Contaminants still high in top-level carnivores in the Southern California Bight: levels of DDT and PCBs in resident and transient pinnipeds

Highly industrialized areas, such as the Southern California Bight, often have high levels of contaminants in marine sediments, which can cause chronic exposure to organisms long after their use has ceased. tDDT and tPCB were analyzed in the blubber of 145 stranded pinnipeds that died at local marine mammal centers between 1994 and 2006. Resident species (California sea lion and Pacific harbor seal) had significantly higher concentrations of tDDT and tPCB than the transient species (northern elephant seal). Adult female California sea lions had significantly lower concentrations of tDDT and tPCB than pups, yearlings, and adult males. Concentrations of both tDDT and tPCB in California sea lions significantly declined over time, but did not change in northern elephant seals. Current concentrations of tDDT and tPCB in California sea lions and harbor seals are among the highest values reported worldwide for marine mammals and exceed those reported to cause adverse health effects.     

The occurrence of trigger effects in regional seismicity

This study is concerned with the influence exerted by worldwide M ≥ 7.5 earthquakes on the seismicity of California, and well as with the effects of M ≥ 5 southern California earthquakes on northern Californian seismicity. The analysis concerns the 1990–2013 period. We noted a seismicity increase in southern and northern California during the first 24 hours after worldwide earthquakes and a decrease during the next 48 hours. A seismicity increase in northern California during the first 24 hours following an earthquake in southern California and a decrease during the next 48 hours were also noted. A seismicity increase was observed in the Long Valley caldera during the first 24 hours following an M ≥ 5 earthquake in southern California and a decrease during the next 48 hours. We also discuss some causes of this trigger effect, in view of the fact that the external excitations had low intensity. No seismicity changes have been detected in southern and northern California during powerful typhoons in the northeastern Pacific and during magnetic storms.     

Heat flow,radioactive heat generation,and theoretical tectonics for northwestern Mexico

Nine heat flow values from Baja California and Sonora represent the first determinations of heat flux from Mexico and, in general, justify southerly extensions of the Basin and Range and Southern California thermal provinces of the southwestern United States. Heat flow in northern Baja California is low (0.84 hfu), consistent with known values from the Sierra Nevada Batholith, but a value of 1.23 hfu was recorded in the central area of the peninsula. Seven measurements from Sonora, averaging 2.5 hfu, are similar to Basin and Range values.Reduced heat flow values (q*) have been calculated for Sonora and are interpreted as indicative of a separate Basin and Range thermal subprovince in Mexico. A tectonic model developed for northwestern Mexico attributes the high heat flow of the Basin and Range to behind arc extension associated with the termination of Cenozoic subduction. Opening of the Gulf of California and sea-floor spreading therein has provided a vent for the release of heat accumulated under northwestern Mexico. Thus, the southern portion of the Basin and Range province (in Mexico) appears to be cooling and narrowing and a subprovince of high reduced heat flow is defined east and perhaps southwest of the Gulf of California.     

简介加利福尼亚理工学院建筑结构健康状态的实时监测和性能评估系统

介绍了加利福尼亚理工学院建筑结构健康状态的实时监测和性能评估系统近年来的发展。该系统安装在帕斯迪纳市的加利福尼亚理工学院校园里的米利肯图书馆内。它通过互联网向全世界提供真实的实时数据。     

Old cannery wastes,a potential source of trace metals in the marine environment

High levels of lead and zinc have been measured in the California Mussel Mytilus californianus taken from southern Monterey Bay as part of the California State Mussel Watch programme. The levels of lead and zinc increase steadily from Cypress Point towards Cannery Row. The California State Water Resources Control Board (which funded but did not conduct the State Mussel Watch) has attributed the high levels to heavy metals contributed by sewage. The state mussel watch data reports have not considered the historic canning wastes from more than 30 canneries along Cannery Row as a possible source of trace metals. Leachates from old cannery wastes may be a major source of lead and zinc in mussels in southern Monterey Bay and must be considered in assessing any data from the State Mussel Watch programme.     

A Forward Test of the Precursory Decelerating and Accelerating Seismicity Model for California

Accelerating strain energy released by the generation of intermediate magnitude preshocks in a broad (critical) region, and decelerating energy released in a narrower (seismogenic) region, is considered as a distinct premonitory pattern useful in research for intermediate-term earthquake prediction. Accelerating seismicity in the broad region is satisfactorily interpreted by the critical earthquake model and decelerating seismicity in the narrower region is attributed to stress relaxation due to pre-seismic sliding. To facilitate the identification of such patterns an algorithm has been developed on the basis of data concerning accelerating and decelerating preshock sequences of globally distributed already occurred strong mainshocks. This algorithm is applied in the present work to identify regions, which are currently in a state of accelerating seismic deformation and are associated with corresponding narrower regions, which are in a state of decelerating seismic deformation in California. It has been observed that a region which includes known faults in central California is in a state of decelerating seismic strain release, while the surrounding region (south and north California, etc.) is in a state of accelerating seismic strain release. This pattern corresponds to a big probably oncoming mainshock in central California. The epicenter, magnitude and origin time, as well as the corresponding model uncertainties of this probably ensuing big mainshock have been estimated, allowing a forward testing of the model's efficiency for intermediate-term earthquake prediction.     

Development of the ElarmS methodology for earthquake early warning: Realtime application in California and offline testing in Japan

In July 2009, the California Integrated Seismic Network concluded a three-year study of earthquake early warning systems in California. Three algorithms were expanded and examined during the study. Here we discuss the history, methodology, and performance of one of the algorithms, ElarmS. Earthquake Alarm Systems, or ElarmS, uses peak displacement and maximum predominant frequency of the P-wave to detect earthquakes and quantify their hazard in the seconds after rupture begins. ElarmS was developed for Northern and Southern California, and now processes waveforms in realtime from 603 seismic sensors across the state. We outline the methodology as currently implemented, present several example events from different regions of California, and summarize the performance in terms of false and missed alarms. ElarmS was also tested offline with a dataset of 84 large magnitude earthquakes from Japan. The results from the Japan dataset were used to create a statistical error model for the algorithm. The model can be used to provide realtime uncertainty estimates at any stage in processing. In August 2009 the CISN embarked on a second three-year study of earthquake early warning. As part of this ongoing research, we identify the technological and methodological challenges facing ElarmS. Telemetry latencies and false alarm rates are two key opportunities for improvement.     

Comparison between the Chile and Mexico triple junction areas substantiates slab window development beneath northwestern Mexico during the past 12-10 Myr

When combined with the Miocene-Recent volcanic record of Baja California, a parallel drawn between the Chile and Mexico triple junction areas substantiates slab window development beneath northwestern Mexico during the past 12-10 Myr. The slab-free zone manifestations challenge the notion that ridge subduction has not occurred beneath the southern Baja California peninsula. The geochemically distinctive rocks from the Santa Clara volcanic field of west-central Baja California, including coeval adakites and niobium-enriched basalt, are commonly inferred to signal partial melting of the subducting plate at shallow depths and relatively high temperatures, before slab dehydration occurs. Such PT conditions for slab melting have only been observed in association with spreading-ridge subduction. We propose that slab window development beneath southern Baja California and mainland Mexico (30° to 18°N) resulted from subduction of the East Pacific rise.     

Validation of predicted meteorological drought in California using analogous orbital geometries

Recent studies have uncovered the predictability of hydrological conditions on Earth, based on an analysis of long‐term precipitation data in California and analogous orbital forcings during different years that are separated by Saros cycles. With similar orbital geometries of the Earth and Moon, water years 1976 and 1994, which are one and two Saros cycles apart from water year 2012, respectively, were both Critically Dry years in California, according to the California Department of Water Resources’ water year type classification. Further analysis of precipitation data at a cross section of gauging stations across the U.S. during water years 1976 and 1994 reinforces the previously observed association between analogous orbital forcings and hydrological conditions on earth. The current work is a validation of predicted meteorological drought in California during water year 2012 using: (1) real‐time precipitation data collected from a cross section of gauging stations across California, and (2) estimated full natural flows of eight major rivers in California. The data for these years were analyzed and found to have a high level of correlation. The results of the current work provide a significant mark in the validation exercises of the recent novel finding of the predictability of earth's meteorological and hydrological variability. Continued studies and mapping of observed hydrological conditions globally in the coming years using this approach will be highly valuable for sustainable water resources engineering and various other applications. Copyright © 2013 John Wiley & Sons, Ltd.     

Investigation on the Load/Unload Response Ratio With Coda Q-1 as Response

The load/unload response ratio YQ with the geophysical parameter coda Q-1 of the crust as response is denned in this study.The variation in YQ-1 before and after the Northridge earthquake of January 17,1994(California)has been investigated by using the data of coda Q-1 with frequencies of 1.5,3.0,6.0,12.0,and 24.0 Hz in the Southern California from 1987 to 1994.It can be found that YQ-1 for coda waves with all frequencies,the frequency of 12.0 Hz excluded,ascended to a certain extent prior to the occurrence of the rnainshock and returned to normality after the main shock.     

Assessing marine debris in deep seafloor habitats off California

Marine debris is a global concern that pollutes the world’s oceans, including deep benthic habitats where little is known about the extent of the problem. We provide the first quantitative assessment of debris on the seafloor (20-365 m depth) in submarine canyons and the continental shelf off California, using the Delta submersible. Fishing activities were the most common contributors of debris. Highest densities occurred close to ports off central California and increased significantly over the 15-year study period. Recreational monofilament fishing line dominated this debris. Debris was less dense and more diverse off southern than central California. Plastic was the most abundant material and will likely persist for centuries. Disturbance to habitat and organisms was low, and debris was used as habitat by some fishes and macroinvertebrates. Future trends in human activities on land and at sea will determine the type and magnitude of debris that accumulates in deep water.     

Introduction to ‘A tribute to Edward P. Glenn (1947–2017): A legacy of scientific environmental assessment and applications in hydrological processes’

This special issue (SI) ‘A Tribute to Edward P. Glenn (1947-2017): A legacy of Scientific Environmental Assessment and Applications in Hydrological Processes’ is a celebration of the extensive work of Dr. Ed Glenn that was instrumental across multiple sub-disciplines of hydrology. The SI highlights four primary areas of hydrological processes that are cornerstones of Ed Glenn's over four decades of research. These contributions cover the following specialties: (i) Hydrology in the Colorado River Delta; (ii) Riparian ecosystem water use; (iii) Riparian Plant ecophysiology and ecohydrology; and (iv) Methods and models to characterize evapotranspiration. Since Ed was passionate about the dryland delta at the end of the Colorado River, we begin with four research studies that focus on this special region on the U.S.–Mexico border which encompasses four states (Baja and Sonora in Mexico and California and Arizona in United States) as well as tribal communities in the transboundary area. The Colorado River delta reaches the Northern Gulf of California in the Sea of Cortez which has been designated as a UNESCO international biosphere reserve (‘Reserva de la Biosfera El Pinacate y Gran Desierto de Altar’), which includes the Upper Gulf of California and Delta of the Colorado River (‘Reserva de la Biosfera Alto Golfo de California y Delta del Río Colorado’). Ed spent the majority of his last three decades on water balance studies and on ground-based transpiration quantification for validation of satellite and airborne remote sensing methods. We wrap up the special issue with contributions related to improving satellite and airborne remote sensing estimation of actual evapotranspiration. It is our pleasure to summarize the 16 research studies contributed to the special issue to honour Ed Glenn's research interests.     

1979年加州凯奥蒂湖地震序列震源机制分析:美国加州地震比中国大陆地震破裂过程简单的证据

本文详细分析了1979年美国加利福尼亚凯奥蒂湖地震序列在时间和空间之中发展的非常有序的过程.对凯奥蒂湖地震序列,在三种情况下分别做出34次地震的断层面解.分析了美国地质调查局观测报告中地震初动的可信性.论证了伯克利加利福尼亚大学的地壳模型与美国地质调查局的地壳模型对于求断层面解的等效性.与唐山地震序列相比,凯奥蒂湖地震序列表现出4个主要特点:1.震中分布呈规则的狭长条带,与断层的关系密切;2.断层面解中出现的矛盾初动少;3.断层面解之间的一致性好;4.断层面解随时间没有明显的变化.这些都表明,凯奥蒂湖地震序列比唐山地震序列特征简单,前者基本上是沿卡拉维拉斯断层发生的面破裂,而后者却是在一定震源区中发生的体破裂.唐山地震序列的特征在中国大陆是有代表性的.若凯奥蒂湖地震序列的这些特点,在加州也具有代表性,则这两个地震序列的差别,可以作为美国加州地震比中国大陆地震发生环境和发生过程都简单的一个证据.     

1979年加州凯奥蒂湖地震序列震源机制分析:美国加州地震比中国大陆地震破裂过程简单的证据

本文详细分析了1979年美国加利福尼亚凯奥蒂湖地震序列在时间和空间之中发展的非常有序的过程.对凯奥蒂湖地震序列,在三种情况下分别做出34次地震的断层面解.分析了美国地质调查局观测报告中地震初动的可信性.论证了伯克利加利福尼亚大学的地壳模型与美国地质调查局的地壳模型对于求断层面解的等效性.与唐山地震序列相比,凯奥蒂湖地震序列表现出4个主要特点:1.震中分布呈规则的狭长条带,与断层的关系密切;2.断层面解中出现的矛盾初动少;3.断层面解之间的一致性好;4.断层面解随时间没有明显的变化.这些都表明,凯奥蒂湖地震序列比唐山地震序列特征简单,前者基本上是沿卡拉维拉斯断层发生的面破裂,而后者却是在一定震源区中发生的体破裂.唐山地震序列的特征在中国大陆是有代表性的.若凯奥蒂湖地震序列的这些特点,在加州也具有代表性,则这两个地震序列的差别,可以作为美国加州地震比中国大陆地震发生环境和发生过程都简单的一个证据.     

Elements in fish of Malibu Creek and Malibu Lagoon near Los Angeles,California

Our aim was to assess whether past discharges from a wastewater treatment plant increased metal pollutant loads in stream mobile species in a one-day baseline sampling study that included a coastal wetland. Mosquitofish (Gambusia affinis) of two sizes, black bullhead (Ameiurus melas), and crayfish (Pacifastacus leniusculus) were collected from Malibu Creek, and California killifish (Fundulus parvipinnis) of three sizes, as well as arroyo chub (Gila orcutti) were sampled from Malibu Lagoon near Los Angeles, California. Species from each locality were pooled by length, homogenized, digested by microwave wet ashing, and analyzed by simultaneous inductively coupled plasma atomic emission spectroscopy for 27 elements. Lagoon killifish 2.0-3.5 cm long contained levels of arsenic and lead above the levels for 95% of California fish, the EDL95. Black bullhead upstream of the discharge contained elevated levels of As, Cr and Se. Young mosquitofish <3 cm in length upstream of the discharge differed greatly in the order of abundance of their elements relative to larger mosquitofish and to other species collected. More sampling than this baseline study allowed was needed to determine if the wastewater treatment plant was a pollution source.     

History of Modern Earthquake Hazard Mapping and Assessment in California Using a Deterministic or Scenario Approach

Modern earthquake ground motion hazard mapping in California began following the 1971 San Fernando earthquake in the Los Angeles metropolitan area of southern California. Earthquake hazard assessment followed a traditional approach, later called Deterministic Seismic Hazard Analysis (DSHA) in order to distinguish it from the newer Probabilistic Seismic Hazard Analysis (PSHA). In DSHA, seismic hazard in the event of the Maximum Credible Earthquake (MCE) magnitude from each of the known seismogenic faults within and near the state are assessed. The likely occurrence of the MCE has been assumed qualitatively by using late Quaternary and younger faults that are presumed to be seismogenic, but not when or within what time intervals MCE may occur. MCE is the largest or upper-bound potential earthquake in moment magnitude, and it supersedes and automatically considers all other possible earthquakes on that fault. That moment magnitude is used for estimating ground motions by applying it to empirical attenuation relationships, and for calculating ground motions as in neo-DSHA (Zuccolo et al., 2008). The first deterministic California earthquake hazard map was published in 1974 by the California Division of Mines and Geology (CDMG) which has been called the California Geological Survey (CGS) since 2002, using the best available fault information and ground motion attenuation relationships at that time. The California Department of Transportation (Caltrans) later assumed responsibility for printing the refined and updated peak acceleration contour maps which were heavily utilized by geologists, seismologists, and engineers for many years. Some engineers involved in the siting process of large important projects, for example, dams and nuclear power plants, continued to challenge the map(s). The second edition map was completed in 1985 incorporating more faults, improving MCE??s estimation method, and using new ground motion attenuation relationships from the latest published results at that time. CDMG eventually published the second edition map in 1992 following the Governor??s Board of Inquiry on the 1989 Loma Prieta earthquake and at the demand of Caltrans. The third edition map was published by Caltrans in 1996 utilizing GIS technology to manage data that includes a simplified three-dimension geometry of faults and to facilitate efficient corrections and revisions of data and the map. The spatial relationship of fault hazards with highways, bridges or any other attribute can be efficiently managed and analyzed now in GIS at Caltrans. There has been great confidence in using DSHA in bridge engineering and other applications in California, and it can be confidently applied in any other earthquake-prone region. Earthquake hazards defined by DSHA are: (1) transparent and stable with robust MCE moment magnitudes; (2) flexible in their application to design considerations; (3) can easily incorporate advances in ground motion simulations; and (4) economical. DSHA and neo-DSHA have the same approach and applicability. The accuracy of DSHA has proven to be quite reasonable for practical applications within engineering design and always done with professional judgment. In the final analysis, DSHA is a reality-check for public safety and PSHA results. Although PSHA has been acclaimed as a better approach for seismic hazard assessment, it is DSHA, not PSHA, that has actually been used in seismic hazard assessment for building and bridge engineering, particularly in California.     

Temporal variability of the physical and chemical water characteristics at a coastal monitoring observatory: Station ENSENADA

The temporal variability of the physical and chemical conditions of coastal waters off Ensenada, Baja California (Mexico) was characterized. A historical analysis was made based on 11 years (1998–2008) of temperature and salinity data records measured quarterly by IMECOCAL, along a transect perpendicular to the coast (CalCOFI line 100). Moreover, the physical and chemical conditions at a coastal monitoring observatory called station ENSENADA were described using a 2-year data series (October 2006–November 2008) obtained with improved temporal resolution. The historical analysis of line 100 showed marked seasonal variability in the thermohaline conditions associated with fluctuations in the flow of the equatorward California Current and the poleward California Undercurrent, as well as with coastal upwelling events whose magnitude and frequency increase towards spring–summer. Interannual variability was also observed, related to warm and/or cold ENSO phases that modify the characteristics of the water column in this coastal region. The most striking characteristics of the interannual variability at station ENSENADA were La Niña conditions recorded from summer 2007 to mid 2008. During this cold ENSO phase, temperature, salinity, dissolved oxygen, density, and dissolved inorganic carbon data revealed the anomalous presence of subsurface water at the surface layers in spring 2008. Results suggest that the coastal observatory is sensitive to the temporal variability of hydrographic conditions on shelf coastal waters (<50 km) off Ensenada in the northern BC region. Consequently, station ENSENADA would be a good location to high-frequency monitors the oceanographic conditions of the transitional region between tropical/subtropical and subarctic systems of the California Current System.     

华北与加利福尼亚中部沿海地区地震活动性C值的对比(英文)

为了解加州中部沿海的地震活动特征,本文利用了C值方法分析了过去36年的加州中部沿海地区地震资料,并与b值和地震频度结果进行了对比。分析了36年地震活动的基本情况。华北和加州中部沿海地区的C值资料分析表明,地震的空间分布不是随机的也不服从泊松分布。C值、b值和地震频度这三个定量的参数能够描述过去36年里加州中部沿海地区的地震活动的基本特征。     

Migration of historical earthquakes in California

Most large earthquakes of magnitude 6.0 in California during 1852–1987 appear to show a southeast-to-northwest tendency of epicenter migration. This finding is consistent with earlier findings ofSavage (1971) for a relatively few large earthquakes along the west coast of North America, and ofWood andAllen (1973) for smaller events along the San Andreas fault in central California. The average speed of migration is approximately 130 km/yr, which is within the range of speeds observed for other major seismic zones in the world. The epicenter migration in California may be the result of some small but broad-scaled episodic strain changes associated with creep waves induced by magma injections at the East Pacific Rise and propagating northwestwardly along a broad transform boundary between the Pacific and North American plates at subseismogenic depths as proposed bySavage (1971).