scholarly journals Bayesian inverse estimation of urban CO2 emissions: Results from a synthetic data simulation over Salt Lake City, UT

Elem Sci Anth ◽  
2019 ◽  
Vol 7 ◽  
Author(s):  
Lewis Kunik ◽  
Derek V. Mallia ◽  
Kevin R. Gurney ◽  
Daniel L. Mendoza ◽  
Tomohiro Oda ◽  
...  
Keyword(s):  
Transport Model ◽  
Salt Lake ◽  
Salt Lake City ◽  
Synthetic Data ◽  
Emission Inventories ◽  
Model Data ◽  
Mismatch Error ◽  
Data Simulation ◽  
Salt Lake Valley ◽  
Lake City

Top-down, data-driven models possess ample power to improve the accuracy of bottom-up carbon dioxide (CO2) emission inventories, and more work is needed to explore the merger of top-down and bottom-up estimates to better inform the metrics used to monitor global CO2 fluxes. Here we present a Bayesian inverse modeling framework over Salt Lake City, Utah, which utilizes available CO2 emission inventories to establish a synthetic data simulation aimed at exploring model uncertainties. Prescribing a high-resolution, urban-scale data product (Hestia) as the “true” emissions in the model, we combine prior emissions with an atmospheric transport model to derive modeled afternoon CO2 enhancements at six monitoring sites within the Salt Lake Valley during the month of September 2015. A global high-resolution gridded emissions data product (ODIAC) is used as the prior, and objective uncertainty structures are defined for both the a priori estimates and the transport model-data relationship which consider non-negligible spatial and temporal covariances. Optimized (posterior) emissions over the Salt Lake Valley agree closely with the assumed “true” emissions during afternoon times, while results including unconstrained times (e.g. night-time) lack such agreement. Both spatial and temporal correlations of prior errors were found to be necessary for obtaining a robust posterior estimate. Model sensitivity analyses are performed, which examine correlation length and time scales, model-data mismatch error, and measurement site network variability. Through these analyses, one measurement site is identified as being particularly prone to introducing bias into posterior emissions due to influences from a nearby point source. Increasing model-data mismatch error at this site is shown to reduce bias in the posterior without significantly compromising agreement with monthly averaged true emissions.

The 18 March 2020 M 5.7 Magna, Utah, Earthquake: Strong-Motion Data and Implications for Seismic Hazard in the Salt Lake Valley

2021 ◽  
Author(s):  
Ivan Wong ◽  
Qimin Wu ◽  
James C. Pechmann
Keyword(s):  
Seismic Hazard ◽  
Fault Zone ◽  
Salt Lake ◽  
Salt Lake City ◽  
Strong Motion ◽  
Ground Shaking ◽  
Fault Segment ◽  
Salt Lake Valley ◽  
Lake City ◽  
Wasatch Fault

Abstract The 2020 oblique normal-faulting M 5.7 Magna mainshock has provided the best dataset of recorded strong ground motions for an earthquake within the Wasatch Front region, Utah, and the larger Basin and Range Province. We performed a preliminary evaluation of the strong motion and broadband data from this earthquake and compared the data with the Next Generation Attenuation - West2 Project (NGA-West2) ground-motion models (GMMs). The highest horizontal peak ground acceleration (PGA) recorded was 0.43g (geometric mean of the two horizontal components) at a station located above the rupture plane at a rupture distance of 8 km. Eleven stations recorded PGAs >0.20g. Most of these stations are located on the deep sedimentary deposits within the Salt Lake Valley, and all are at rupture distances <20  km. The data compare favorably with the NGA-West2 GMMs, although the expected variability was observed. PGAs exceed the GMM predictions at the closest distances for the source model that we used. The area of the strongest ground shaking encompassed the town of Magna, where some of the heaviest damage occurred. A significant implication of the 2020 Magna earthquake for seismic hazards in the Salt Lake Valley arises from the possibility that this earthquake occurred on the Salt Lake City segment of the Wasatch fault. If so, then the dip of this fault segment must decrease with depth to ≤30°–35°, as proposed by Pang et al. (2020)—at least along the northern part of the segment where the earthquake occurred. Because of the lack of information about the subsurface geometry of the Wasatch fault zone, modeling of this fault zone in seismic hazard analyses has assumed a moderate dip of 50°±15°. Assuming a more shallowly dipping fault results in higher estimates of ground shaking in future large earthquakes on this fault. Alternative interpretations of the Magna earthquake are that it occurred (1) on an auxiliary fault within the Wasatch fault zone or (2) on a listric section of the northern Salt Lake City segment that is not representative of the geometry of the whole fault segment.

A field trip to observe features of Lake Bonneville, mountain glaciation, and Great Salt Lake near Salt Lake City, Utah, USA

2021 ◽  
pp. 71-94
Author(s):  
Charles G. (Jack) Oviatt ◽  
Genevieve Atwood ◽  
Benjamin J.C. Laabs ◽  
Paul W. Jewell ◽  
Harry M. Jol
Keyword(s):  
Great Basin ◽  
Salt Lake ◽  
Great Salt Lake ◽  
Salt Lake City ◽  
Field Trip ◽  
Lake Bonneville ◽  
Salt Lake Valley ◽  
Mountain Glaciers ◽  
History Of ◽  
Lake City

ABSTRACT On this field trip we visit three sites in the Salt Lake Valley, Utah, USA, where we examine the geomorphology of the Bonneville shoreline, the history of glaciation in the Wasatch Range, and shorezone geomorphology of Great Salt Lake. Stop 1 is at Steep Mountain bench, adjacent to Point of the Mountain in the Traverse Mountains, where the Bonneville shoreline is well developed and we can examine geomorphic evidence for the behavior of Lake Bonneville at its highest levels. At Stop 2 at the mouths of Little Cottonwood and Bells Canyons in the Wasatch Range, we examine geochronologic and geomorphic evidence for the interaction of mountain glaciers with Lake Bonneville. At the Great Salt Lake at Stop 3, we can examine modern processes and evidence of the Holocene history of the lake, and appreciate how Lake Bonneville and Great Salt Lake are two end members of a long-lived lacustrine system in one of the tectonically generated basins of the Great Basin.

Slip vectors on faults near Salt Lake City, Utah, from quaternary displacements and seismicity

1980 ◽  
Vol 70 (5) ◽  
pp. 1521-1526
Author(s):  
Terry L. Pavlis ◽  
R. B. Smith
Keyword(s):  
Salt Lake ◽  
Salt Lake City ◽  
Basin And Range ◽  
Earthquake Hazards ◽  
Basin And Range Province ◽  
Fault Plane Solutions ◽  
Salt Lake Valley ◽  
Range Type ◽  
Major Fault ◽  
Lake City

abstract Slip vectors, derived from striations on variably oriented faults along the west and south sides of a bedrock spur north of Salt Lake City, Utah, indicate a consistent relative motion between the spur and the Salt Lake Valley during Quaternary time. The possibility of motion of coherent crustal blocks during basin and range type faulting suggests: (1) segmentation of major fault zones, such as the Wasatch fault zone, into independent crustal blocks, complicates the evaluation of earthquake hazards because of the unknown relationships between individual faults; and (2) if this pattern of crustal deformation is characteristic of the Basin and Range Province, then fault-plane solutions for this area should be carefully evaluated because they may reflect local displacements rather than the effects of the regional stress field.

scholarly journals Lake-Breeze Fronts in the Salt Lake Valley

2007 ◽  
Vol 46 (2) ◽  
pp. 196-211 ◽  
Author(s):  
Daniel E. Zumpfe ◽  
John D. Horel
Keyword(s):  
Salt Lake ◽  
Great Salt Lake ◽  
Vertical Mixing ◽  
Salt Lake City ◽  
Lake Breeze ◽  
Salt Lake Valley ◽  
The North ◽  
Dewpoint Temperature ◽  
Lake City ◽  
Transport And Mixing

Abstract Winds at the Salt Lake City International Airport (SLC) during the April–October period from 1948 to 2003 have been observed to shift to the north (up-valley direction) between late morning and afternoon on over 70% of the days without precipitation. Lake-breeze fronts that develop as a result of the differential heating between the air over the nearby Great Salt Lake and that over the lake’s surroundings are observed at SLC only a few times each month. Fewer lake-breeze fronts are observed during late July–early September than before or after that period. Interannual fluctuations in the areal extent of the shallow Great Salt Lake contribute to year-to-year variations in the number of lake-breeze frontal passages at SLC. Data collected during the Vertical Transport and Mixing Experiment (VTMX) of October 2000 are used to examine the structure and evolution of a lake-breeze front that moved through the Salt Lake Valley on 17 October. The onset of upslope and up-valley winds occurred within the valley prior to the passage of the lake-breeze front. The lake-breeze front moved at roughly 3 m s−1 up the valley and was characterized near the surface by an abrupt increase in wind speed and dewpoint temperature over a distance of 3–4 km. Rapid vertical mixing of aerosols at the top of the 600–800-m-deep boundary layer was evident as the front passed.

Lateral Spread Hazard Mapping of the Northern Salt Lake Valley, Utah, for a M7.0 Scenario Earthquake

2007 ◽  
Vol 23 (1) ◽  
pp. 95-113 ◽  
Author(s):  
Michael J. Olsen ◽  
Steven F. Bartlett ◽  
Barry J. Solomon
Keyword(s):  
Salt Lake ◽  
Salt Lake City ◽  
Lateral Spread ◽  
Hazard Mapping ◽  
Alluvial Deposits ◽  
Salt Lake Valley ◽  
High Hazard ◽  
Lake City ◽  
Moderate Hazard ◽  
Wasatch Fault

This paper describes the methodology used to develop a lateral spread-displacement hazard map for northern Salt Lake Valley, Utah, using a scenario M7.0 earthquake occurring on the Salt Lake City segment of the Wasatch fault. The mapping effort is supported by a substantial amount of geotechnical, geologic, and topographic data compiled for the Salt Lake Valley, Utah. ArcGIS® routines created for the mapping project then input this information to perform site-specific lateral spread analyses using methods developed by Bartlett and Youd (1992) and Youd et. al. (2002) at individual borehole locations. The distributions of predicted lateral spread displacements from the boreholes located spatially within a geologic unit were subsequently used to map the hazard for that particular unit. The mapped displacement zones consist of low hazard (0–0.1 m), moderate hazard (0.1–0.3 m), high hazard (0.3–1.0 m), and very high hazard (>1.0 m). As expected, the produced map shows the highest hazard in the alluvial deposits at the center of the valley and in sandy deposits close to the fault. This mapping effort is currently being applied to the southern part of the Salt Lake Valley, Utah, and probabilistic maps are being developed for the entire valley.

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