A tectonic boundary for the southern Colorado plateau

Brumbaugh, D. S.

doi:10.1016/0040-1951(87)90335-0

Cited by 18 publications

(22 citation statements)

References 9 publications

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“…It is possible that these two regions of anomalously deep earthquakes may be the result of inaccuracies in the local velocity models used to locate the events, whereby significant differences in crustal structure could account for mislocated events. This is unlikely, however, since the northwest portion of the state is characterized 35 to 40 km thick crust (Brumbaugh, 1987) while the northeastern portion of the state is characterized by crust that is 40 km thick or more (Gilbert et al, 2007), and both regions likely possess similar upper crustal velocities due to their similar compositions. Further, earthquakes within both areas were located using the same crustal velocity model from Warren 1969 for the Colorado Plateau.…”

Section: Discussion Our New Arizona Earthquake Catalog Is Consistentmentioning

confidence: 99%

“…(Figure 13). Characteristics including crustal structure and thickness, stress orientations, volcanism, seismicity, heat flow, and gravity suggest that the Transition Zone represents both a tectonic and geophysical transition between the thick and relatively stable crust of the Colorado Plateau and the thin and highly-extended crust of the southern Basin and Range (Brumbaugh, 1987;Hendricks and Plescia, 1991;Thompson and Zoback, 1979).…”

Section: Chaptermentioning

confidence: 99%

“…First, the north-central portion of the state has been the most seismically active in terms of event frequency (Figure 3,left) and has produced the three largest historical earthquakes (m l 6.0-6.2), which were located near Flagstaff, Arizona. These data form the basis for the most recent seismic hazard analysis for Arizona (Figure 4), and coincide with the location of the Northern Arizona Seismic Belt (NASB), which has been proposed as the southwestern tectonic boundary of the Colorado Plateau (Brumbaugh, 1987). Several other areas are also characterized by relatively higher rates of historical seismicity.…”

Section: Introduction and Scope Of Workmentioning

confidence: 99%

“…The boundaries between these provinces are still debated and vary greatly when considering geologic and geophysical parameters (Pierce, 1984;Brumbaugh, 1987). The Colorado Plateau encompasses much of the northern and eastern portions of the state and is characterized by relatively thick (~40 km) crust that has experienced little deformation since the Mesozoic.…”

Section: Introduction and Scope Of Workmentioning

confidence: 99%

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Seismicity within Arizona during the Deployment of the EarthScope USArray Transportable Array

Lockridge¹,

Fouch²,

Arrowsmith³

2012

Bulletin of the Seismological Society of America

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i ABSTRACT The goal of this study is to gain a better understanding of earthquake distribution and regional tectonic structure across Arizona. To achieve this objective, I utilized seismic data from EarthScope's USArray Transportable Array (TA), which was deployed in Arizona from April 2006 to March 2009. With station spacing of approximately 70 km and ~3 years of continuous three-component broadband seismic data, the TA provided an unprecedented opportunity to develop the first seismicity catalog for Arizona without spatial sampling bias. In this study I developed a new data analysis workflow to detect smaller scale seismicity across a regional study area, which serves as a template for future regional analyses of TA data and similar datasets.The final event catalog produced for this study increased the total number of earthquakes documented in Arizona by more than 50% compared to the historical catalog, despite being generated from less than three years of continuous waveform data. I combined this new TA catalog with existing earthquake catalogs to construct a comprehensive historical earthquake catalog for Arizona. These results enabled the identification of several previously unidentified areas of seismic activity within the state, as well as two regions characterized by seismicity in the deeper (>20 km) crust. The catalog also includes 16 event clusters, 10 of which exhibited clear temporal clustering and swarm-like behavior. These swarms were distributed throughout all three physiographic provinces, suggesting that earthquake swarms occur regardless of tectonic or physiographic setting. I also conducted a case study for an earthquake swarm in June of 2007 near Theodore Roosevelt Lake, approximately 80 miles northeast of Phoenix. Families of events showed very ii similar character, suggesting a nearly identical source location and focal mechanism. We obtained focal mechanisms for the largest of these events, and found that they are consistent with normal faulting, expected in this area of the Arizona Transition Zone. Further, I observed no notable correlation between reservoir water level and seismicity. The occurrence of multiple historical earthquakes in the areas surrounding the reservoir indicates that this swarm was likely the result of tectonic strain release, and not reservoir induced seismicity.iii ACKNOWLEDGMENTS

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Section: Discussion Our New Arizona Earthquake Catalog Is Consistentmentioning

confidence: 99%

Section: Chaptermentioning

confidence: 99%

Section: Introduction and Scope Of Workmentioning

confidence: 99%

Section: Introduction and Scope Of Workmentioning

confidence: 99%

See 2 more Smart Citations

Seismicity within Arizona during the Deployment of the EarthScope USArray Transportable Array

Lockridge¹,

Fouch²,

Arrowsmith³

2012

Bulletin of the Seismological Society of America

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“…Geophysical models of the Colorado Plateau/Basin and Range transition show a significant decrease in depth to the mantle from approximately 40 km in the interior of the plateau to 22 km in the Basin and Range (Brumbaugh, 1987).…”

Section: Distribution Of Volcanic Centers In Cinder Cone Fieldsmentioning

confidence: 99%

Vent alignments in San Francisco volcanic field, Arizona : statistical analysis and assessment of structural controls

Chen¹

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Lower crustal evolution under central Arizona: Sr, Nd and Pb isotopic and geochemical evidence from the mafic xenoliths of Camp Creek

Esperança

Carlson

Shirey

1988

Earth and Planetary Science Letters

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A tectonic boundary for the southern Colorado plateau

Cited by 18 publications

References 9 publications

Seismicity within Arizona during the Deployment of the EarthScope USArray Transportable Array

Seismicity within Arizona during the Deployment of the EarthScope USArray Transportable Array

Vent alignments in San Francisco volcanic field, Arizona : statistical analysis and assessment of structural controls

Lower crustal evolution under central Arizona: Sr, Nd and Pb isotopic and geochemical evidence from the mafic xenoliths of Camp Creek

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