Browsing by Subject "Iceland"
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Item Polarimetric SAR decomposition of temperate Ice Cap Hofsjokull, central Iceland(2010-08) Minchew, Brent Morton; Buckley, Sean M.; Hensley, ScottFully-polarimetric UAVSAR data of Hofsjokull Ice Cap, central Iceland, taken in June 2009 was decomposed using Pauli-based coherent decomposition as well as Cloude and H/A/alpha eigenvector-based decomposition methods. The goals of this research were to evaluate the effect of the near-surface conditions of temperate glaciers on polarized SAR data and investigate the potential of creating a model of the radar scattering mechanisms based on the decomposed elements and local temperature. The results of this data analysis show a strong relationship between the Pauli and H/A/alpha decomposition elements and the near-surface conditions. Fitting curves to the normalized Pauli decomposition elements shows consistent trends across several spatially independent regions of the ice cap suggesting that the Pauli elements might be useful for modeling the scattering mechanisms of temperate ice with various surface conditions.Item Sills and laccoliths(2009-04) Barker, Daniel S.Item The impact of public participation in constitution making(2018-10-09) Hudson, Alexander Edward; Elkins, Zachary, 1970-; Brinks, Daniel; Jacobsohn, Gary; Levinson, Sanford; Wlezien, ChristopherPublic participation has long been an important element of constitution-making processes. It increasingly takes place early in the process, ostensibly offering citizens an opportunity to contribute directly to the text of their new national charter. Despite growth in the use and political prominence of participatory mechanisms, we know little about their effects. This dissertation argues that the impact of public participation on the text of constitutions is small in almost all cases, but that there are systematic ways in which this impact varies. Specifically, the variation in the effects of public participation is for the most part determined by the strength of political parties in the constitution-making process. In constitution-making bodies where there are strong parties, there is very little room for effective public participation. In such systems, there will be almost no impact from public participation, even where significant amounts of time and money are devoted to facilitating it. Conversely, in constitution-making bodies where political parties are not present, or where parties are weak, there will be a greater impact from public participation, as drafters are unprotected from pressure groups and also more reliant on the information they provide. I further argue that the informational challenges of assessing the impact of public participation prevent the majority of participants from determining whether or not the participation program was effective. Thus, public participation programs can serve to increase public support for a constitution even when drafters do not make any changes to the content of the constitution in response to public input. This theory is tested through studies of three cases of highly participatory constitution making. Keeping the level and means of participation relatively constant, the three cases have been chosen to include a case with strong parties (South Africa), a case with weak parties (Brazil), and a case where the constitution was drafted without parties (Iceland). As predicted, the South African case shows negligible impacts from public participation, Brazil has some scattered impacts, and Iceland shows high levels of impact. The findings here demonstrate that the expected relationships between citizens, political parties, and interest groups exist even in constitution-making processes. Moreover, it shows that there are trade-offs between stability, textual quality, and more effective public input.Item Timeline reconstruction of Holocene jökulhlaups along the Jökulsá á Fjöllum channel, Iceland(2016-05) Wells, Greta Hoe; Luzzadder-Beach, Sheryl; Beach, Timothy P; McKinney, Daene CThe Jökulsá á Fjöllum is Iceland’s second longest river, draining from the Vatnajökull ice cap and winding for over 200 km through the eastern highlands before emptying into the Arctic Ocean. Hydrothermal activity and subglacial eruptions beneath Vatnajökull generate enormous quantities of meltwater, which can drain catastrophically in outburst floods, known as jökulhlaups. Jökulhlaups have flowed through the Jökulsá á Fjöllum channel throughout the Holocene, but intense debate exists over their timing and magnitude. While previous studies report a peak flood discharge of 0.9 x 106 m3 s-1, Howard et al. (2012) found evidence of a peak discharge of 2.2 x 107 m3 s-1, which would make this the largest known flood on Earth. This project seeks to test Howard et al.’s (2012) hypothesis and, more broadly, to reconstruct a timeline of Holocene jökulhlaups along the Jökulsá á Fjöllum. First, it reviews current literature and research on Icelandic geology and megafloods; second, it reviews and critiques previous research methods and evidence of Holocene jökulhlaups along the channel, while also presenting new geomorphologic and geochronological evidence from field work in August 2015; and finally, it sets up a framework for future research and explores unanswered questions regarding the history of Holocene jökulhlaups along the Jökulsá á Fjöllum.Item Viscous lava flows(2009-03) Barker, Daniel S.