Present‐Day and Long‐Term Uplift Across the Western Transverse Ranges of Southern California

2020 ◽  
Vol 125 (8) ◽  
Author(s):  
K. M. Johnson ◽  
W. C. Hammond ◽  
R. J. Burgette ◽  
S. T. Marshall ◽  
C. C. Sorlien
Keyword(s):  
Southern California ◽  
Transverse Ranges

Present-day and Long-term Uplift Across the Western Transverse Ranges of Southern California

2020 ◽  
Author(s):  
Kaj M. Johnson ◽  
William Charles Hammond ◽  
Reed J. Burgette ◽  
Scott T. Marshall ◽  
Christopher Clarke Sorlien
Keyword(s):  
Southern California ◽  
Transverse Ranges

scholarly journals Growth Response of Bigcone Douglas Fir (Pseudotsuga macrocarpa) to Long-Term Ozone Exposure in Southern California

1995 ◽  
Vol 45 (1) ◽  
pp. 36-45 ◽  
Author(s):  
David L. Peterson ◽  
David G. Silsbee ◽  
Mark Poth ◽  
Michael J. Arbaugh ◽  
Frances E. Biles
Keyword(s):  
Southern California ◽  
Growth Response ◽  
Douglas Fir ◽  
Ozone Exposure

Quaternary chronology and rock uplift recorded by marine terraces, Gaviota coast, Santa Barbara County, California, USA

2021 ◽  
Author(s):  
Daniel L. Morel ◽  
Kristin D. Morell ◽  
Edward A. Keller ◽  
Tammy M. Rittenour
Keyword(s):  
Southern California ◽  
Seismic Hazard Assessment ◽  
Fault System ◽  
The South ◽  
Tectonic Model ◽  
Transverse Ranges ◽  
Marine Terraces ◽  
Uplift Rates ◽  
Regional Tectonic ◽  
Source Models

The Transverse Ranges of southern California are a region of active transpression on the western margin of North America that hosts some of the world’s highest uplift rates at the Ventura anticline. Yet, the manner in which rock uplift rates change along strike from Ventura to the westernmost Transverse Ranges and the structures that may be responsible for this uplift remain unclear. Here, we quantified rock uplift rates within the westernmost 60 km of the Transverse Ranges by obtaining new age constraints from raised beach and shoreface deposits from marine terraces along the Gaviota coast. Twelve radiocarbon (seven sites) and eight luminescence (six sites) ages, ranging from ca. 50 to 40 k.y. B.P. and ca. 56 to 43 ka, respectively, consistently suggest that the first emergent terrace dates to marine isotope stage (MIS) 3, rather than MIS 5a as previously reported for the western Gaviota coast. These younger ages yield rock uplift rates between 0.8 ± 0.3 and 1.8 ± 0.4 m/k.y., i.e., over five times higher than previous estimates for this region. The spatial distribution of rock uplift rates and the abrupt along-strike changes in marine terrace elevations favor a regional tectonic model with a step-wise change in rock uplift across the south branch of the Santa Ynez fault. The south branch of the Santa Ynez fault appears to separate two regional tectonic blocks, characterized by rock uplift rates of ∼1.3−1.6 m/k.y. to the east and slightly lower rates to the west (∼0.8−1.4 m/k.y.). Our observations suggest that coastal rock uplift is primarily accommodated by deeply rooted far-field structures such as the offshore Pitas Point−North Channel fault system and the Santa Ynez fault, and that smaller through-going structures impart second-order controls and locally accommodate short-wavelength (<10-km-long strike length) deformation. These results imply that although the rates of rock uplift decline westward along strike, the westernmost portion of the western Transverse Ranges nonetheless accommodates relatively high (>1 m/k.y.) rock uplift rates at a significant distance (>50 km) from the rapidly uplifting (6−7 m/k.y.) Ventura anticline, and >100 km from the prominent restraining bend (“Big Bend”) in the San Andreas fault. The new constraints on the geometry of Quaternary-active structures and regional rates of fault-related deformation have implications for regional earthquake source models and seismic hazard assessment in the highly populated southern California coast region.

scholarly journals Five-century record of climate and groundwater recharge variability in southern California

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
F. Manna ◽  
K. M. Walton ◽  
J. A. Cherry ◽  
B. L. Parker
Keyword(s):  
Los Angeles ◽  
Groundwater Recharge ◽  
Southern California ◽  
Surface Soil ◽  
Time Interval ◽  
Chloride Salt ◽  
Freshwater Flow ◽  
The Pacific ◽  
Salt Distribution

AbstractModifications to the rates of water flowing from the surface to groundwater (groundwater recharge) due to climate variability are the most difficult to assess because of the lack of direct long-term observations. Here, we analyze the chloride salt distribution below the surface soil on a plateau near Los Angeles to reconstruct the amount of recharge that occurred in the last five centuries. Over this time interval, periods of major high and low recharge with different duration follow each other and this cyclicity is consistent with long-term atmospheric forcing patterns, such as the Pacific Decadal Oscillation. This study determines the range and the natural variability of recharge to groundwater, which sustains local freshwater flow system, and helps forecast future availability of groundwater resource in southern California, where water scarcity is critical to both local and global populations.

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