scholarly journals Upper Pleistocene and Holocene Storm Deposits Eroded from the Granodiorite Coast on Isla San Diego (Baja California Sur, Mexico)

2021 ◽  
Vol 9 (5) ◽  
pp. 555
Author(s):  
Ginni Callahan ◽  
Markes E. Johnson ◽  
Rigoberto Guardado-France ◽  
Jorge Ledesma-Vázquez
Keyword(s):  
Late Pleistocene ◽  
Gulf Of California ◽  
San Diego ◽  
Historical Record ◽  
Three Dimensions ◽  
Marine Biota ◽  
Hurricane Wind ◽  
Submarine Ridge ◽  
Individual Wave ◽  
Wave Heights

This project examines the role of hurricane-strength events likely to have exceeded 119 km/h in wind speed that entered the Gulf of California from the open Pacific Ocean during Late Pleistocene and Holocene times to impact the granodiorite shoreline on Isla San Diego. Conglomerate dominated by large, ellipsoidal to subspherical boulders at the islands south end were canvassed at six stations. A total of 200 individual cobbles and boulders were systematically measured in three dimensions, providing the database for analyses of variations in clast shape and size. The project’s goal was to apply mathematical equations elaborated after Nott (2003) with subsequent refinements to estimate individual wave heights necessary to lift igneous blocks from the joint-bound and exfoliated coast on Isla San Diego. On average, wave heights on the order of 3 m are calculated as having impacted the Late Pleistocene rocky coastline on Isla San Diego during storms, although the largest boulders more than a meter in diameter are estimated to weigh two metric tons and would have required waves in excess of 10 m for extraction. Described for the first time, a fossil marine biota associated with the boulder beds confirms a littoral-to-very-shallow water setting correlated with Marine Isotope Substage 5e approximately 125,000 years ago. A narrow submarine ridge consisting, in part, of loose cobbles and boulders extends for 1.4 km to the southwest from the island’s tip, suggesting that Holocene storms continued to transport rock debris removed from the shore. The historical record of events registered on the Saffir–Simpson Hurricane Wind Scale in the Gulf of California suggests that major storms with the same intensity struck the island in earlier times.

scholarly journals Late Pleistocene Boulder Slumps Eroded from a Basalt Shoreline at El Confital Beach on Gran Canaria (Canary Islands, Spain)

2021 ◽  
Vol 9 (2) ◽  
pp. 138
Author(s):  
Inés Galindo ◽  
Markes E. Johnson ◽  
Esther Martín-González ◽  
Carmen Romero ◽  
Juana Vegas ◽  
...  
Keyword(s):  
Late Pleistocene ◽  
Historical Record ◽  
Three Dimensions ◽  
Marine Biota ◽  
Gran Canaria ◽  
Basaltic Rocks ◽  
Individual Wave ◽  
Wave Heights ◽  
Scientific Value ◽  
The Impact

This study examines the role of North Atlantic storms degrading a Late Pleistocene rocky shoreline formed by basaltic rocks overlying hyaloclastite rocks on a small volcanic peninsula connected to Gran Canaria in the central region of the Canary Archipelago. A conglomerate dominated by large, ellipsoidal to angular boulders eroded from an adjacent basalt flow was canvassed at six stations distributed along 800 m of the modern shore at El Confital, on the outskirts of Las Palmas de Gran Canaria. A total of 166 individual basalt cobbles and boulders were systematically measured in three dimensions, providing the database for analyses of variations in clast shape and size. The goal of this study was to apply mathematical equations elaborated after Nott (2003) and subsequent refinements in order to estimate individual wave heights necessary to lift basalt blocks from the layered and joint-bound sea cliffs at El Confital. On average, wave heights in the order of 4.2 to 4.5 m are calculated as having impacted the Late Pleistocene rocky coastline at El Confital, although the largest boulders in excess of 2 m in diameter would have required larger waves for extraction. A review of the fossil marine biota associated with the boulder beds confirms a littoral to very shallow water setting correlated in time with Marine Isotope Stage 5e (Eemian Stage) approximately 125,000 years ago. The historical record of major storms in the regions of the Canary and Azorean islands indicates that events of hurricane strength were likely to have struck El Confital in earlier times. Due to its high scientific value, the outcrop area featured in this study is included in the Spanish Inventory of Geosites and must be properly protected and managed to ensure conservation against the impact of climate change foreseen in coming years.

scholarly journals An exceptionally preserved conulariid from Ordovician erratics of Northern European Lowlands

PalZ ◽  
2021 ◽  
Author(s):  
Consuelo Sendino ◽  
Martin M. Bochmann
Keyword(s):  
Internal Structure ◽  
Late Pleistocene ◽  
Point Of View ◽  
Three Dimensions ◽  
Northern European ◽  
Current Location ◽  
Transport Direction ◽  
First Time ◽  
Erratic Boulder

AbstractA conulariid preserved in three dimensions from Ordovician fluvioglacial erratics of the Northern European Lowlands (North German Plain) is described under open nomenclature. It is assigned to the genus Conularia with similarities to Baltoscandian conulariids. The lithology of the erratic boulder and fauna contained in it provide important information on the origin and transport direction of the sediment preserved in a kame from the Saalian glaciation. This paper deals with the site of origin of the boulder in Baltoscandia analysing the comprised palaeofauna, from a palaeostratigraphic and palaeogeographic point of view, from its deposition in Ordovician times until its arrival at its current location in the Late Pleistocene. It also reveals for the first time the internal structure of the conulariid aperture.

Holocene–late Pleistocene non-tropical carbonate sediments and tectonic history of the western rift basin margin of the southern Gulf of California

2001 ◽  
Vol 144 (1-2) ◽  
pp. 149-178 ◽  
Author(s):  
Jochen Halfar ◽  
Lucio Godinez-Orta ◽  
Glenn A. Goodfriend ◽  
David A. Mucciarone ◽  
James C. Ingle ◽  
...  
Keyword(s):  
Late Pleistocene ◽  
Gulf Of California ◽  
Rift Basin ◽  
Carbonate Sediments ◽  
Tectonic History ◽  
History Of ◽  
Basin Margin

Measured Metocean Characteristics of Gulf of Mexico Hurricanes

2015 ◽  
Author(s):  
George Z. Forristall ◽  
Jason McConochie
Keyword(s):  
Gulf Of Mexico ◽  
Wave Height ◽  
Storm Track ◽  
Significant Wave ◽  
Wind Speeds ◽  
Hurricane Wind ◽  
Wave Parameters ◽  
Wave Heights ◽  
Significant Wave Heights ◽  
Buoy Data

A wealth of Gulf of Mexico hurricane wind and wave data has been measured in recent years. We have constructed a database that combines HURDAT storm track information with NDBC buoy data for the years 1978–2010. HURDAT contains 141 storms for that period of which 67 had measured significant wave heights greater than 5 m. Industry measurements in Hurricanes Camille, Lili, Ivan, Katrina, Rita, Gustav and Ike have been added to the buoy data. We have used this data base to study the relationships between wind and wave parameters in hurricanes. Specifically, we have calculated regressions and equal probability contours for significant wave height and peak spectral periods, first and second moment periods, wave height and Jonswap gamma values, wind speeds and wave heights, and wave and wind directions. All of these calculations have been done for azimuthal quadrants of the storm and radial distances near and far from the storm center.

Earliest Utilization of Chicken in Upper California: The Zooarchaeology of Avian Remains from the San Diego Royal Presidio

2020 ◽  
Vol 85 (3) ◽  
pp. 516-534
Author(s):  
Aharon Sasson ◽  
Susan Arter
Keyword(s):  
San Diego ◽  
Egg Production ◽  
Mammalian Species ◽  
Body Part ◽  
Historical Record ◽  
Small Scale ◽  
Poultry Production ◽  
Medullary Bone ◽  
Standard Size ◽  
Wide Range

The San Diego Presidio, established in AD 1769, was the first European settlement in Upper California. Very little is known about chicken husbandry in colonial America, which makes this study the first comprehensive analysis of chicken remains in North America. Chickens are scarcely mentioned in historical accounts describing early California, and information on their sex, age, or management is rare. The faunal assemblage from the San Diego Presidio yielded 20 avian and 14 mammalian species. Chicken remains were studied through a wide range of zooarchaeological methods, including taphonomy, biometry, medullary bone, epiphyseal fusion, butchering, and body-part representation. Taphonomic analysis indicates good preservation of the bone assemblage. The biometric study points to two breeds of chickens: a smaller (bantam) breed alongside a standard-size chicken. The percentage of juvenile chickens (23%), the rooster/hen ratio (1:8.5), and high proportion of medullary bone point to on-site chicken husbandry focusing on meat and egg production. The historical record suggests that California presidios were not self-sufficient and that they relied on food provisioned from Mexico and nearby missions. We argue that small-scale poultry production, likely managed by women and children, provided California presidios with a form of subsistence independence.

scholarly journals EXTREME WAVE PARAMETERS BASED ON CONTINENTAL SHELF STORM WAVE RECORDS

1976 ◽  
Vol 1 (15) ◽  
pp. 9 ◽  
Author(s):  
R.E. Haring ◽  
A.R. Osborne ◽  
L.P. Spencer
Keyword(s):  
Continental Shelf ◽  
Rayleigh Distribution ◽  
Probability Level ◽  
Extreme Wave ◽  
Spectral Parameters ◽  
Wave Parameters ◽  
Individual Wave ◽  
Storm Wave ◽  
Surface Deviation ◽  
Wave Heights

Measured storm wave records from several Continental Shelf areas were used to test the adequacy of estimating formulae for individual wave parameters. In all, 376 hours of storm wave records were analyzed, and their properties nondimensionalized by fundamental spectral parameters. Results are presented for surface deviation statistics, individual wave height statistics and individual wave period statistics. The results can be used by ocean engineers to eliminate unintended bias from wave parameters selected for the design of offshore facilities. The most significant result is that measured rare wave heights in the storm wave records are on the order of 10 percent less than predicted by the Rayleigh distribution at the 1 in 1000 probability level.

The Making (and Unmaking) of a Bordered Imaginary

2021 ◽  
pp. 41-76
Author(s):  
Kristen Hill Maher ◽  
David Carruthers
Keyword(s):  
Industrial Production ◽  
San Diego ◽  
Local Level ◽  
Three Dimensions ◽  
Final Part ◽  
Large Role ◽  
The Us ◽  
The Asymmetry ◽  
International Border ◽  
Over Time

How has the notion of a line marking San Diego and Tijuana as unequal neighbors been produced and challenged over time? This chapter examines three dimensions of regional history. The first lays out the histories of tourism and commerce that developed out of the asymmetry of the international border. These sectors thrived on a border that was fluid yet premised on inequality. The second part focuses on industrial production and trade, sectors that both reinforced and blurred borders. The final part turns to the US government’s hardening of the borderline through policing and inspections, which have played a large role in making the asymmetric border psychologically “real.” Bordering practices also appear at the local level, as do many debordering challenges to the notion of a line demarking unequal places.

scholarly journals On Estimating Hurricane Return Periods

2010 ◽  
Vol 49 (5) ◽  
pp. 837-844 ◽  
Author(s):  
Kerry Emanuel ◽  
Thomas Jagger
Keyword(s):  
Threshold Model ◽  
Historical Record ◽  
Value Theory ◽  
Open Ocean ◽  
Distribution Functions ◽  
Return Periods ◽  
Modest Improvement ◽  
Wind Speeds ◽  
Hurricane Wind

Abstract Interest in hurricane risk usually focuses on landfalling events of the highest intensity, which cause a disproportionate amount of hurricane-related damage. Yet assessing the long-term risk of the most intense landfalling events is problematic because there are comparatively few of them in the historical record. For this reason, return periods of the most intense storms are usually estimated by first fitting standard probability distribution functions to records of lower-intensity events and then using such fits to estimate the high-intensity tails of the distributions. Here the authors attempt a modest improvement over this technique by making use of the much larger set of open-ocean hurricane records and postulating that hurricanes make landfall during a random stage of their open-ocean lifetime. After testing the validity of this assumption, an expression is derived for the probability density of maximum winds. The probability functions so derived are then used to estimate hurricane return periods for several highly populated regions, and these are compared with return periods calculated both from historical data and from a set of synthetic storms generated using a recently published downscaling technique. The resulting return-period distributions compare well to those estimated from extreme-value theory with parameter fitting using a peaks-over-threshold model, but they are valid over the whole range of hurricane wind speeds.

Analyses of Extreme Wave Heights in the Gulf of Mexico for Offshore Engineering Applications

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
Vijay Panchang ◽  
Chan Kwon Jeong ◽  
Zeki Demirbilek
Keyword(s):  
Gulf Of Mexico ◽  
Oil And Gas ◽  
American Petroleum Institute ◽  
Maximum Increase ◽  
Statistical Measures ◽  
Individual Wave ◽  
Wave Heights ◽  
Offshore Oil And Gas ◽  
Wave Models ◽  
Offshore Oil

The 2004–2008 hurricane season in the Gulf of Mexico (GOM) saw several exceedances of what was regarded, prior to that period, as the 100-year significant wave heights (SWHs) that are used for the design of offshore oil and gas facilities. As a result, these facilities sustained considerable damage and disrupted U.S. energy supplies. The wave climatology in the GOM is therefore studied in detail. A 51-year database of SWHs was constructed by using a combination of wind and wave models, and both individual wave heights and statistical measures were validated, to the extent possible, using buoy data. Analyses of the modeled data show that there is an increasing trend in the annual maximum SWHs in the eastern part of the GOM; the maximum trend is approximately 5.6 cm/year, which is of the same magnitude as that reported for the U.S. west coast. The western part; on the other hand, shows a decreasing trend. The maximum estimated 100-year SWHs (denoted by SWH100) are 19.1 m, 22.6 m and 26.7 m for the Gumbel, Weibull, and the GEV distributions, respectively. The estimates obtained here using the Weibull distribution are comparable to those obtained independently by API (API—American Petroleum Institute, 2007, “Interim Guidance on Hurricane Conditions in the Gulf of Mexico,” API Bulletin No. 2INT-MET). However, the use of objective criteria to identify the optimal distribution suggests that the GEV estimates are to be preferred if the engineer wishes to emphasize the upper tail where extremes are likely to occur. The maximum increase in the SWH100 due to the 2004–2008 season is of the order of 0.9 m to 2.7 m (depending as the distribution). Information generated here is intended to supplement the design recommendations provided by API (American Petroleum Institute, 2007, “Interim Guidance on Hurricane Conditions in the Gulf of Mexico,” API Bulletin No. 2INT-MET).

How Should We Combine Long and Short Term Wave Height Distributions?

2008 ◽  
Author(s):  
George Z. Forristall
Keyword(s):  
Time Series ◽  
Extreme Value Distribution ◽  
Ocean Engineering ◽  
Short Term ◽  
Method Of Calculation ◽  
Individual Wave ◽  
Long Time ◽  
Wave Heights ◽  
The Individual

Estimating the maximum wave or crest height that will occur in a long return interval is one of the fundamental problems for ocean engineers. Long time series of individual wave heights are not available. The calculations must start with measured or hindcast time series of significant wave heights. An extreme value distribution is fit to that data. The resulting long term distribution is then combined with a short term distribution for the individual heights. This study is concerned with finding the most accurate methods for that calculation. The basic tool is the Borgman integral, but it has been applied in many different ways. Theoretical derivations do not clearly indicate which method is most accurate, and time series of measurements long enough for accurate tests do not exist. These problems were circumvented in this study by constructing very long simulated time series with known distributions. Both initial value and storm based methods were tested. The correct method of calculation depends on what question is being asked. The distribution of the maximum wave heights in a six hour interval is different than the distribution of the maxima of all of the waves. The distribution of the maxima in a storm is different than the distribution of the maxima in an interval. We believe that the finding the maximum in a storm is the most appropriate question for ocean engineering design. The Tromans and Vanderschuren (1995, Proc. Offshore Tech. Conf., OTC 7683) method accurately matches the results from our storm simulations.

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