The Salton Sea, situated in the Lower Colorado River Basin (LCRB), is under duress due to, among other things, increased water demands of cities like San Diego, California and Mexicali, Mexico. This research developed a tool to investigate the implications of water transfers on the health and sustainability of the Salton Sea Ecosystem. The Salton Sea model is a spatially-explicit, stochastic, simulation model representing water flow, i.e., water volume and quantity of Total Dissolved Salts (TDS) and Phosphorus (P), in the LCRB as it enters the Salton Sea. The model is formulated as a compartment model based on difference equations with a daily time step using STELLA® 8.0 software. The model was developed, evaluated, and applied to simulate the potential effects on the population dynamics of selected fish and avian species at the Salton Sea under six different scenarios. Oneway ANOVAs and Bonferroni Multiple Comparison Post Hoc Tests were performed for the water management scenarios and selected variables involving the fish and bird population dynamics using SPSS version 12.0.1 (SPSS Inc., 2003). Weather station daily data were collected for both precipitation and Eto for a 25- year period (1980-2004) for the Salton Sea area. Thirty-four probability distributions were fit to the monthly datasets. Monthly distributions were used to preserve seasonality when modeling future climate scenarios. Additionally, binomial and multinomial logistic regression models were utilized to determine the relationships concerning precipitation events and Eto levels. Further, two strategies were employed in modeling the uncertainty in future climate patterns, namely deterministic and stochastic versions of the driving variables. A climate sensitivity analysis was also conducted and results showed that the cumulative effects and change of plus or minus 10 percent in Salton Sea inflows can have significant effects on sea elevation and salinity. Both of the Salton Sea impoundment scenarios significantly (P<0.05) lowered the salinity in the north or main sea impoundments compared to future downward trends in sea elevation and upward trends in salinity under baseline conditions. Further, the elevations of the north or main sea impoundments were stabilized at -220 by the end of 2024. Should action be taken to stabilize the sea and reduce salinity, the impoundment scenarios demonstrated the most success in the present study. If no such action is taken, the simulation results demonstrate that the current community dynamics of the Salton Sea will be further impaired as a result.

Thesis (Ph. D.)--University of Chicago, 1912. / Plate 13-14 each preceded by leaf with descriptive letter press. [Reprinted from Publication 193 of the Carnegie institution of Washington].

Thesis (M.S.)--San Diego State University, 1994. / Includes bibliographical references (leaves 69-75).

Thesis (Ph. D.)--University of Chicago, 1912. / Plate 13-14 each preceded by leaf with descriptive letter press. [Reprinted from Publication 193 of the Carnegie institution of Washington]. Also available on the Internet. Also issued online.

We examine the structural complexities of a 28-km long part of the Clark fault of the San Jacinto fault zone in southern California in order to better document its lateral extent and the style of deformation of its southeast end. Changes in structural style are observed as the Clark fault’s damage zone widens from ~ 1-2 km in crystalline rocks of the Peninsular Ranges southeastward to ~ 18 km in the sedimentary rocks of the San Felipe-Borrego subbasin of the Salton Trough. The Clark fault extends into the San Felipe-Borrego subbasin as the Arroyo Salada segment for ~ 11-12 km to a newly defined northeast-trending structural boundary. This structural boundary, referred to herein as the Pumpkin Crossing block, is a ~ 3-km wide and ~ 8-km long fault zone dominated by northeast-striking sinistral-normal strike-slip faults. Southeast of the Pumpkin Crossing block the newly defined San Felipe Hills segment extends the Clark fault another ~12-13 km southeast to its intersection with the Extra fault zone. The Clark fault may have nearly 14.5-18 km of right separation represented in the surface deformation of the Arroyo Salada and San Felipe Hills segments, but the total amount of strain is masked by the wide diffuse fault zone with its complex deformation patterns and geometries. The lateral change observed in microseismicity patterns across the Arroyo Salada and San Felipe Hills segment boundary supports our structural interpretations about the existence, location, and structure of this boundary. Vertical patterns in the microseismicity suggest that the Clark fault zone narrows at depth, dips steeply northeast in the subsurface, and must interact with at least one weak decollement layer(s) beneath and/or with the sedimentary basin. Structural deformation within the late Miocene to Holocene silty- and clay-rich sedimentary basin of the Salton Trough includes features characteristic of strike-slip faults, such as stepovers, conjugate faults, folds, flower structures, and fault bends, as well as many unique structures that include pooch structures, ramp-flat geometries of strike-slip faults, complex en echelon fault zones with localized shear distributed across a high frequency network of faults, and heterogeneous kinematic indicators within individual fault zones.

The southern - 100 km long Coachella section of the San Andreas fault is the only section of the fault in southern California that has not experienced a historical earthquake, and it may be the most overdue section of the fault. Numerical models of rupture propagation shows that a large earthquake with a nucleation one in the Durmid Hill field area would produce particularly destructive and deadly ground shaking in southern California. This is used as the model earthquake for the ShakeOut exercises in southern California because it is may represent the worst-case scenario for southern California but does not appear to be a very likely scenario following this research. Building on existing geologic mapping that shows major Pleistocene to Holocene contraction near the hypothesized nucleation, we use geologic mapping to develop and validate a competing geometric and kinematic model for the southern tip of the San Andreas Fault. A ladder-like-fault model explains the widespread contraction in the Durmid Hill study area as the result of contraction between the main strand of the San Andreas fault and East Shoreline strand. The East Shoreline strand of the San Andreas fault is the newly discovered fault and is dispersed across a zone between 0.5 to 1 km wide, and encompasses an area on the northeast shore of the Salton Sea. There is persistent and strong contraction across the entire - 1.5 to 3.5 km wide San Andreas fault zone because both dextral "side-rail" faults are counterclockwise, and in a contractional bend, relative to current plate motions. This contractional bend was previously documented for the main strand of San Andreas fault. A new digital geologic map and field studies document the stratigraphy and structures at a range of scales between Bombay Beach and Salt Creek. Numerous folds, narrow strike-slip and oblique-slip faults, and sheared damaged rocks in latest Miocene (?) to Holocene sediment lie within the wide and very complex damage zone of the main strand of the San Andreas fault zone. The East Shoreline strand of the San Andreas fault system buffers the main strand from major stress changes produced by deformation along the sinistral to sinistral-normal Extra fault array under the Salton Sea.

We examine the structural complexities of a 28-km long part of the Clark fault of the San Jacinto fault zone in southern California in order to better document its lateral extent and the style of deformation of its southeast end. Changes in structural style are observed as the Clark fault’s damage zone widens from ~ 1-2 km in crystalline rocks of the Peninsular Ranges southeastward to ~ 18 km in the sedimentary rocks of the San Felipe-Borrego subbasin of the Salton Trough. The Clark fault extends into the San Felipe-Borrego subbasin as the Arroyo Salada segment for ~ 11-12 km to a newly defined northeast-trending structural boundary. This structural boundary, referred to herein as the Pumpkin Crossing block, is a ~ 3-km wide and ~ 8-km long fault zone dominated by northeast-striking sinistral-normal strike-slip faults. Southeast of the Pumpkin Crossing block the newly defined San Felipe Hills segment extends the Clark fault another ~12-13 km southeast to its intersection with the Extra fault zone. The Clark fault may have nearly 14.5-18 km of right separation represented in the surface deformation of the Arroyo Salada and San Felipe Hills segments, but the total amount of strain is masked by the wide diffuse fault zone with its complex deformation patterns and geometries. The lateral change observed in microseismicity patterns across the Arroyo Salada and San Felipe Hills segment boundary supports our structural interpretations about the existence, location, and structure of this boundary. Vertical patterns in the microseismicity suggest that the Clark fault zone narrows at depth, dips steeply northeast in the subsurface, and must interact with at least one weak decollement layer(s) beneath and/or with the sedimentary basin. Structural deformation within the late Miocene to Holocene silty- and clay-rich sedimentary basin of the Salton Trough includes features characteristic of strike-slip faults, such as stepovers, conjugate faults, folds, flower structures, and fault bends, as well as many unique structures that include pooch structures, ramp-flat geometries of strike-slip faults, complex en echelon fault zones with localized shear distributed across a high frequency network of faults, and heterogeneous kinematic indicators within individual fault zones.

Field studies in the southwest Salton Trough between Yaqui Ridge and Borrego Mountain show that the West Salton detachment fault was active during the Pliocene and may have initiated during the latest Miocene. At Yaqui Ridge dominantly east-directed extension is recorded by slickenlines on the NW-striking detachment fault, and shows that the fault is actually a low-angle dextral oblique strike-slip fault. Crustal inheritance is responsible for the position of the fault at Yaqui Ridge, which reactivates a late Cretaceous reverse -sense mylonite zone at map scale. Late Miocene to Pliocene basin fill deposits at Borrego Mountain display progressive unconformities, contain detritus shed from the footwall and damage zone of the West Salton detachment fault, record the growth of a large hanging wall anticline, and document the initiation and evolution of the West Salton detachment fault. The Borrego Mountain anticline is a major hanging wall growth fold that trends - N60 °W and has at least 420 m of structural relief. The late Quaternary Sunset conglomerate is - 600 m thick, lies in angular unconformity on Pliocene basin fill, is bound on the SW by the dextral oblique Sunset fault, and coarsens upward and SW toward the fault. It is dominated by plutonic lithologies from nearby areas, contains up to 10% recycled sandstone clasts from Pliocene deposits, and was shed from the SW side of the then-active Sunset fault. Based on lithologic, stratigraphic, compositional similarities, we correlate this conglomerate to part of the - 1. I - 0.6 Ma Ocotillo Formation. The West Salton detachment fault was folded and deactivated at Yaqui Ridge by the dextral oblique San Felipe fault zone starting - 1. l - 1.3 Ma. The Sunset fault is in the middle of a complex left stepover between the San Felipe fault to the NW and the Fish Creek Mountains fault to the SE. Structural analyses and mapping show that syntec tonic conglomerate, the West Salton detachment fault, and footwall crystalline rocks all have similar fold geometries and record similar amounts of NE-SW shortening. The dominant SE-trending population of slip vectors on the Sunset fault is not present on the West Salton detachment fault and suggests limited or no activation of the older detachment fault by the younger fault zone.

This research attempted to uncover the sociopolitical ideologies, ethnic discrimination, and class oppression that create sustained social dominance through resource control in the unicorporated community of the Salton Sea located in Eastern Riverside County, California in regard to public transportation issues.

In the middle of the California Desert is an inland desert sea, called the Salton Sea. Its existence is curious, nearly magical. It is California’s largest lake, it is saltier than the Pacific Ocean, it is slowly dying, and its existence is a complete accident. This thesis breaks down the historical narrative of the Salton Sea from a white settler perspective, using theories posed by Yi Fu Tuan about distinctions between space and place. The temporality of spatial locations, the construction of the binaries natural/built, and the moralizing of landscapes all provide further understanding of the Salton Sea’s existence. Throughout history, the white settlers of the Imperial Desert have projected, their morals and desires upon the desert landscape, reforming the space into their vision of the future as a result of their abilities to tame and control rivers. Instead of a future, they produced a place replete with the past: a place considered worthless and potentially dangerous. Through looking at the constructions of space, place, memory, and history, we are better able to understand the birth of this desert sea.