Att tidigt kunna detektera samt åtgärda sättningar och deformationer är viktigt inom exempelvis bygg-, anläggnings- och gruvindustrin för att kontrollera att verksamheten inte påverkar närliggande områden och strukturer. UAV (Unmanned Aerial Vehicle) fotogrammetri är en lämplig metod för att utföra upprepade mätningar i svårtillgänglig miljö där sättningar kan uppkomma. Syftet med denna studie har varit att undersöka möjligheten till att detektera sättningar med UAV fotogrammetri samt att jämföra direkt och indirekt georeferering. Detta har undersökts genom att ett antal objekt har använts till att simulera sättningar med förändringar på centimeternivå. Området som studien utfördes på flögs över med en fotogrammetrisk UAV i två epoker varav den första epoken var innan sättning och den andra epoken var efter en simulerad sättning av objekten. Punkter markerades på objekten vilka mättes in med totalstation för båda epokerna och dessa mätningar användes som referensvärden (hädanefter kallat True Value). Bearbetning skedde därefter i två programvaror: Agisoft Metashape och Leica Infinity. I Metashape skapades punktmoln för båda epokerna indirekt georefererade med markstödpunkter. I Infinity skapades punktmoln för båda epokerna direkt georefererade med Nätverks-RTK (N-RTK). Punktmolnens avvikelser mot kontrollpunkter kontrollerades. Koordinater för markeringarna på objekten extraherades och jämfördes med koordinater inmätta med totalstation. Resultatet av bearbetningen blev fyra olika punktmoln. I de indirekt georefererade punktmolnen var det möjligt att detektera deformeringar på centimeternivå. Det var däremot inte möjligt i de direkt georefererade punktmolnen då de var påverkade av ett systematiskt fel i höjd. De två programvarornas arbetsgång och resultat jämfördes även mot varandra och där kan det konstateras att om de två programvarorna båda har höga systemkrav så var Leica Infinity betydligt mer krävande både vad gäller hårdvara och tidsåtgång än Agisoft Metashape. De slutsatser vi kan dra utifrån denna studie är att N-RTK ännu inte är en tillräckligt bra georefereringsmetod när låga osäkerheter efterfrågas. I detta fall är indirekt georeferering eller registrering av punktmolnen med hjälp av ICP (Iterative Closest Point) algoritmer att föredra. Det är också viktigt att generera punktmoln med en så hög punkttäthet som möjligt för att kunna göra noggranna mätningar i molnen. / The early detection and measure of subsidence and deformations is important within construction-, civil engineering and the mining industry to control whether the operations affect nearby areas and structures. UAV (Unmanned Aerial Vehicle) photogrammetry is a suitable method to conduct repeated measurements in environments which is hard to access where subsidence can occur. The purpose of this study has been to investigate the possibility of detecting subsidence with UAV photogrammetry and compare direct and indirect georeferencing. This has been investigated by using several objects to simulate subsidence at centimeter level. The area where the study was conducted was flown over with a photogrammetric UAV in two epochs of which the first epoch was before subsidence and the second epoch was after a simulated subsidence of the objects. Points was marked on the objects who were measured with a total station for both epochs and these measurements was used as reference values (hereafter called True Value). Processing was thereafter done in two different software: Agisoft Metashape and Leica Infinity. In Metashape point clouds was created for both epochs indirectly georeferenced with ground control points. In Infinity point clouds was created for both epochs directly georeferenced with Network-RTK (N-RTK). The deviations of the point clouds towards checkpoints were verified. Coordinates of the markings on the objects was extracted and compared against coordinates measured with total station. The photogrammetric processing resulted in four different point clouds. In the indirectly georeferenced pointclouds it was possible to detect deformations at centimeterlevel. This was however not possible using the directly georeferenced pointclouds as they were affected by a systematic error in heigth. The workflow and the resulting point clouds from the two different software was also compared to each other and by that it was established that even though they both have high system requirements the Leica Infinity software was much more demanding and additionally time consuming. The conclusion from this study is that N-RTK is not yet a satisfactory method for georeferencing when low uncertainties are required. In this case, indirect georeferencing or registration of the point clouds with ICP (Iterative Closest Point) algorithms is to be preferred. It is also important to create point clouds with the highest density possible to be able to make exact measurements.

Die Nutzung von Flächen mit künstlichen oder natürlichen Hohlräumen im Unter- und Baugrund ist mit erhöhten Risiken behaftet, weil Bauwerke durch unerwünschte Deformationen des Baugrundes in Mitleidenschaft gezogen werden können. Zur theoretischen Analyse eines Tagesbruchvorganges über einen zusammenbrechenden Hohlraum in praktischen Aufgabenstellungen auf Standorten mit mehreren Schichten kann die ”Allgemeine Hohlraum-Bruchmassen-Bilanz-Methode” mit einer stark eingegrenzten Anzahl von Eingangsparametern genutzt werden. In einer rechnerischen Tagesbruchprognose können sowohl die Eingangsgrößen der theoretischen Modellierung eines Tagesbruchvorganges als auch die Größe prognostizierter Tagesbruchvolumina als Zufallsvariable angesehen werden. Die Random-Set-Theorie bietet eine praktikable Möglichkeit, die stochastische Natur des Tagesbruchvorganges mit einem begrenzten rechnerischen Aufwand theoretisch zu fassen. Die berechneten Tagesbruchvolumina und die zugehörigen Eintrittswahrscheinlichkeiten können als Grundlage der Risikobewertung von zu schützenden Objekten herangezogen werden. / The use of sites with artificial or natural openings in the underground includes an elevated technical risk, as constructions can be constrained due to unplanned deformations of the subsoil. To the theoretical analysis of pothole subsidence in practical settings on a layered site, the ”General Failure Mass Volume Balance Method”can be applied with a low number of input parameters. Both the input values of a theoretical model for pothole subsidence analysis and the volume of prognosed surface failures can be regarded as random variables. The randomset- theory offers a practical solution to include the stochastic nature of the pothole subsidence process into a theoretical model with limited required computational effort. The prognosed volumina and the corresponding probabilities of occurrence can be used for a risk analysis of protected objects on sites with expected pothole subsidence.

Am Beispiel des Kavernenfeldes Epe, das mit seinen aktuell 76 Erdgaskavernen einen Anteil von 15% an den gesamtdeutschen Untergrundgasspeichern hat, soll gezeigt werden, wie das Markscheidewesen helfen kann, die „licence to operate“ bestehender Betriebe zu erhalten und den Genehmigungsprozess von Neuprojekten zu unterstützen. Bergbau ist nahezu immer mit Bodenbewegungen verbunden, der Betrieb von Salzkavernen zur Solegewinnung und Untergrundspeicherung macht hier keine Ausnahme. Naturgemäß ist das Interesse an den Auswirkungen der bereits eingetretenen sowie den noch zu erwartenden Bewegungen groß, sowohl bei Anwohnern wie auch den betroffenen Kommunen. In Epe helfen bei der Beantwortung dieser Fragestellungen die Erfahrungen aus 50 Jahren markscheiderischen Messungen an der Oberfläche (v.a. Nivellement, zunehmend auch GNSS/GPS und Radarinterferometrie) und im Untergrund (Hohlraumvermessungen der Kavernen). Neben den standortspezifischen Gegebenheiten wie Teufe und Salzgeologie ist bei Kavernen die Bedeutung der jeweiligen Nutzung entscheidend für das Senkungsgeschehen. Dabei liegt die größte Herausforderung in der mittel- bis langfristigen Antizipation des zukünftigen Kavernenbetriebs, da die Liberalisierung des Energiemarktes Mitte der 2000er Jahre zu einer sich mehr an betriebswirtschaftlichen Vorgaben orientierenden Fahrweise der Gasspeicher führte. Seitdem variiert die jährliche Konvergenz (Hohlraumverlust) der Gaskavernen stark, mit in der Folge ebenso veränderlichen Senkungsbeträgen an der Oberfläche. Die Annahme wahrscheinlicher Szenarien zum zukünftigen Betriebsgeschehen erlaubt trotz alledem verlässliche Senkungsprognosen, basierend auf dem etablierten analytischen Berechnungsmodell nach Sroka/Schober. Informationen zu verschiedenen Messmethoden (neben den markscheiderischen sind hier z.B. Beobachtungen des Grundwasserspiegels zu nennen), ihrer Ergebnisse und deren Bewertung sowie die Präsentation der Senkungsprognosen erfolgten in Epe bei mehreren Öffentlichkeitsterminen in den vergangenen Jahren. Essentiell war dabei der Rückgriff auf markscheiderisches Wissen, um die Informationen korrekt und verständlich zu transportieren. Bei mittlerweile fast 1 m Senkung im Kavernenfeld Epe und sich neu anbahnenden Nutzungskonzepten wie Wasserstoff- und Druckluftspeicherung ist eine erfolgreiche Kommunikation elementar, um ein gegenseitiges Vertrauen und Verständnis für unternehmerische Ziele einerseits sowie den Sorgen der Bevölkerung andererseits zu entwickeln. Im Folgenden soll das Senkungs- und Umweltmonitoring im Kavernenfeld Epe im Detail vorgestellt werden, ergänzt um die Erfahrungen in der Vermittlung dieser Ergebnisse.

台灣養殖漁業自1970年代起，進入快速成長時期，而在1980年代為台灣養殖漁業全盛時期，造就台灣成為「養蝦王國」、「養殖王國」揚名國際之美名，也為台灣沿海農漁村地區開拓新的漁業契機，而讓農漁民累積不少財富，故當時養殖漁業儼然成為台灣農業結構上重要之一環，對繁榮沿海農村經濟，安定農村社會，極具貢獻。 然而，諷刺的是，1980年代卻也是台灣耕地轉供養殖池之情況快速蔓延的時代，形成台灣沿海逐漸形成養殖區域性發展，卻也因為養殖漁業對於水土資源超限使用下，而超抽地下水而引起地層下陷及地下水體汙染等永世災難及耕地轉供養殖池諸多問題產生，導致環境不永續之後果，值得謀求解決之道。 本研究以質化研究中之個案研究法，以永續發展理念為基礎，運用文獻分析法及深度訪談法交互分析。先探討台灣養殖漁業管理及養殖漁業用地管理制度之演進及衍生出問題；再以宜蘭縣五結鄉季新村、錦眾村個案研究地區，深入探討台灣及宜蘭養殖漁業發展牽動五結鄉養殖區範圍擴散之可能原因及其影響，並就其耕地轉供養殖池之產業營運、違規使用、養殖環境轉變、養殖池棄養等不永續利用問題予以分析，最後提出「台灣養殖漁業與其用地管理制度改進策略」及「五結鄉養殖漁業與用地管理策略」。 經由研究發現，台灣超抽地下水及地層下陷問題最為嚴重之縣市，申請經營養殖漁業竟不需審核地下水之合法用水資格，而經個案地區研究也發現台灣及宜蘭養殖漁業發展牽動五結鄉耕地轉供養殖池之擴散，而經耕地轉供養殖池後，在養殖漁業沒落後，欲將棄養養殖池回復耕作環境困難重重，當地逐漸形成一片荒涼景象。 最後建議政府漁業單位應設計優良養殖環境之制度，即應先規劃養殖生產區並『主動』興建完成養殖專用之進水（海水、地下水）、排水之共同管線系統等相關養殖公共設施，並劃為非都市土地使用分區「養殖漁業生產區」（建議新增非都市土地使用分區），而該分區內之養殖池，有別於一般農地申請做養殖池，不應依據相同之法令規範，應放寬該養殖生產區內養殖池就地合法或是簡易申請程序以方便並快速取得合法養殖之資格，以有效管理養殖漁業減少違規使用情形發生及促進養殖漁業朝向永續發展方向邁進，並促進水土資源永續性利用。另建議政府漁業單位經全面性可行性評估後，認為不適合繼續養殖之地區應投入資源積極輔導該地區轉型，協助並引導該地區轉供較為永續利用之方向（如生態旅遊等）。 / Since 1970's the aquaculture develops rapidly in Taiwan, and becomes pre-vailing as the golden age of the aquaculture fishery in the 1980's. At that time Taiwan is well known of the kingdom of shrimp and aquaculture fishery in the world, and fishermen and farmers near the coast areas gain a new chance of incomes, so aquaculture fishery has become a very important chain of Taiwan's agriculture. It also has great contribution to flourishing village's economy and society stabilization. However, ironically, in 1980's many farms become aquaculture ponds quickly, that result in regional development of aquaculture fishery along the coast of Taiwan gradually, but overuse the resource of water and soil. Tapping groundwater inappropriately causes terrible disaster which lead to land subsi-dence and contamination of groundwater. The conversion of farms to aquacul-ture ponds cause many problems, that leads to environment being not sustaina-ble. There is an urgent need to find out relevant solutions. This research is based on two cases study the ideas of sustainable develop-ment.We adopt the modes of literature review and analysis, and depth interview. Firstly, we inquire into management system of the aquaculture industry and aq-uacultural land and the regarding problems. Secondly, we select the areas of Ji-sin village and Jin-jhong villege in Wujie Township Yilan County , in order to thoroughly inquire into possible reasons and influences that how aquaculture development in Yilan County and Wujie Township lead to the spreading of the areas for aquaculture production zone.Thirdly, we analyse problems of being not sustainable use of resources, such as the operation of the aquaculture pond, violating the rules of farmland use, changes of the cultivation environment, dis-card of aquaculture pond etc. Lastly, we put forth improvement strategies of aquaculture and its land management system both in Wujie Township and Tai-wan. Through the research, we find in counties with the most serious problems of tapping groundwater inappropriately and land subsidence in Taiwan, the gov-ernment doesn't need to examine the legality qualifications of the groundwater use when people apply for aquaculture fishery.We also find that aquaculture development in Yilan and Taiwan result in farmland conversion into aquaculture pond in the areas of Wujie Township . Because it is very difficult to make dis-carding aquaculture pond return to farmland, the region becomes a slice of desolate prospects gradually when the aquaculture decline. Finally, we suggest the Fishery Bureau of Government should design better institution for aquaculture environment. That is, they should plan for aquaculture production zone first and build public facilities of aquaculture fishery, such as the common pipeline system of using sea and groundwater for aquaculture fishery .The government should review the classification of non-urban land usage since the attributes of aquaculture ponds in "Aquaculture Production Zone" are different from others. In order to manage aquaculture fishery effec-tively, we also give some suggestions concerning decrease the occurrence of violating the rules, promoting the aquaculture fishery moving forward to sus-tainable development, and improving the sustainable use of water and soil re-source. We think to simplify application procedure of getting legal qualifications for aquaculture fishery may is not the best way but is an easy way to solve problems currently. Another suggestion is that after comprehensive feasibility evaluations, the Fishery Bureau of Government should actively invest adminis-tration resource to help areas that are not suitable for being use of aquaculture pond transferring to sustainable use, such as ecotourism etc.

Um modelo numérico tridimensional foi adaptado para o estudo da circulação gerada pelo vento sobre a plataforma continental da Região Sul do Brasil durante o verão e o outono. O modelo oceânico de Princeton (POM) é usado em um domínio limitado com grade curvilínea de alta-resolução, além de linha de costa e batimetria realísticas. As forçantes são variáveis no tempo e incluem tensão de cisalhamento do vento, descarga fluvial, campos termohalinos e nível médio do mar. Os objetivos são simular a resposta da plataforma a estas forçantes, comparar os resultados do modelo com observações oceanográficas afim de estabelecer a confiança do modelo, e subseqüentemente analisar os campos resultantes para ajudar na compreensão do comportamento da circulação observada. As variáveis do modelo mostram boa concordância geral com as correspondentes observações. É encontrado um claro padrão sazonal da circulação gerada pelo vento sobre a plataforma, com fluxos de superfície para sul e para o largo durante o verão, resultando em ressurgência de águas frias de fundo, e para norte e para a costa durante o outono, resultando em subsidência de águas menos densas. Tal circulação aumenta a estabilidade vertical no verão, devido ao aquecimento de superfície e ressurgência de águas frias, e aumenta a mistura vertical e a homogeneidade vertical no outono, devido à subsidência de águas menos densas, a qual causa forte aceleração da pluma fluvial existente na plataforma interna. Os resultados também demonstram que os cabos e promontórios da Região Sul do Brasil desempenham papel fundamental na variabilidade ao longo da costa do fluxo de ressurgência, incluindo o estabelecimento de jatos costeiros baroclínicos, os quais tendem a se separar da costa ao sul de cabos, mostrando uma circulação tridimensional de ressurgência, com complexa dependência espaço-temporal. Durante o outono, o empilhamento de subsidência, somado à presença da pluma fluvial, estabelece uma corrente costeira barotrópica, chamada aqui de \'\'Corrente Costeira de Rio Grande\'\', causando a intrusão de águas frias a partir do sul para a plataforma continental brasileira. A avaliação dos campos de velocidade mostra que o transporte de Ekman pleno se desenvolve na região ao largo das frentes de ressurgência ou subsidência, deixando em direção à costa uma zona dominada por fricção, com estratificação e velocidades perpendiculares fracas. Esta região é denominada aqui de \'\'plataforma interna\'\' e se estende da costa até a isóbata de 30m no verão e até a isóbata de 45m no outono, com esta variação resultando de variações na profundidade da camada de Ekman. / A three-dimensional numerical model has been adapted for the study of the wind-driven flow on the continental shelf off southern Brazil during the summer and autumn seasons. The Princeton Ocean Model (POM) is used in a limited area domain with a high-resolution (eddy resolving) curvilinear grid, with realistic coastline and bottom topography. The forcings include time-varying wind stress, termohaline fields, fluvial discharges and mean sea level. The objectives of the study are to simulate the response of the shelf circulation to these forcings, to compare model results with oceanographic observations, to stablish the model confidence, and to subsequently analyse the model fields a contribution to understand the behavior of the observed flow. The model variables show overall good agreement with corresponding observations. It is found a clear seasonal pattern of wind-driven circulation over the shelf, with surface offshore and southward net flow during summertime, which results in bottom cold water upwelling, and onshore and northward net flow during autumntime, which results in less dense water downwelling. This circulation enhances vertical stability in summer, due to solar surface heating and cold water bottom upwelling, and enhances vertical mixing and unstratified conditions in autumn due to downwelling of less dense water, which causes strong downwind acceleration of river plume innershelf waters. The results also demonstrate that coastal capes and promontories play a dominant role in causing alongshore variability of the upwelling flow over southern Brazil, including the setup of alongshore coastal baroclinic jets, which tend to separate from the coast south of capes, showing a three-dimensional upwelling circulation, with complex time and space dependence. During autumntime, the downwelling wind setup, in addition to the river plume waters, set up a barotropic coastal current, named here \'\'Rio Grande Coastal Current\'\', causing the intrusion of southern colder water over the Brazilian shelf. The evaluation of velocity fields shows that full Ekman transport develops in the region offshore of the upwelling or downwelling fronts, leaving onshore a region dominated by friction with relatively weak stratification and cross-shore currents. This region is named here \'\'innershelf\'\' and extends seaward from the coast until the 30m isobath in summer and the 45m isobath in autumn, showing this seasonal variation due to Ekman layer depth variations.

Um modelo numérico tridimensional foi adaptado para o estudo da circulação gerada pelo vento sobre a plataforma continental da Região Sul do Brasil durante o verão e o outono. O modelo oceânico de Princeton (POM) é usado em um domínio limitado com grade curvilínea de alta-resolução, além de linha de costa e batimetria realísticas. As forçantes são variáveis no tempo e incluem tensão de cisalhamento do vento, descarga fluvial, campos termohalinos e nível médio do mar. Os objetivos são simular a resposta da plataforma a estas forçantes, comparar os resultados do modelo com observações oceanográficas afim de estabelecer a confiança do modelo, e subseqüentemente analisar os campos resultantes para ajudar na compreensão do comportamento da circulação observada. As variáveis do modelo mostram boa concordância geral com as correspondentes observações. É encontrado um claro padrão sazonal da circulação gerada pelo vento sobre a plataforma, com fluxos de superfície para sul e para o largo durante o verão, resultando em ressurgência de águas frias de fundo, e para norte e para a costa durante o outono, resultando em subsidência de águas menos densas. Tal circulação aumenta a estabilidade vertical no verão, devido ao aquecimento de superfície e ressurgência de águas frias, e aumenta a mistura vertical e a homogeneidade vertical no outono, devido à subsidência de águas menos densas, a qual causa forte aceleração da pluma fluvial existente na plataforma interna. Os resultados também demonstram que os cabos e promontórios da Região Sul do Brasil desempenham papel fundamental na variabilidade ao longo da costa do fluxo de ressurgência, incluindo o estabelecimento de jatos costeiros baroclínicos, os quais tendem a se separar da costa ao sul de cabos, mostrando uma circulação tridimensional de ressurgência, com complexa dependência espaço-temporal. Durante o outono, o empilhamento de subsidência, somado à presença da pluma fluvial, estabelece uma corrente costeira barotrópica, chamada aqui de \'\'Corrente Costeira de Rio Grande\'\', causando a intrusão de águas frias a partir do sul para a plataforma continental brasileira. A avaliação dos campos de velocidade mostra que o transporte de Ekman pleno se desenvolve na região ao largo das frentes de ressurgência ou subsidência, deixando em direção à costa uma zona dominada por fricção, com estratificação e velocidades perpendiculares fracas. Esta região é denominada aqui de \'\'plataforma interna\'\' e se estende da costa até a isóbata de 30m no verão e até a isóbata de 45m no outono, com esta variação resultando de variações na profundidade da camada de Ekman. / A three-dimensional numerical model has been adapted for the study of the wind-driven flow on the continental shelf off southern Brazil during the summer and autumn seasons. The Princeton Ocean Model (POM) is used in a limited area domain with a high-resolution (eddy resolving) curvilinear grid, with realistic coastline and bottom topography. The forcings include time-varying wind stress, termohaline fields, fluvial discharges and mean sea level. The objectives of the study are to simulate the response of the shelf circulation to these forcings, to compare model results with oceanographic observations, to stablish the model confidence, and to subsequently analyse the model fields a contribution to understand the behavior of the observed flow. The model variables show overall good agreement with corresponding observations. It is found a clear seasonal pattern of wind-driven circulation over the shelf, with surface offshore and southward net flow during summertime, which results in bottom cold water upwelling, and onshore and northward net flow during autumntime, which results in less dense water downwelling. This circulation enhances vertical stability in summer, due to solar surface heating and cold water bottom upwelling, and enhances vertical mixing and unstratified conditions in autumn due to downwelling of less dense water, which causes strong downwind acceleration of river plume innershelf waters. The results also demonstrate that coastal capes and promontories play a dominant role in causing alongshore variability of the upwelling flow over southern Brazil, including the setup of alongshore coastal baroclinic jets, which tend to separate from the coast south of capes, showing a three-dimensional upwelling circulation, with complex time and space dependence. During autumntime, the downwelling wind setup, in addition to the river plume waters, set up a barotropic coastal current, named here \'\'Rio Grande Coastal Current\'\', causing the intrusion of southern colder water over the Brazilian shelf. The evaluation of velocity fields shows that full Ekman transport develops in the region offshore of the upwelling or downwelling fronts, leaving onshore a region dominated by friction with relatively weak stratification and cross-shore currents. This region is named here \'\'innershelf\'\' and extends seaward from the coast until the 30m isobath in summer and the 45m isobath in autumn, showing this seasonal variation due to Ekman layer depth variations.

臺灣西南沿海地區由於超抽地下水，地層下陷情形日益嚴重，究其原因乃地下水資源在國內仍處於「自由財」的狀態，用水兔費，使用自然缺乏效率，因而建立使用者付費制度，以確實維護地下水財產權，為當務之急。惟地下水資源具公共財的無排他性，在國內又無交易市場，其價值估算困難。是故，本文之主要目的，係應用非市場估價法中之「條件評價法」，以願付價格的形式估計地下水價值，並探求其影響因素，以做為制定政策之參考。 本文係以「準逐步競價法」為詢價結構設計，可同時獲得「單邊界樣本」、「雙邊界樣本」與「最終出價樣本」三種評價歷程，實證模型則分別以「Probit、Logit模型」、「存活模型」與「OLS模型」進行分析。 本文根據問卷調查的原始資料求出「每公頃土地」之地下水願付價格，最後則以台西地區為例，配合地下水的使用效益，計算出地下水供不同使用時之「使用價值」與「非使用價值」，而本研究對假設性問題的設計，使估計出來的地下水價值，亦可用以表示維護地下水資源對於防止地層下陷之效益。 實證結果顯示，「對水權費的認知與態度」以及「對地層下陷原因的認知」是影響支付意願的重要因素，故政府應加強宣導「使用者付費」理念，並教育用水者「超抽地下水是造成地層下陷的重要因素」，以利水權費制度的實施。

Le bassin intra-cordillérain du Callejon de Huaylas, situé au pied de la Cordillère Blanche (Nord-pérou), est fortement subsident au Pliocène. Il est remblayé par la formation continentale Lloclla, dont la partie supérieure témoigne de l'existence de glaciations pliocènes. Les déformations cassantes et ductiles sur les failles bordières, ainsi que les déformations synsédimentaires dans le bassin, montrent que la subsidence est contrôlée par une extension NE-SW, puis E-W. Les rejets verticaux pliocènes, sur les failles bordières, sont de l'ordre de 3500 m. La fin de la subsidence, au Quaternaire ancien, correspond à 2 épisodes successifs de raccourcissement, le premier E-W, le second N-S. Du Pléistocène à l'Actuel, une extension N-S s'exerce principalement sur le système de failles de la Cordillère Blanche, où se produisent des rejets normaux de 1000 m environ. Dans le cadre d'une évaluation des risques sismiques, les observations de terrains permettent de proposer une période de récurrence de l'ordre de 3000 ans, pour des séismes destructeurs (M=7), succeptibles de réactiver ce système de failles.

From the Proceedings of the 1972 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - May 5-6, 1972, Prescott, Arizona / Land is subsiding over a heavily mined aquifer in south central Arizona. Subsidence damages are inventoried to help provide a basis upon which cost studies can be performed to determine actions to lessen the economic impact of these damages. Water table drawdown produces increasing loading stress by three ways: changes in bouyant support of aquifer grains, changes in water table, or both. Two types of subsidence are recognized--one-directional compression, and near surface phenomenon. Damages due to natural structures, and to man-made structures are reviewed. Agricultural damages include field releveling, ditch repair and well damage. Damages to transportational facilities include highways, bridges, pipelines, and railroads. Damages to domestic and urban structures are suggested. Questionnaires, interviews and on-site inspections were used to collect information on land subsidence damages in the study area.

The goal of my work is to verify the effectiveness of various methods of collecting geodetic data in order to locate the decline of soil horizont in the dewatered areas.