Decadal Forecasts of Large Earthquakes along the Northern San Andreas Fault System, California: Increased Activity on Regional Creeping Faults Prior to Major and Great Events

The three largest earthquakes in northern California since 1849 were preceded by increased decadal activity for moderate-size shocks along surrounding nearby faults. Increased seismicity, double-difference precise locations of earthquakes since 1968, geodetic data and fault offsets for the 1906 great shock are used to re-examine the timing and locations of possible future large earthquakes. The physical mechanisms of regional faults like the Calaveras, Hayward and Sargent, which exhibit creep, differ from those of the northern San Andreas, which is currently locked and is not creeping. Much decadal forerunning activity occurred on creeping faults. Moderate-size earthquakes along those faults became more frequent as stresses in the region increased in the latter part of the cycle of stress restoration for major and great earthquakes along the San Andreas. They may be useful for decadal forecasts. Yearly to decadal forecasts, however, are based on only a few major to great events. Activity along closer faults like that in the two years prior to the 1989 Loma Prieta shock needs to be examined for possible yearly forerunning changes to large plate boundary earthquakes. Geodetic observations are needed to focus on identifying creeping faults close to the San Andreas. The distribution of moderate-size earthquakes increased significantly since 1990 along the Hayward fault but not adjacent to the San Andreas fault to the south of San Francisco compared to what took place in the decades prior to the three major historic earthquakes in the region. It is now clear from a re-examination of the 1989 mainshock that the increased level of moderate-size shocks in the one to two preceding decades occurred on nearby East Bay faults. Double-difference locations of small earthquakes provide structural information about faults in the region, especially their depths. The northern San Andreas fault is divided into several strongly coupled segments based on differences in seismicity.

Unsheltered: Navigating California’s Homelessness Crisis

This paper presents a comprehensive exploration of the complex phenomenon of homelessness in California,with a specific focus on the state’s three largest cities-Los Angeles,San Francisco,and San Diego.Against the backdrop of a high cost of living and a housing market strained by insufficient affordable options,the multifaceted nature of social diversity further complicates the landscape,leading to a widespread presence of homelessness that spans both major urban centers and rural regions.Through an in-depth examination of the distinct challenges confronting each city,ranging from housing shortages to intricate social dynamics,this study seeks to illuminate the underlying factors driving homelessness and identify potential avenues for intervention.Moreover,the paper delves into the unique vulnerabilities experienced by certain demographics within the homeless population,including veterans,families with children,and LGBTQ+individuals,highlighting the critical need for targeted solutions tailored to their specific needs.By synthesizing existing research and incorporating firsthand accounts,this research endeavor aims to contribute to a deeper understanding of homelessness in California and inform the development of comprehensive strategies aimed at fostering inclusive,sustainable communities statewide.

First Successful Nesting of Black Oystercatchers among Endangered California Least Terns along the West Coast of North America

A pair of Black Oystercatchers(Haematopus bachmani)established a nest in June 2022 at“Tern Town”,an island located in Hayward,California along the eastern side of the San Francisco Bay.This is the first documented occurrence of oystercatchers successfully nesting and fledgling young in association with California Least Terns.The island provides nesting habitat for three special status species.Since 2015,and for a total of six breeding seasons,the endangered California Least Tern(Sternula antillarum browni),the threatened Western Snowy Plover(Charadrius alexandrinus nivosus)and species-of-special-concern Black Skimmer(Rynchops niger),have nested successfully,in association with American Avocet(Recurvirostra americana)and Black-necked Stilt(Himantopus mexicanus).We collected shells near the oystercatcher nest to assess their diet.Diet data showed the oystercatchers foraged on,in decreasing order of abundance,Japanese Little-necked Clams(Ruditapes philippinarum),Ribbed Mussels(Geukensia demissa),Bent-nose Clams(Macoma nasuta),Limpets(Patellogastropoda sp.)and Bay Mussels(Mytilus edulis).This new report on breeding Black Oystercatchers indicates that managing habitat for California Least Tern,Western Snowy Plover,and Black Skimmer can also benefit Black Oystercatcher.This site-specific information on breeding Black Oystercatchers supports recovery plan tasks that are consistent with managing habitat for California Least Tern,Western Snowy Plover and Black Skimmer.

A/California/7/2009与A/California/4/2009病毒感染力比较

目的甲型H1N1流感病毒A/California/7/2009与A/California/4/2009病毒序列比较同源性在99%以上,本实验旨在比较两株病毒感染BALB/c小鼠研究感染力强弱。方法分别将A/California/7/2009（CA7）与A/California/4/2009（CA4）两株病毒分别连续10倍稀释后,对4~6周龄雌性BALB/c小鼠经乙醚麻醉后进行滴鼻攻毒,每个稀释度接种10只实验小鼠,测定CA7 MLD50为101.24/0.05 mL,检测小鼠感染、致病的多项指标,观察期为14 d。结果相同TCID50的CA7和CA4病毒感染小鼠,CA4感染小鼠后14 d内死亡率为20%,而CA7感染小鼠后8 d内死亡率为100%。CA7 106TCID50感染的小鼠病理表现为重度弥漫性间质性肺炎,CA4 106TCID50感染的小鼠病理表现为中度-重度间质性肺炎。结论在相同条件下,CA7感染力明显强于CA4。

California Bearing Ratio for Cohesive Soils from Quasi Static Cone Tests

The California bearing ratio (CBR) test is the most widely spread method of determining the bearing strength of the pavement material and is fundamental to pavement design practice in most countries. This test is expensive, laborious and time consuming, and to overcome this, Quasi static cone penetrometer machine was fabricated and used to measure the consistency limits (liquid limit-LL, Plastic limit-PL and Plasticity index-PI), which were used to develop an empirical equation to determine CBR. Soil samples were collected and unsoaked CBR, PL, LL and PI were determined according to BS 1377 part 9 and BS 1377-2;1990. Quasi static penetration forces at 20 mm depth of penetration were also determined at consistency limits. It was found that the force of 1020 gf and 60 gf was achieved at a depth of 20 mm at PI and LL respectively. The correlation and regression analysis between consistency limits, and the experimental CBR obtained showed coefficient of determination, R2 = 0.907 between CBR and all the parameters using multiple linear regression analysis (MLRA). The regression equation developed was used together with the relationship developed between the Quasi static Penetration force at consistency limits and the tested consistency limits to come up with the General Empirical Equation. Verification of the formula showed that the correlation can be used accurately to determine the un soaked CBR.

Baja California边缘PC14岩芯海水表层温度及生产力变化的百年尺度记录

加利福尼亚流是北太平洋环流的重要组成部分,它的变化对全球气候及碳循环有重要影响。对位于东北太平洋低纬区Baja California外海的PC14柱状样进行了有机地球化学分析,重建了过去14ka来这一地区百年尺度的海水表面温度及生产力变化,发现其存在明显的B/A(Bling-Aller)和YD(Younger Drays)事件,但B/A和YD事件温度变化幅度小于中纬度地区。与中纬度加利福尼亚流系早中全新世温度降低不同,PC14全新世温度无明显变化趋势。这些结果表明了东太平洋低纬地区对高纬地区的气候响应以及沿岸上升流和ENSO现象对加利福尼亚流系中纬和低纬地区的影响不同。从冰消期到全新世,PC14生产力呈现阶段上升趋势,指示了由E1 Ni?o气候向La Ni?a气候的转化以及沿岸上升流加强的总体趋势。在全新世中后期(6.5—3.8ka)生产力的降低,则可能是受ENSO加强的影响。在B/A暖期,PC14生产力增加不多,但氧最小层强度增加,这表明生产力变化不是东太平洋边缘海的氧最小层强化的控制因素。

A/California/07／2009亚型猪流感冷适应减毒疫苗株的拯救及免疫效果评价

应用反向遗传学技术,选择冷适应、温度敏感、减毒的A/Ann Arbor/6/60 ca(H2N2)型流感病毒的6个内部基因为骨架,与A/California/07/2009株流感病毒2个抗原基因HA、NA分别克隆到polⅠ-polⅡ转录表达载体pAD3000中,构建8个转录表达载体重组质粒,共转染Vero细胞,获得重配A/California/07/2009ca株流感病毒.重配病毒的TCID50为7.5,病毒传4代后其血凝素(HA)滴度稳定在1∶256,半数感染剂量EID50为8,鸡胚传20代,经RT-PCR鉴定未发现重组病毒基因突变,电镜观察重配病毒符合流感病毒的主要特征;蔗糖纯化的病毒经肌肉注射(灭活)及滴鼻(减毒活病毒)两种途径免疫BALB/c小鼠,结果显示:滴鼻免疫和肌肉注射都可以产生较高效价的血凝抑制(HI)抗体,肌肉注射组产生的HI抗体略高(P=0.044),但肌肉注射组检测不到高效价IgA抗体;滴鼻免疫组鼻冲洗液中可以检测到高效价的IgA抗体,同型病毒感染后,IL-1β、TNFα、IFN-α等前炎因子分泌较早,且高于肌肉注射组(P<0.05),可见,喷鼻减毒疫苗比灭活全病毒疫苗能更好地激发黏膜免疫反应.通过对小鼠各个器官病毒载量的检测发现,4天后鼻腔、气管、脑、肺、脾脏没有病毒存在,证明减毒活疫苗株在小鼠上是安全的.以上数据可以初步断定,重组病毒有作疫苗候选株的可能,而且喷鼻疫苗具有降低免疫剂量、同时激活体内体液免疫和细胞免疫的功能.

减毒流感病毒A/California/07/2009ca疫苗候选株在雪貂上的保护性研究

目的:评价减毒A/California/07/2009ca流感病毒在雪貂上的减毒性及免疫保护性。方法:减毒A/California/07/2009ca流感病毒和BJ501病毒滴鼻免疫雪貂。应用TCID50的方法检测雪貂不同时间点的各个器官的病毒载量。结果:减毒A/California/07/2009ca流感病毒初次免疫后雪貂的精神状态、死亡率、体重没有变化,一免4天后雪貂鼻腔内无病毒复制,A/California/07/2009ca流感病毒二免14天免疫BJ501病毒,BJ501病毒在鼻腔、肺中的毒力(TCID50)显著降低。结论:实验证明减毒A/California/07/2009ca病毒在雪貂上无致病性,是减毒的流感病毒株。通过雪貂免疫保护性实验证明,减毒A/California/07/2009ca病毒具有一定的免疫保护效果,这些实验结论的获得为今后流感减毒喷鼻疫苗的研制提供了有力的数据支持。

A new electroplated Ir/Ir(OH)_x pH electrode and its application in the coastal areas of Newport Harbor, California

Resulting from the rising levels of atmospheric carbon, ocean acidification has become a global problem. It has significant impacts on the development, survival, growth and physiology of marine organisms. Therefore, a high- precision sensor is urgently needed to measure the pH of sea-water. Iridium wire with a diameter of 0.25 mm is used as the substrate, and an Ir/Ir（OH）x pH electrode is prepared by a one-step electrochemical method in a LiOH solution at the room temperature. A scanning electron microscope （SEM） observation reveals that it is coated with nanoscale particles. In laboratory tests, the electrode exhibits a very promising pH response, with an ideal Nernst slope （56.14-59.52）, fast response, good stability and long fife-span in tested pH buffer solutions. For a sea trial, four pH electrodes and one Ag/AgC1 reference electrode are integrated with a self-made chemical sensor, and a profile detection of nearly 70 m is implemented near Newport Harbor, California on August 3, 2015. The results reflect that the pH value measured by the sensor is very close to the data given by Sea-Bird 911 plus CTD, with a difference value ranging from 0.000 075 to 0.064 719. And the sensor shows a better data matching degree in 0-40 m water depth. In addition, the high precision and accuracy of the sensor make it possible to use in the ocean observation field.

Effect of natural and synthetic fibers reinforcement on California bearing ratio and tensile strength of clay

Use of environmentally friendly approaches with the purpose of strengthening soil layers along with finding correlations between the mechanical characteristics of fiber-reinforced soils such as indirect tensile strength(ITS)and California bearing ratio(CBR)and as well as the evaluation of shear strength parameters obtained from the triaxial test would be very effective at geotechnical construction sites.This research was aimed at investigating the influence of natural fibers as sustainable ones including basalt(BS)and bagasse(BG)as well as synthetic polyester(PET)fibers on the strength behavior of clayey soil.To this end,the effects of various fiber contents(0.5%,1%and 2%)and lengths(2.5 mm,5 mm and 7.5 mm)were experimentally evaluated.By conducting ITS and CBR tests,it was found that increasing fiber content and length had a significant influence on CBR and ITS values.Moreover,2%of 7.5 mm-long fibers led to the largest values of CBR and ITS.The CBR values of soil reinforced with PET,BS,and BG fibers were determined as 19.17%,15.43%and 13.16%,respectively.The ITS values of specimens reinforced with PET,BS,and BG fibers were reported as 48.57 kPa,60.7 kPa and 47.48 kPa,respectively.The results of the triaxial compression test revealed that with the addition of BS fibers,the internal friction angle increased by about 100%,and with the addition of PET fibers,the cohesion increased by about 70%.Moreover,scanning electron microscope(SEM)analysis was employed to confirm the findings.The relationship between CBR and ITS values,obtained via statistical analysis and used for the optimum design of road pavement layers,demonstrated that these parameters had high correlation coefficients.The outcomes of multiple linear regression and sensitivity analysis also confirmed that the fiber content had a greater effect on CBR and ITS values than fiber length.

Monitoring of Net Primary Production in California Rangelands Using Landsat and MODIS Satellite Remote Sensing

In this study, we present results from the CASA (Carnegie-Ames-Stanford Approach) model to estimate net primary production (NPP) in grasslands under different management (ranching versus unmanaged) on the Central Coast of California. The latest model version called CASA Express has been designed to estimate monthly patterns in carbon fixation and plant biomass production using moderate spatial resolution (30 m to 250 m) satellite image data of surface vegetation characteristics. Landsat imagery with 30 m resolution was adjusted by contemporaneous Moderate Resolution Imaging Spectroradiometer (MODIS) data to calibrate the model based on previous CASA research. Results showed annual NPP predictions of between 300 - 450 grams C per square meter for coastal rangeland sites. Irrigation increased the predicted NPP carbon flux of grazed lands by 59 grams C per square meter annually compared to unmanaged grasslands. Low intensity grazing activity appeared to promote higher grass regrowth until June, compared to the ungrazed grassland sites. These modeling methods were shown to be successful in capturing the differing seasonal growing cycles of rangeland forage production across the area of individual ranch properties.

Ambient tectonic shear stress field in Southern California and seismic hazard regions

ccording to the fracture mechanics rupture model of earthquakes put forward by us, several equations to compute tectonic ambient shear stress value τ0 have been derived [equations (1), (2), (3), (5)].τ0 values for intermediate and small earthquakes occurred in Chinese mainland and Southern California have been calculated by use of these equations. The results demonstrate that the level and distribution of τ0 are closely related to the location where large earthquakes will occur, i.e. the region with higher level of τ0 will be prone to occur large earthquakes and the region with lower level will usually occur small earthquakes. According to the spatial distribution of τ0 , the seismic hazard regions or the potential earthquake source regions can in some degree be determined. According to the variation of τ0 with time, the large earthquake occurrence time can be roughly estimated. According to the distribution of τ0 in Southern California and variation with time, three high stress level regions are determined, one (Goldfield area) of them is the present seismic hazard region.

P-wave tomography of crust and upper mantle under Southern California: Influence of topography of Moho discontinuity

We use 146 422 P-wave arrival times from 6 347 local earthquakes recorded by the Southern California SeismicNetwork to determine a detailed three-dimensional P-wave velocity structure at 0～35 km depth. We have takeninto account the Moho depth variations, which were obtained by seismological methods. Checkerboard tests sug-gest that our inversion results are reliable. Our models provide new information on regional geological structuresof Southern California. At shallow depths P-wave velocity structure correlates with surface geological features andexpresses well variations of surface topography of the mountains and basins. The velocity structure at each layer ischaracterized by block structures bounded by large faults. Ventura Basin, Los Angeles Basin, Mojave Desert, Pen-insular Ranges, San Joaquin Valley, Sierra Nevada, and Salton Trough show respectively all-round block. SanAndreas Fault becomes an obvious boundary of the region. To its southwest, the velocity is higher, and there arestrong heterogeneity and deeper seismicity; but to its northeast, the velocity is lower and shows less variation thanto the southwest, the seismicity is shallower. To investigate the effect of the Moho geometry we conducted inver-sions for two cases: one for flat Moho geometry, another for a Moho with lateral depth variations. We found thatthe topography of the Moho greatly affects the velocity structure of the middle and lower crust. When the Mohotopography is considered, a more reasonable tomographic result can be obtained and the resulting 3-D velocitymodel fits the data better.

Measurements of Fog Water Deposition on the California Central Coast

Fog deposition is a notable component of the water budget of herbaceous-shrub ecosystems on the central and southern coastal regions of California. This paper presents an analysis of fog water deposition rates and meteorological controls in Big Sur, California. Mesh-screen fog collectors were installed the Brazil Ranch weather station sites to measure fog water during the summer seasons of 2010 and 2011. Fog deposition occurred during 73% of days recorded in 2010 and 87% of days recorded in 2011. The daily average deposition rate was 2.29 L/m2 in 2010 and 3.86 L/m2 in 2011. The meteorological variables which had the greatest influence on prediction of fog deposition were wind speed, wind direction, and the dew-point depression (difference between air temperature and dew point). Based on these results, we hypothesize that high rates of summer fog deposition help sustain the productivity of California coastal vegetation through periods of low rainfall.

Vegetation Regrowth Following Wildfires in the Santa Cruz Mountains of Northern California Monitored Using Landsat Satellite Image Analysis

The Santa Cruz Mountain range in northern California is a coastal landscape with a history of extensive forest logging and frequent large wildfires that have recently destroyed numerous residential structures at the wildland interface. Results from Landsat satellite image time-series analysis since 1984 of the study area within the Los Gatos Creek and Corralitos Creek watersheds showed that none of the severe drought periods since the 1980s have notably inhibited rapid tree and shrub regrowth rates on steep hill slopes burned recently by the 1985 Lexington Fire and the 2008 Summit Fire. In high burn severity areas of both fires, post-fire vegetation types showed a marked increase in shrub cover, mainly at the expense of evergreen tree cover. Most of these low (<3 m), dense stands of evergreen woody species have regenerated in as little as five years from bare charred ground. A combination of Landsat and Laser Altimeter (GLAS) satellite sensor data revealed that exposed south-facing slopes are presently supporting 200 to 240 Mg·ha-1 of standing woody biomass on the burned areas. This study is the first of its kind to utilize a full 30-year record of Landsat vegetation index data to monitor tree and shrub regrowth after stand-replacing wildfires in California.

Intermediate-Term Seismic Precursors to the Loma Prieta California Earthquake of 1989

We use precise locations of earthquakes to study forerunning seismic activity to the 1989 Loma Prieta earthquake of magnitude 6.9 to the south of San Francisco, California, USA. Relocated shocks of magnitude 4.3 to 5.4 and smaller micro-earthquakes define a distinct zone of nearly the same orientation as the mainshock. That separate zone broke in the 15 months prior to the 1989 mainshock. That feature, which we call the Lake Elsman fault zone, is identified as the site of a prominent intermediate-term (yearly) precursor very close to the coming 1989 mainshock. That zone experienced a relatively large stress decrease during the nearby great earthquake of 1906. From the occurrence of the Lake Elsman shocks, we deduce that stress drop was only restored in the 15 months prior to the 1989 main event. Those stresses are consistent with little forerunning seismic activity in the region after 1906, later increases just before the 1989 mainshock and a decrease in activity thereafter. The southern Santa Cruz mountains segment of the San Andreas Fault zone, the location of the 1989 mainshock, had not been the site of events of magnitude 5 and larger for many decades prior to the occurrence of Lake Elsman earthquakes of magnitude 5.3 and 5.4 in 1988 and 1989. High-preci- sion locations readily available in real-time might be used to monitor similar possible precursory activity very close to the San Andreas and other transform faults.

Full time adult credential students?instructional preferences at California State University, Long Beach: pedagogy or andragogy?

This study investigated the instructional preferences of full time adult credential students after they took a live course called Principles of Adult Education at California State University, Long Beach (CSULB) in the fall semester of 2002. These full time adult credential students had been working on their adult teaching credentials to meet the competencies specified by the California Commission on Teacher Credentialing. The course introduced students to Andragogy developed by Malcolm Knowles out of the andragogical model developed by Lindeman (1926). The study used Principles of Adult Learning Scales (PALS), advanced by Gary Conti in 1983 to measure instructional preferences. Data were collected from 30 (100% of 30) full time adult credential students enrolled in a live course to determine their instructional preferences of helping adults learn. The results of the study showed in most cases these adult learning professionals taught adult students andragogically; in some cases they taught adult students pedagogically.

Predictors of colorectal cancer testing using the California Health Inventory Survey

AIM:To identify key variables associated with colon cancer testing using the 2009 California Health Inventory Survey(CHIS).METHODS:The CHIS has been conducted biennially since 2001 using a two-stage,geographically stratified random-digit-dial sample design to produce a representative sample of the entire State.For this study we used survey data from 2001-2009 inclusive.We restricted our analysis to White,Black,and Hispanic/Latinos aged 50-80 years.Weighted data was used to calculate the proportion of participants who underwent some form of colon cancer testing(colonoscopy,flexible sigmoidoscopy or fecal occult blood testing) within the previous 5 years stratified by race/ethnicity.For inferential analysis,boot-strapping with replacement was performed on the weighted sample to attain variance estimates at the 95%CI.For mean differences among categories we used t-tests and for comparisons of categorical data we used Pearson's χ 2.Binary logistic regression was used to identify independent variables associated with undergoing some form of testing.Trend analysis was performed to determine rates of testing over the study period stratified by race.RESULTS:The CHIS database for 2009 had 30 857 unique respondents corresponding to a weighted sample size of 10.6 million Californians.Overall,63.0%(63.0-63.1) underwent a colon cancer test within the previous 5 years;with 70.5%(70.5%-70.6%) of this subset having undergone colonoscopy.That is 44.5%(44.4%-44.5%) of all individuals 50-80 underwent colonoscopy.By multivariable regression,those tested were more likely to be male(OR = 1.06;95%CI:1.06-1.06),Black(OR = 1.30;95%CI:1.30-1.31),have a family member with colon cancer(OR = 1.71;95%CI:1.70-1.72),and have health insurance(OR = 2.71;95%CI:2.70-2.72).Progressive levels above the poverty line were also associated with receiving a test(100%-199%:1.21;1.20-1.21),(200%-299%:1.41;1.40-1.42),(> 300:1.69;1.68-1.70).The strongest variable was physician recommendation(OR = 3.90;95%CI:3.88-3.91).For the Hispanic/Latino group,additional variables associated with testing were success of physician-patient communication(OR = 2.44;95%CI:2.40-2.48) and naturalized citizenship status(OR = 1.91;95%CI:1.89-1.93).Trend analysis demonstrated increased colon cancer testing for all racial/ethnic subgroups from 2001-2009 although the rate remained considerably lower for the Hispanic/Latino subgroup.CONCLUSION:Using CHIS we identified California citizens most likely to undergo colon cancer testing.The strongest variable associated with testing for all groups was physician recommendation.

The tempo-spatial evolution characteristics of the load/unload response ratio before strong earthquakes in California of America and its predicting implications

In this paper, the tempo-spatial evolution characteristics of the load/unload response ratio (namely LURR or Y value) before strong earthquakes with magnitude over 6 during 1976~1994 in California of America are studied in detail. The results show that there appear some high-Y regions cohering with the regional tectonic trend in a great area 3~4 years before strong earthquakes and these high-Y regions migrate from the periphery to the epicenter region at a speed of tens of kilometers per year. The load/unload response ratio (LURR) anomalies near the epicenter region characterizes a type of (ascend ? descend( and appear and increase steeply until one year or less before most earthquakes. (Positive( earthquakes form usually a concentration area; in and near which the main shock occurs. We have analyzed the different and same characters of earthquakes between California of American and the Chinese mainland. Basing on these results, we discuss the approach and method how to predict and estimate the three parameters (place, time and magnitude) of a strong earthquake in California of American by applying the characteristics of the LURR.

California成年人汉语普通话/l/音位变体发音缺陷探究

使用抽样调查法、观察法、实验法、访问法,研究了来自California的成年本族语者发汉语普通话中的/l/音位的各个变体时的发音缺陷,发现他们的通病在于发音时舌尖的中部呈松弛状态,舌身在发音的除阻阶段整体位置有所移动而未固定。其中白种人和黄种人的缺陷程度高于黑种人,白种人和黄种人有软腭化的习惯,而黑种人没有。在充分探究了原因之后,为他们制定了符合各自实际情况的教学策略。