Reconstructing palaeoprecipitation from an active cave flowstone

Several drill cores were obtained from a laminated, actively forming flowstone from a shallow cave in Austria. Highly resolved petrographic and geochemical analyses combined with multi‐annual cave monitoring reveal a distinct sensitivity of flowstone growth and composition to late Holocene meteoric precipitation. The regular sub‐millimetre‐scale lamination consists of thicker, translucent laminae and thinner (organic) inclusion‐rich laminae. There is also a macroscopic millimetre‐scale banding of darker and lighter bands comprising several laminae. Stable isotope analyses of drill cores and modern calcite precipitates show a pronounced positive covariation of δ¹³C and δ¹⁸O values indicative of kinetic isotope effects. Comparing the isotope values with petrography shows gradual changes across several of the annual laminae, i.e. changes of several per mille on a multi‐annual to decadal timescale. The stable isotope and trace‐element composition, as well as the flowstone petrography, are mainly controlled by the variable drip‐water discharge controlling the water‐film thickness and water residence time on the flowstone surface and consequently the intensity of CO₂‐degassing, kinetic isotope enrichment and concomitant calcite precipitation. Drill core PFU6 provides an isotope record of the last ca. 3000 years at near‐annual resolution. A distinct phase of low C and O isotope values – interpreted as increased discharge and hence higher meteoric precipitation – occurred from ca. 300 to 140 a b2k (second half of the Little Ice Age) and another wet interval occurred around 700 a, corresponding to reported Medieval glacier advances. The Roman Warm Period was also dominated by relatively wet conditions, although significant decadal variability prevailed. Increased precipitation further characterized the intervals from ca. 2480 to 2430 and 2950 to 2770 a. Dry conditions persisted during the Medieval Climate Anomaly, although this trend towards reduced precipitation started earlier. The highest C isotope values of the last 2 ka are recorded around 750 a and another dry phase is centred at 1480 a. This new record shows that inter‐annual to decadal oscillations are a dominant mode of variation during the last 3 ka in the Alps. Copyright © 2011 John Wiley & Sons, Ltd.     

Studies on the contribution of some geological factors to seismic hazard

The present study is primarily meant to make a separation of the amplification effects in the intensity distribution within the macroseismic field function of their different causes, i.e. the activation of some regional tectonic lines during the seismic motion and local seismogeological conditions.With this end in view, the methodology used consists of filtering the direct macroseismic observations by means of the weighted mean-values method and outlining the regional and local field anomalies.The regional anomaly map of the macroseismic field of the 4 March 1977 Vrancea earthquake, including the southern and south-eastern part of the Outer Carpathian Zone, has been analyzed. Some dislocations, located in the platform basement, which functioned as seismic energy amplifiers during the event, have been identified.The results obtained can be used in seismotectonic and microzoning studies.Paper presented at the 21st General Assembly of the European Seismological Commission, Sofia, 1988.     

A high-resolution speleothem proxy record of the Late Glacial in the European Alps: extending the NALPS19 record until the beginning of the Holocene

Previous research has shown that speleothems from the northern rim of the European Alps captured submillennial-scale climate change during the last glacial period with exceptional sensitivity and resolution, mimicking Greenland ice-core records. Here we extend this so-called NALPS19 record across the Late Glacial using two stalagmites which grew continuously into the Holocene. Both specimens show the same high-amplitude δ¹⁸O signal as Greenland ice cores down to decadal resolution. The start of the warming at the onset of the equivalent of Greenland Interstadial (GI) GI-1e at 14.66 ± 0.18 ka agrees with the North Greenland Ice Core Project (NGRIP) (14.64 ± 0.28 ka) and comprised a temperature rise of about 5–6 °C. The transition from the equivalent of GI-1a into the equivalent of Greenland Stadial (GS) GS-1 (broadly equivalent to the Younger Dryas) commenced at 13.02 ± 0.13 ka which is consistent with NGRIP (12.80 ± 0.26 ka) within errors. The onset of the Holocene started at 11.78 ± 0.14 ka (11.65 ± 0.10 ka at NGRIP) and involved a warming of about 4–5 °C. In contrast to δ¹⁸O, δ¹³C values show no response to (sub)millennial climate shifts due to strong rock-buffering and only record a long-term trend of soil development starting with the rapid warming at 14.7 ka.     

Estimating the upper limit of prehistoric peak ground acceleration using an in situ,intact and vulnerable stalagmite from Plavecká priepast cave (Detrekői-zsomboly), Little Carpathians,Slovakia—first results

Earthquakes hit urban centres in Europe infrequently, but occasionally with disastrous effects. Obtaining an unbiased view of seismic hazard (and risk) is therefore very important. In principle, the best way to test probabilistic seismic hazard assessments (PSHAs) is to compare them with observations that are entirely independent of the procedure used to produce PSHA models. Arguably, the most valuable information in this context should be information on long-term hazard, namely maximum intensities (or magnitudes) occurring over time intervals that are at least as long as a seismic cycle. The new observations can provide information of maximum intensity (or magnitude) for long timescale as an input data for PSHA studies as well. Long-term information can be gained from intact stalagmites in natural caves. These formations survived all earthquakes that have occurred over thousands of years, depending on the age of the stalagmite. Their ‘survival’ requires that the horizontal ground acceleration (HGA) has never exceeded a certain critical value within that time period. Here, we present such a stalagmite-based case study from the Little Carpathians of Slovakia. A specially shaped, intact and vulnerable stalagmite in the Plavecká priepast cave was examined in 2013. This stalagmite is suitable for estimating the upper limit of horizontal peak ground acceleration generated by prehistoric earthquakes. The critical HGA values as a function of time going back into the past determined from the stalagmite that we investigated are presented. For example, at the time of Jók? event (1906), the critical HGA value cannot have been higher than 1 and 1.3 m/s² at the time of the assumed Carnuntum event (～340 AD), and 3000 years ago, it must have been lower than 1.7 m/s². We claimed that the effect of Jók? earthquake (1906) on the location of the Plavecká priepast cave is consistent with the critical HGA value provided by the stalagmite we investigated.The approach used in this study yields significant new constraints on the seismic hazard, as tectonic structures close to Plavecká priepast cave did not generate strong earthquakes in the last few thousand years. The results of this study are highly relevant given that the two capitals, Vienna and Bratislava, are located within 40 and 70 km of the cave, respectively.     

First Satellite Measurements of Carbon Dioxide in the Earth’s Atmosphere (From the SI-1 Spectrometer Aboard the Meteor Satellite in 1979)

Izvestiya, Atmospheric and Oceanic Physics - Spectral measurements of the outgoing thermal IR radiation carried out in 1977 and 1979 (SI-1 instrument, Meteor satellite) are used for estimating the...     

A new bivariate Gamma distribution generated from functional scale parameter with application to drought data

Univariate and bivariate Gamma distributions are among the most widely used distributions in hydrological statistical modeling and applications. This article presents the construction of a new bivariate Gamma distribution which is generated from the functional scale parameter. The utilization of the proposed bivariate Gamma distribution for drought modeling is described by deriving the exact distribution of the inter-arrival time and the proportion of drought along with their moments, assuming that both the lengths of drought duration (X) and non-drought duration (Y) follow this bivariate Gamma distribution. The model parameters of this distribution are estimated by maximum likelihood method and an objective Bayesian analysis using Jeffreys prior and Markov Chain Monte Carlo method. These methods are applied to a real drought dataset from the State of Colorado, USA.