Studies supporting an upper-atmosphere chemical release program. Part I - Experimental studies on chemiluminescence. Part II - A model of releases leading to upper-atmospheric chemi-ion formation Final report, May 1965 - May 1966

Chemiluminescence of chemical compounds released in upper atmosphere and model of releases leading to upper atmospheric chemi-ionizatio

Possible coupling between climatically induced lake level change, volcanic eruptions and seismotectonic activation in the Rukwa-Rungwe-Nyasa rift, SW Tanzania

The Rukwa rift basin is presently a closed hydrogeological depression containing a shallow lake (max 20 me deep) with its surface at an altitude around 810 m above sea level. Lacustrine terraces and paleo-shorelines are known up to 980 m above sea level, an altitude at which it reach the overflow sill towards Lake Tanganyika. Both Lakes Tanganyika and Nyasa (Malawi) are presently overflowing, but as their lake level fluctuates, they have been disconnected from their outlet in the recent past. High resolution seismic profiling in both Lakes Rukwa and Malawi has show the presence of active fault systems underneath the lake floor. Some of these fault systems appear to have had a cyclic activity, with alternating periods of high tectonic activity/sedimentation and periods of tectonic quiescence. The accommodation zone between Lake Rukwa and Nyasa is occupied by the Rungwe volcanic Province, with the Ngozi, Rungwe and Kiejo volcanoes presenting signs of recent volcanic activity. The Rungwe Province is cross-cut by several directions of faults, which clearly control the location of the volcanic vents.In our work, we reviewed the available data on recent (Late Pleistocene – Holocene) volcanic eruptions, in the Rungwe area itself, in the drill cores from the surrounding lakes and from aerial observations up to 300 km away from the Rungwe Province. We performed morphotectonic and paleoseismic investigations of the Kanda fault, a major normal fault between lakes Rukwa and Tanganyika. We investigated lacustrine deposits of the Rukwa basin corresponding to the two last cycles of high lake level. The chronological framework was established using 30 new radiocarbon dating and the most prominent volcanic tephra layers were used as a reference in the correlations. The results are still preliminary, but a good correlation already appear between climatically induced lake level change (in Lake Rukwa), seismo-tectonic activation of the regional fault network (underneath Lake Rukwa and the Kanda fault between Lakes Rukwa and Tanganyika) and the timing of the recent strong volcanic eruptions in the Rungwe Volcanic Province since the last 40.000 years. This relation is explained taking into account that Lake Rukwa is very sensitive to climate change as it occupies a flat depression and its overflow outlet is 180 m above its present-day level. Its lake level rises rapidly when the climate becomes more humid as it was the case during the Last Glacial Maximum and during the Younger Dryas event. Increase in lake level means increasing of the load in the basin and perturbation of the ambient tectonic stresses. In most of the Rukwa rift, the tectonic stress is of extensional (normal faulting) regime, with the maximum principal stress axis (sigma 1) subvertical. In these conditions, increasing the vertical load will increase the shear stress on the existing normal faults, triggering (seismogenic) normal faulting deformation. As the architecture of the active volcanoes in the Rungwe Province is tectonically controlled, activation of the faults, together with a greater pressure of water in the tectonic discontinuities are likely to trigger large volcanic eruptions, strongly explosive

Synchronisation of sedimentary records using tephra : a postglacial tephrochronological model for the Chilean Lake District

Well-characterised tephra horizons deposited in various sedimentary environments provide a means of synchronising sedimentary archives. The use of tephra as a chronological tool is however still widely underutilised in southern Chile and Argentina. In this study we develop a postglacial tephrochronological model for the Chilean Lake District (ca. 38 to 42 degrees S) by integrating terrestrial and lacustrine records. Tephra deposits preserved in lake sediments record discrete events even if they do not correspond to primary fallout. By combining terrestrial with lacustrine records we obtain the most complete tephrostratigraphic record for the area to date. We present glass geochemical and chronological data for key marker horizons that may be used to synchronise sedimentary archives used for palaeoenvironmental, palaeoclimatological and palaeoseismological purposes. Most volcanoes in the studied segment of the Southern Volcanic Zone, between Llaima and Calbuco, have produced at least one regional marker deposit resulting from a large explosive eruption (magnitude >= 4), some of which now have a significantly improved age estimate (e.g., the 10.5 ka Llaima Pumice eruption from Llaima volcano). Others, including several units from Puyehue-Cordon Caulle, are newly described here. We also find tephra related to the Cha1 eruption from Chaiten volcano in lake sediments up to 400 km north from source. Several clear marker horizons are now identified that should help refine age model reconstructions for various sedimentary archives. Our chronological model suggests three distinct phases of eruptive activity impacting the area, with an early-to-mid-Holocene period of relative quiescence. Extending our tephrochronological framework further south into Patagonia will allow a more detailed evaluation of the controls on the occurrence and magnitude of explosive eruptions throughout the postglacial

Lessons from Love-Locks: The archaeology of a contemporary assemblage

This document is the Accepted Manuscript version. The final, definitive version of this paper has been published in Journal of Material Culture, November 2017, published by SAGE Publishing, All rights reserved.Loss of context is a challenge, if not the bane, of the ritual archaeologist’s craft. Those who research ritual frequently encounter difficulties in the interpretation of its often tantalisingly incomplete material record. Careful analysis of material remains may afford us glimpses into past ritual activity, but our often vast chronological separation from the ritual practitioners themselves prevent us from seeing the whole picture. The archaeologist engaging with structured deposits, for instance, is often forced to study ritual assemblages post-accumulation. Many nuances of its formation, therefore, may be lost in interpretation. This paper considers what insights an archaeologist could gain into the place, people, pace, and purpose of deposition by recording an accumulation of structured deposits during its formation, rather than after. To answer this, the paper will focus on a contemporary depositional practice: the love-lock. This custom involves the inscribing of names/initials onto a padlock, its attachment to a bridge or other public structure, and the deposition of the corresponding key into the water below; a ritual often enacted by a couple as a statement of their romantic commitment. Drawing on empirical data from a three-year diachronic site-specific investigation into a love-lock bridge in Manchester, UK, the author demonstrates the value of contemporary archaeology in engaging with the often enigmatic material culture of ritual accumulations.Peer reviewe

Give peace a chance

How is it possible that people kill each other? And above all: how is it possible that people who are able to peacefully live with each other at one moment, can kill each other at another one? These are fundamental questions about the human condition – questions that religions, philosophers and scientists have been wanting to solve since times immemorial and that continue to fascinate us today (Browning 1998; Harrison 1995; Morris 2015). So you may perhaps be wondering why I am posing such deep and essential questions at the start of a lecture that is meant to tell you something about our prehistory

Give peace a chance

How is it possible that people kill each other? And above all: how is it possible that people who are able to peacefully live with each other at one moment, can kill each other at another one? These are fundamental questions about the human condition – questions that religions, philosophers and scientists have been wanting to solve since times immemorial and that continue to fascinate us today (Browning 1998; Harrison 1995; Morris 2015). So you may perhaps be wondering why I am posing such deep and essential questions at the start of a lecture that is meant to tell you something about our prehistory

The 600 yr eruptive history of Villarrica Volcano (Chile) revealed by annually laminated lake sediments

Lake sediments contain valuable information about past volcanic and seismic events that have affected the lake catchment, and they provide unique records of the recurrence interval and magnitude of such events. This study uses a multilake and multiproxy analytical approach to obtain reliable and high-resolution records of past natural catastrophes from similar to 600-yr-old annually laminated (varved) lake sediment sequences extracted from two lakes, Villarrica and Calafquen, in the volcanically and seismically active Chilean Lake District. Using a combination of micro-X-ray fluorescence (mu XRF) scanning, microfacies analysis, grain-size analysis, color analysis, and magnetic-susceptibility measurements, we detect and characterize four different types of event deposits (lacustrine turbidites, tephra-fall layers, runoff cryptotephras, and lahar deposits) and produce a revised eruption record for Villarrica Volcano, which is unprecedented in its continuity and temporal resolution. Glass geochemistry and mineralogy also reveal deposits of eruptions from the more remote Carran-Los Venados volcanic complex, Quetrupillan Volcano, and the Huanquihue Group in the studied lake sediments. Time-series analysis shows 112 eruptions with a volcanic explosivity index (VEI) >= 2 from Villarrica Volcano in the last similar to 600 yr, of which at least 22 also produced lahars. This significantly expands our knowledge of the eruptive frequency of the volcano in this time window, compared to the previously known eruptive history from historical records. The last VEI >= 2 eruption of Villarrica Volcano occurred in 1991. Based on the last similar to 500 yr, for which we have a complete record from both lakes, we estimate the probability of the occurrence of future eruptions from Villarrica Volcano and statistically demonstrate that the probability of a 22 yr repose period (anno 2013) without VEI >= 2 eruptions is <= 1.7%. This new perspective on the recurrence interval of eruptions and historical lahar activity will help improve volcanic hazard assessments for this rapidly expanding tourist region, and it highlights how lake records can be used to significantly improve historical eruption records in areas that were previously uninhabited

AmbientDB: P2P Data Management Middleware for Ambient Intelligence

The future generation of consumer electronics devices is envisioned to provide automatic cooperation between devices and run applications that are sensitive to people's likings, personalized to their requirements, anticipatory of their behavior and responsive to their presence. We see this `Ambient Intelligence' as a key feature of future pervasive computing. We focus here on one of the challenges in realizing this vision: information management. This entails integrating, querying, synchronizing and evolving structured data, on a heterogeneous and ad-hoc collection of (mobile) devices. Rather than hard-coding data management functionality in each individual application, we argue for adding highlevel data management functionalities to the distributed middleware layer. Our AmbientDB P2P database management system addresses this by providing a global database abstraction over an ad-hoc network of heterogeneous peers