On the thermal budget of Pahoehoe lava flows

In this thesis I investigate some aspects of the thermal budget of pahoehoe lava flows. This is done with a combination of general field observations, quantitative modeling, and specific field experiments. The results of this work apply to pahoehoe flows in general, even though the vast bulk of the work has been conducted on the lavas formed by the Pu'u 'O'o - Kupaianaha eruption of Kilauea Volcano on Hawai'i. The field observations rely heavily on discussions with the staff of the United States Geological Survey's Hawaiian Volcano Observatory (HVO), under whom I labored repeatedly in 1991-1993 for a period totaling about 10 months.

The quantitative models I have constructed are based on the physical processes observed by others and myself to be active on pahoehoe lava flows. By building up these models from the basic physical principles involved, this work avoids many of the pitfalls of earlier attempts to fit field observations with "intuitively appropriate" mathematical expressions. Unlike many earlier works, my model results can be analyzed in terms of the interactions between the different physical processes. I constructed models to: (1) describe the initial cooling of small pahoehoe flow lobes and (2) understand the thermal budget of lava tubes.

The field experiments were designed either to validate model results or to constrain key input parameters. In support of the cooling model for pahoehoe flow lobes, attempts were made to measure: (1) the cooling within the flow lobes, (2) the amount of heat transported away from the lava by wind, and (3) the growth of the crust on the lobes. Field data collected by Jones [1992], Hon et al. [1994b], and Denlinger [Keszthelyi and Denlinger, in prep.] were also particularly useful in constraining my cooling model for flow lobes. Most of the field observations I have used to constrain the thermal budget of lava tubes were collected by HVO (geological and geophysical monitoring) and the Jet Propulsion Laboratory (airborne infrared imagery [Realmuto et al., 1992]). I was able to assist HVO for part of their lava tube monitoring program and also to collect helicopterborne and ground-based IR video in collaboration with JPL [Keszthelyi et al., 1993].

The most significant results of this work are (1) the quantitative demonstration that the emplacement of pahoehoe and 'a'a flows are the fundamentally different, (2) confirmation that even the longest lava flows observed in our Solar System could have formed as low effusion rate, tube-fed pahoehoe flows, and (3) the recognition that the atmosphere plays a very important role throughout the cooling of history of pahoehoe lava flows. In addition to answering specific questions about the thermal budget of tube-fed pahoehoe lava flows, this thesis has led to some additional, more general, insights into the emplacement of these lava flows. This general understanding of the tube-fed pahoehoe lava flow as a system has suggested foci for future research in this part of physical volcanology.

Euskalaritzaren historiaren ikerketa-norabideak: zenbait proposamendu

[EN] The aim of this paper is to propose some lines of investigation and new methods that can be followed in order to increase our knowledge of the History of Basque Linguistics. The main claim put forward here is that we must profit from the new methodological innovations developed by the H istoriography of Linguistics since the 60's. In the first section, different aspects are mentioned of the relevance of the study of Basque Linguistic Historiography. The second section comments on the boom of the Historiography of Linguistics from the 60's, its causes and its consequences; furthermore, it reports on the methodological models emerged from the discussions since then (as shown in works by Koerner, Swiggers, and many others). The third section points out some difficulties and challenges of the study of the History of Basque Linguistics, and suggests both some priorities for that study and possible lines of investigation. In order to illustrate the different points made throughout the paper, the reader is referred, when possible, to examples chosen from recent investigations or from future topics of research.

Huerto urbano comunitario

El proyecto que se expone a continuación consiste en la creación de un Huerto Urbano Comunitario. Los criterios en los que se sustenta son; la soberanía alimentaria, el desarrollo comunitario y la sostenibilidad. Se pretende con él que los participantes adquieran formación y conciencia crítica sobre los modos de producción y consumo agrícola. Para ello se estimulará la implicación mediante dinámicas de grupo, charlas, proyecciones, excursiones, debates, etc. Sin olvidarnos en ningún momento del trabajo manual y todas las acciones necesarias para la creación del propio huerto.

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