southern Kansas by making SWS measurements on earthquake families with similar source–receiver paths recorded on a stable local seismic network. We select high-quality SWS measurements by investigating the stability of results across 65 different frequency bands between 0.5 and 15 Hz. We find that the fast polarization direction in southern Kansas is relatively constant with an average east-northeast (∼N79°E) orientation between 2014 and 2017. Our fast polarization measurements are primarily a reflection of the maximum principal horizontal stress direction (SHmax). We observe a slight spatial change in SHmax to the northeast (∼N55°E) near the Nemaha ridge in Oklahoma. However, we do not observe any significant temporal rotation of SHmax or variation in delay time (i.e., crack density) in southern Kansas, contrary to the earlier study. The previously interpreted ∼90° rotation may either be a reflection of a very local stress change or a misinterpretation of SWS results potentially due to the use of inconsistent source–receiver paths. Our SWS measurements cover the period of peak wastewater disposal and seismicity rates and suggest an absence of significant temporal rotations in the local anisotropy and stress orientations associated with wastewater disposal.


2021 ◽  
Vol 1 (7) ◽  
pp. 16-24
Author(s):  
Anton E. Antonov ◽  
◽  
Andrei S. Shadrin ◽  
Dmitrii V. Konoshonkin ◽  
Valerii S. Rukavishnikov ◽  
...  

Introduction. The World Stress Map project proves that horizontal stress orientation determination is a global task essential for the majority of geomechanical calculations. However, there is scant data on stress orientations in the territory of Russia at the moment. The task is therefore highly relevant. Research objective is to determine the orientations of maximum and minimum horizontal stresses by separate areas of the Tomsk region and build a map of horizontal stresses. Method of research. The basis for determining the orientations of horizontal stresses is the theory of drilling-induced fracture and borehole breakouts occurrence. The maximum stress orientation coincides with the drilling-induced fracture orientation, whereas the minimum stress orientation coincides with the borehole breakouts orientation or is perpendicular to the maximum stresses. Results. Research results are compiled in a summary table containing mean orientations of horizontal stresses by areas and a map of horizontal stress orientations. Conclusions. A summary map of maximum horizontal stress strike azimuths has been constructed. The stresses are of similar orientation in every well under consideration, except for a well in the North-Shingin area. The average value of maximum horizontal stress orientation has made up 337° northwest and 157° southeast.


Author(s):  
Angie D. Ortega-Romo ◽  
Jacob I. Walter ◽  
Xiaowei Chen ◽  
Brett M. Carpenter

Abstract To better understand relationships among crustal anisotropy, fracture orientations, and the stress field in Oklahoma and southern Kansas, we conduct shear-wave splitting analysis on the last 9 yr of data (2010–2019) of local earthquake observations. Rather than a predominant fast direction (ϕ), we find that most stations have a primary fast direction of polarization (ϕpri) and a secondary fast direction of polarization (ϕsec). At most stations, either the primary fast direction of polarization (ϕpri) or the secondary fast direction of polarization (ϕsec) is consistent with the closest estimated maximum horizontal stress (σHmax) orientation in the vicinity of the observation. The general agreement between fast directions of polarization (ϕ) and the maximum horizontal stress orientations (σHmax) at the regional level implies that the fast polarization directions (ϕ) are extremely sensitive to the regional stress field. However, in some regions, such as the Fairview area in western Oklahoma, we observe discrepancies between fast polarization directions (ϕ) and maximum horizontal stress orientations (σHmax), in which the fast directions are more consistent with local fault structures. Overall, the primary fast direction of polarization (ϕpri) is mostly controlled and influenced by the stress field, and the secondary fast direction of polarization (ϕsec) likely has some geologic structural control because the secondary direction is qualitatively parallel to some mapped north-striking fault zones. No significant changes in fast directions over time were detected with this technique over the 5 yr (2013–2018) of measurements, suggesting that pore pressure may not cause a significant enough or detectable change above the magnitude of the background stress field.


2021 ◽  
Author(s):  
Abu M. Sani ◽  
Hatim S. AlQasim ◽  
Rayan A. Alidi

Abstract This paper presents the use of real-time microseismic (MS) monitoring to understand hydraulic fracturing of a horizontal well drilled in the minimum stress direction within a high-temperature high-pressure (HTHP) tight sandstone formation. The well achieved a reservoir contact of more than 3,500 ft. Careful planning of the monitoring well and treatment well setup enabled capture of high quality MS events resulting in useful information on the regional maximum horizontal stress and offers an understanding of the fracture geometry with respect to clusters and stage spacing in relation to fracture propagation and growth. The maximum horizontal stress based on MS events was found to be different from the expected value with fracture azimuth off by more than 25 degree among the stages. Transverse fracture propagation was observed with overlapping MS events across stages. Upward fracture height growth was dominant in tighter stages. MS fracture length and height in excess of 500 ft and 100 ft, respectively, were created for most of the stages resulting in stimulated volumes that are high. Bigger fracture jobs yielded longer fracture length and were more confined in height growth. MS events fracture lengths and heights were found to be on average 1.36 and 1.30 times, respectively, to those of pressure-match.


2021 ◽  
Vol 9 ◽  
Author(s):  
José Ángel López-Comino ◽  
Simone Cesca ◽  
Peter Niemz ◽  
Torsten Dahm ◽  
Arno Zang

Rupture directivity, implying a predominant earthquake rupture propagation direction, is typically inferred upon the identification of 2D azimuthal patterns of seismic observations for weak to large earthquakes using surface-monitoring networks. However, the recent increase of 3D monitoring networks deployed in the shallow subsurface and underground laboratories toward the monitoring of microseismicity allows to extend the directivity analysis to 3D modeling, beyond the usual range of magnitudes. The high-quality full waveforms recorded for the largest, decimeter-scale acoustic emission (AE) events during a meter-scale hydraulic fracturing experiment in granites at ∼410 m depth allow us to resolve the apparent durations observed at each AE sensor to analyze 3D-directivity effects. Unilateral and (asymmetric) bilateral ruptures are then characterized by the introduction of a parameter κ, representing the angle between the directivity vector and the station vector. While the cloud of AE activity indicates the planes of the hydrofractures, the resolved directivity vectors show off-plane orientations, indicating that rupture planes of microfractures on a scale of centimeters have different geometries. Our results reveal a general alignment of the rupture directivity with the orientation of the minimum horizontal stress, implying that not only the slip direction but also the fracture growth produced by the fluid injections is controlled by the local stress conditions.


2020 ◽  
Author(s):  
Velio Coviello ◽  
Lucia Capra ◽  
Gianluca Norini ◽  
Norma Dávila ◽  
Dolores Ferrés ◽  
...  

Abstract. The M7.1 Puebla-Morelos earthquake that occurred on 19 September 2017, with epicenter located ∼ 70 km SW from Popocatépetl volcano, severely hit central Mexico. Seismic shaking of the volcanic edifice induced by the earthquake triggered hundreds of shallow landslides on the volcanic flanks, remobilizing loose pyroclastic deposits and saturated soils. The largest landslides occurred on the slopes of aligned ENE-WSW-trending ravines on opposite sides of the volcanic cone, roughly parallel to the regional maximum horizontal stress and local volcanotectonic structural features. This configuration may suggest transient reactivation of local faults and extensional fractures as one of the mechanisms that has weakened the volcanic edifice and promoted the largest slope failures. The seismic records from a broadband station located at few kilometers from the main landslides are used to infer the intensity of ground shaking that triggered the slope failures. The material involved in the larger landslides, mainly ash and pumice fall deposits from late Holocene eruptions with a total volume of about 106 cubic meters, transformed into two large debris flows on the western slope of the volcano and one on its eastern side. The debris flows were highly viscous and contained abundant large woods (about 105 cubic meter). Their peculiar rheology is reconstructed by field evidences and analyzing the grain size distribution of samples from both landslide scars and deposits. This is the first time that such flows were observed at this volcano. Our work provides new insights to constrain a multi-hazard risk assessment for Popocatépetl and other continental active volcanoes.


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