Pattern Dynamics and Forecast Methods in Seismically Active Regions

—Large, extended fault systems such as those in California demonstrate complex space-time seismicity patterns, which include repetitive events, precursory activity and quiescence, and aftershock sequences. Although the characteristics of these patterns can be qualitatively described, a systematic quantitative analysis remains elusive. Our research suggests that a new pattern dynamics methodology can be used to define a unique, finite set of seismicity patterns for a given fault system. In addition, while a long-sought goal of earthquake research has been the reliable forecasting of these events, very little progress has been made in developing a successful, consistent methodology. In this report, we document the discovery of systematic space-time variations in seismicity from southern California using a new technique. Here we present examples of this analysis technique on data obtained prior to events in seismically active areas that show coherent regions associated with the future occurrence of major earthquakes in the same areas. These results strongly support the hypothesis that seismic activity is highly correlated across many space and time scales within large volumes of the earth's crust.     

Assessment of the feasibility of utilizing Landsat for detection and monitoring of landfills in a statewide GIS

Use of satellite data could be beneficial and cost effective in detecting and monitoring landfills in a state-wide geographic information system (GIS). To assure the feasibility of this approach, multitemporal Landsat data were used to detect several selected active and inactive landfills in central and southwest Missouri. The landfills were visually delineated from aerial photography of approximately the same two dates. A classification procedure based on homogeneity of the digital numbers was performed on each landfill scene for each time period using four spectral bands: two visible, one near-infrared, and one mid-infrared. The mid-infrared band proved more useful in delineating landfills, especially when spectral change was compared to the near-infrared band. The active landfills were spectrally different from surrounding land cover as were the two landfills which closed after the collection of the first Landsat scene. These landfills showed considerable areal change between the two selected time periods as verified by the aerial photographs. The inactive landfills were more difficult to discern from surrounding land cover types because they were grass covered and spectrally similar to pasture. Consequently, areal change could not be assigned to these older landfills because the reclamation process was practically complete.     

Largest dinosaur tracksite in China(Cretaceous,Zhaojue area,Sichuan Province): On the verge of destruction

The Zhaojue(ZJ) tracksites represent multiple steeply-inclined, track-bearing exposures in the clastic Feitianshan Formation of Sichuan Province that have been sequentially, excavated, mapped, expanded and destroyed, by quarrying,erosion or collapse, for almost three decades. The quarried area extends for more almost 1.0 km from north to south and ～0.5 km from east to west. Four important track-bearing surfaces have been identified and identified as ZJ-I, ZJ-II,ZJ-IIN and ZJ-III, some of which are newly exposed surfaces or expanded surfaces that were previously partially described. Others represent surfaces lost since they were first reported in papers published in 2014–2016. The ZJ-II site represents a hugely expanded continuation of a much smaller track-bearing surface described in 2014. It was mapped using drone technology, and now represents the largest tracksite in China, with a minimum count of 933 recognizable tracks, and the longest recorded sauropod and ornithopod trackways from China(～80 m and ～52 m respectively), which also reveal a pronounced change in the direction of trackmaker movement. The ZJ-II surface represents the best Zhaojue paleo-census sample giving a count of 68 individuals from 61 trackways(37 ornithopod, 10 theropod, 14 sauropod) and isolated tracks(representing 7 individuals). Thus, ornithopods(both large and small trackmakers) represent ～54% of the total number of trackways. The smaller ZJ-III surface was mapped using traditional methods, and reveals at least 6 ornithopod-and 4 theropod trackways. Both the ZJ-II and ZJ-III surfaces reveal parallel ornithopod trackways suggestive of social or gregarious behavior. The combined data from all four Zhaojue surfaces reveal a total of 1928 tracks, and include a few previously reported pterosaurs and theropod swim tracks. The Zhaojue quarry complex provide a good example of multiple track-bearing sites(surfaces) that require long term study and monitoring to extract as much trackway data as possible before in situ physical evidence is lost.     

A dendroclimatological study of east- and west-facing slopes in mountainous areas subjected to strong air pollution (the Sudetes,Central Europe)

The Sudetes Mountains (Central Europe) were under a particularly intense long-term air pollution load during the 1970s and 1980s. Intense industrial activity in this area led to large-scale forest dieback and reductions in tree growth rates, potentially limiting the use of tree-ring data from this region in dendroclimatic research. In this paper, ring-width chronologies were constructed for 493 Norway spruce trees (Picea abies L. Karst.) from 17 sampling sites within five major mountain ranges in the Sudetes Mountains of Poland. Growth-climate response data indicate that April?July temperatures are the main factor affecting radial growth of trees in the study area. Our data also indicate the strong influence of slope aspect on temperature signal strength. The lowest correlation values were obtained for sites located on western slopes with effective fog deposition, which are strongly affected by pollution. An appropriate sampling strategy resulted in the creation of a temperature-sensitive proxy record (rAMJJ = 0.70), exceptional for areas under strong pressure from human activity. Based on a regional master chronology, growing season (April?July) temperatures over the past 200 years were then reconstructed. Four warm and four cold periods were distinguished and compared with other reconstructions and long-term instrumental data.     

Solar flares at submillimeter wavelengths

We discuss the implications of the first systematic observations of solar flares at submillimeter wavelengths, defined here as observing wavelengths shorter than 3 mm (frequencies higher than 0.1 THz). The events observed thus far show that this wave band requires a new understanding of high-energy processes in solar flares. Several events, including observations from two different observatories, show during the impulsive phase of the flare a spectral component with a positive (increasing) slope at the highest observable frequencies (up to 405 GHz). To emphasize the increasing spectra and the possibility that these events could be even more prominent in the THz range, we term this spectral feature a “THz component”. Here we review the data and methods, and critically assess the observational evidence for such distinct component(s). This evidence is convincing. We also review the several proposed explanations for these feature(s), which have been reported in three distinct flare phases. These data contain important clues to flare development and particle acceleration as a whole, but many of the theoretical issues remain open. We generally have lacked systematic observations in the millimeter-wave to far-infrared range that are needed to complete our picture of these events, and encourage observations with new facilities.     

The wider context of the Lower Jurassic Toarcian oceanic anoxic event in Yorkshire coastal outcrops,UK

The Toarcian Oceanic Anoxic Event (T-OAE, ～183 Ma) was characterized by enhanced carbon burial, a prominent negative carbon-isotope excursion (CIE) in marine carbonate and organic matter, and numerous geochemical anomalies. A precursor excursion has also been documented at the Pliensbachian/Toarcian boundary, but its possible causes are less constrained. The T-OAE is intensively studied in the Cleveland Basin, Yorkshire, UK, whose sedimentary deposits have been litho-, bio- and chemostratigraphically characterised. Here, we present new elemental data produced by hand-held X-ray fluorescence analysis to test the expression of redox-sensitive trace metals and detrital elements across the upper Pliensbachian to mid-Toarcian of the Cleveland Basin. Detrital elemental concentrations (Al, Si, Ti, Zr) are used as proxies for siliciclastic grain content and thus, sea-level change, which match previous sequence stratigraphic interpretations from the Cleveland Basin. The timescale of the event is debated, though our new elemental proxies of relative sea level change show evidence for a cyclicity of 350 cm that may be indicative of ～405 kyr eccentricity cycles in Yorkshire. Trends in total organic carbon and redox-sensitive elements (S, Fe, Mo, As) confirm scenarios of widespread ocean deoxygenation across the T-OAE. The correlation of comparable trends in Mo across the T-OAE in Yorkshire and the Paris Basin suggests a similar oceanic drawdown of this element accompanying widespread anoxia in the two basins. Data from Yorkshire point to a transgressive trend at the time of the Mo drawdown, which contradicts the “basin restriction” model for the euxinic conditions that characterise the CIE interval.     

The relevance of Old World archeology to the first entry of man into the New World

Archeological evidence from the USSR suggests that cultural adaptations to the most rigorous (most continental) environments of northern Eurasia were not achieved until 35–40,000 BP. This presumably sets an absolute basement date for the entry of man into Alaska through the region of Beringia. The absence of evidence for pre-14,000 yr old man in the 48 adjacent United States comparable in any sense to the evidence that has been developed for man prior to 14,000 y.a. in the Old World suggests that movement south out of Alaska only occurred after 14,000 BP.     

Quiescent radio emission of RS CVn binary systems

It is shown that the quiescent radio emission observed in some RS Vc binary systems cannot be ascribed to the same thermal electrons population responsible for the X-ray emission. An alternative explanation to account for the observed correlation between X-ray and radio luminosity is suggested.Paper presented at the 11th European Regional Astronomical Meetings of the IAU on New Windows to the Universe, held 3–8 July, 1989, Tenerife, Canary Islands, Spain.     

Regression model for generating time series of daily precipitation amounts for climate change impact studies

The precipitation amounts on wet days at De Bilt (the Netherlands) are linked to temperature and surface air pressure through advanced regression techniques. Temperature is chosen as a covariate to use the model for generating synthetic time series of daily precipitation in a CO₂ induced warmer climate. The precipitation-temperature dependence can partly be ascribed to the phenomenon that warmer air can contain more moisture. Spline functions are introduced to reproduce the non-monotonous change of the mean daily precipitation amount with temperature. Because the model is non-linear and the variance of the errors depends on the expected response, an iteratively reweighted least-squares technique is needed to estimate the regression coefficients. A representative rainfall sequence for the situation of a systematic temperature rise is obtained by multiplying the precipitation amounts in the observed record with a temperature dependent factor based on a fitted regression model. For a temperature change of 3°C (reasonable guess for a doubled CO₂ climate according to the present-day general circulation models) this results in an increase in the annual average amount of 9% (20% in winter and 4% in summer). An extended model with both temperature and surface air pressure is presented which makes it possible to study the additional effects of a potential systematic change in surface air pressure on precipitation.