Digital Geologic Map Research Articles

Site suitability analysis for potential agricultural land with spatial fuzzy multi-criteria decision analysis in regional scale under semi-arid terrestrial ecosystem

The main purpose of this study is to identify suitable potential areas for agricultural activities in the semi-arid terrestrial ecosystem in the Central Anatolia Region. MCDA was performed in fuzzy environment integrated with GIS techniques and different geostatistical interpolation models, which was chosen as the basis for the present study. A total of nine criteria were used, as four terrain properties and five soil features to identify potential sites suitable for agriculture lands in Central Anatolia which covers approximately 195,012.7 km2. In order to assign weighting value for each criterion, FAHP approach was used to make sufficiently sensitive levels of importance of the criteria. DEM with 10 m pixel resolution used to determine the height and slope characteristics, digital geology and soil maps, CORINE land use/land cover, long-term meteorological data, and 4517 soil samples taken from the study area were used. It was identified that approximately 30.7% of the total area (59,921.8 ha) is very suitable and suitable for potential agriculture activities on S1 and S2 levels, 42.7% of the area is not suitable for agricultural uses, and only 27% of the area is marginally suitable for agricultural activities. Besides, it was identified that 34.8% of the area is slightly suitable.

Combining implicit geological modeling, field surveys, and hydrogeological modeling to describe groundwater flow in a karst aquifer

In three-dimensional (3-D) implicit geological modeling, the bounding surfaces between geological units are automatically constructed from lithological contact data (position and orientation) and the location and orientation of potential faults. This approach was applied to conceptualize a karst aquifer in the Middle Triassic Muschelkalk Formation in southwest Germany, using digital elevation data, geological maps, borehole logs, and geological interpretation. Dip and strike measurements as well as soil-gas surveys of mantel-borne CO2 were conducted to verify the existence of an unmapped fault. Implicit geological modeling allowed the straightforward assessment of the geological framework and rapid updates with incoming data. Simultaneous 3-D visualizations of the sedimentary units, tectonic features, hydraulic heads, and tracer tests provided insights into the karst-system hydraulics and helped guide the formulation of the conceptual hydrogeological model. The 3-D geological model was automatically translated into a numerical single-continuum steady-state groundwater model that was calibrated to match measured hydraulic heads, spring discharge rates, and flow directions observed in tracer tests. This was possible only by introducing discrete karst conduits, which were implemented as high-conductivity features in the numerical model. The numerical groundwater flow model was applied to initially assess the risk from limestone quarrying to local water supply wells with the help of particle tracking.

Geomorphological Analysis Applied to the Evolution of the Quaternary Landscape of the Tormes River (Salamanca, Spain)

This paper presents a geomorphological analysis of the Tormes River during the Quaternary. The Tormes River formed in the center-west of the Iberian Peninsula in the province of Salamanca. It runs along a Cenozoic basin with basement materials and through Varisco, and consists of mainly granitic and metamorphic materials, leaving a wide stream of river terraces, both erosional and depositional, that confirm its evolution throughout the Quaternary. Geomorphological analyses using Geographic Information Systems tools, Digital terrain model high resolution (MDT05, LIDAR), Orthophotos (scale 1:5000), and geological maps (1:50,000 Series Magna) have allowed different morphologies and depositional terraces to be distinguished, namely, 19 levels of erosional terraces and 3 levels of erosion surfaces. Based on these correlations, the levels of terraces in the Tormes River between T1 (+140 m) and T7 (+75–80 m) are located in the Pleistocene, those between T8 (+58–64 m) and T14 (+18–23 m) in the Middle Pleistocene, those between T15 (+12–13 m) and T17 (+6–7 m) in the Upper Pleistocene, and those between T18 (+3 m) and T19 (+1.5 m) in the Holocene. The erosion surfaces are divided into six levels: S6 (+145 m), S5 (+150 m), S4 (+160 m), S3 (+170 m), S2 (+180 m) and S1 (+190 m) located in the Lower Pleistocene, This work performs a geomorphological mapping procedure applied to the evolutionary analysis of the landscape, so that it determines different geomorphological units allowing the relief and morphology of the terrain in past times, establishing a dynamic analysis of the landscapes.

The 3D modelling techniques of digital geological mapping

Digital geological mapping has been widely applied in regional geological surveying in China since 2004. Using geological mapping data obtained by the digital geological mapping technique to build 3D geological modelling is the trend of the future. Based on previous research, a new method of constructing 3D geological models of shallow surfaces by using digital geological mapping routes and topographic data is proposed in this paper. The key steps of this modelling method are described systematically in the paper. These steps include data pre-processing, construction of an original database, construction of geological boundaries, and model combination. In particular, we introduce in detail the model construction methodologies of the model boundary surface, digital elevation model (DEM) surface, Quaternary interface, fault plane, overlying residual stratum interface, layered geological interface, rock mass interface, and others. During the geological interface construction, we should follow two principles: (1) use the boundary and occurrence data as the main modelling data, and use the high-precision subsurface interface data as constraint data; (2) construct younger geological bodies first, and then construct older geological bodies. The next step is to compose sectionalised geological interfaces and use them to generate a geological interface of wider range. The interface construction progresses from small to large and is constantly constrained and continuously improved. Based on this new modelling method, we successfully constructed two 3D geological models, the 1:25,000 Xiaosuangou and the 1:50,000 Tuoshang models, and achieved good results. This modelling method has the advantages of simple realisation, high speed, high accuracy, and good applicability. Using this method to build 3D geological models can facilitate further development and utilisation of existing digital geological mapping data. The 3D geological models can be used as a new way of expressing the regional geological survey results, as well as the constraint data of deep 3D geological modelling in the future.

Selected cartographic products of the Polish Geological Survey in light of the international data standards and OneGeology experience

Selected cartographic products of the Polish Geological Survey in light of the international data standards and OneGeology experience

Anatomy of a late Quaternary carbonate island: Constraints on timing and magnitude of sea-level fluctuations, West Caicos, Turks and Caicos Islands, BWI

The data set of the island of West Caicos consists of a combination of high-resolution lidar and digital imagery, radiometric data, and amino acid racemization (AAR) D/L values as well as extraordinary preservation of sedimentary and bio-constructed deposits on the island. Together with a well-established regional stratigraphic framework from the neighboring Bahamian island chain and detailed field mapping, the West Caicos data set provides an opportunity to advance our understanding of the link between carbonate stratigraphy and the controlling parameters of sea level, sediment supply, tectonics, and climate. The exceptionally well-preserved stratigraphic record of the mid–late Pleistocene from West Caicos allows recognition of marine isotope stages (MIS) 9/11, 5e, and Holocene. The west coast of the island provides a continuous 8.4 km exposure of the MIS 5e record that enhances our understanding of the intra-MIS 5e bipartite succession in this region and supports a sea-level lowering that occurred during the last interglacial (LIG).West Caicos accreted as a series of eolian, foreshore–shoreface, barrier-reef, and fringing-reef facies. Shoreline positions for all but the MIS 7 and MIS 5a/c deposits are now captured in the sub-meter geodetic-quality topobathy lidar survey. The Star Town unit of MIS 9/11 age forms the southern margin of the island as well as the central karst-modified spine, with uranium–thorium (UTh) coral ages of between 368 and 365 thousand years ago (ka) and a D/L Glu average of >0.60. Early MIS 5e strata include the Railroad Ridge unit in the center of the island, which was previously identified as one of the older units. The Railroad Ridge unit is a north–south linear dune ridge that has a D/L Glu average of 0.52 and indicates the onset of sediment sources from the east associated with a flooded central Caicos Platform. Approximately synchronously, the early MIS 5e South Reef unit (+3.75–4 m sea-level elevation) nucleated on the western coast of West Caicos, attached to the middle Pleistocene Star Town unit. The South Reef corals yield an average coral UTh age of 126.5 ka, with an average D/L Glu from skeletal matrix of 0.46. This transitional barrier/fringing reef is unconformably overlain by the late MIS 5e Boat Cove unit. Corals in the basal transgressive phase of this upper MIS 5e Boat Cove unit yield an average 120.6 ka UTh and average D/L Glu of 0.45. Shallow-marine, foreshore, and eolian facies of the late MIS 5e rest on a wave-cut terrace that cuts the early MIS 5e South Reef unit by as much as 3 m down to a +0.5 m above present sea-level elevation. The upper MIS 5e Boat Cove unit displays a maximum of +4.5 m elevation above present-day sea level, measured from the middle of the foreshore. This estimate may be a minimum value as the exposures on the west coast are part of a forced regressive foreshore sequence. Last stages of the upper MIS 5e deposition are seen in a series of regressive dune-beach ridge deposits referred to as the Northeast Ridges unit, with sea-level positions ranging from +4.5 m early in the central part of West Caicos, to +0.5 m on the far northeast coast, eventually building down below present-day sea level. This sea-level history fits well with previously documented records in the Bahamas and globally, and the extensive erosion supports a short-lived (between 126 and 120 ka) intra-MIS 5e relative-sea-level fall. Holocene deposition on West Caicos is restricted to northern and eastern margins of the island as a combination of strandplain and dune ridge mixed skeletal–oolitic units.Using the high-resolution digital elevation model (DEM) and linked digital geologic map makes it possible to compare areas of the different Pleistocene and Holocene units quantitatively and to constrain volumetric assessments and accumulation rates on the island for different units. The peak sediment volume production/accumulation rate—between 6.5 and 8 × 106 m3 or between 2.2 and 2.7 × 106 m3 per ka—is observed in the upper MIS 5e unit. This rate is 5 times greater than the 0.5 × 106 m3 per ka estimated for the Holocene ooid dune-ridge/strandplain complex, suggesting that the combination of higher sea level, greater wave and wind energy, and warmer ocean temperatures may have fostered the higher rate of chemically precipitated sediment supply.

A seamless database for a digital geological map of central Italy: the case of Emilia-Romagna, Marche, Tuscany and Umbria regions

In 2012, the Emilia-Romagna, Marche, Tuscany and Umbria regions signed a Memorandum of Understanding for the development of a geological map of their territories. Based on previous results, a unique geological database has been produced with a geographic mapping in GIS vector format at a scale of 1:10,000. The emergence of inconsistencies in initial cartography made necessary the revision of four pilot areas: “Conca-Marecchia”, “Tuscany-Umbria”, “Pistoia-Modena” and “Massa Carrara-Parma”. With regards to the latter, the problems to be solved were: a) the position and correlation between tertiary turbid arenaic formations; b) interpretation of the position of marvelous sequences; c) interpretation of the tectonic structures of the Passo del Cerreto- F.Secchia, with outgrowth of medium-grade metamorphic rocks tectonically juxtaposed to evaporitic triassic formations; d) the nature and age of the tectonic contacts at the roof of the succession of the Passo del Cerreto-F.Secchia and of the area of the M.Ventasso. To solve some critical issues, field data have been integrated with information about the age of the stratigraphic successions mentioned above, through biostratigraphic and petrographic studies. The final product consisted in a new database useful to test the geological data concerning some critical revision areas.

Digital geologic map and geochronologic, geochemical and geothermal database of the south-eastern part of the Sierra Madre Occidental, Mexico


 
 
 We present a first interactive digital geological map of the southeastern part of the Sierra Madre Occidental at its borders with the Mesa Central. The area of the geological cartography covers approximately 120,000 km2 that includes part of the states of Jalisco, Zacatecas, Aguascalientes and Durango. The geology has been compiled in ArcGIS through an interpretation of all the information available in the literature, integrated with our own geological mapping. Published maps were georeferenced and, as far as possible, the traces of the geologic limits and structures with a clear morphological expression were refined using digital elevation models and satellite images available in Google Earth. The map includes 15 geological units and the main tectonic structures. The informal geological units used in the map are chronostratigraphic and lithological and are designed to highlight the main magmatic episodes that shaped the region. The age assignment for each unit has been compared with a geochronological database that includes 304 ages. The lithological classification of each polygon has been compared for consistency with a geochemical database compiled from the literature that includes 313 samples. We also added a layer of information with the main hot springs of the region and their temperature. 
 
 

Digital Geologic Cartography and Geochronologic Database of the Trans-Mexican Volcanic Belt and Adjoining Areas

We present the first interactive digital geologic map of the Trans-Mexican Volcanic Belt (TMVB). The area covered by the cartography span 10° of Longitude (106°- 96° W) and 2°45’ of Latitude (19°-21°45’ N). The geology has been compiled in ArcGIS through an interpretation of all the information available in the literature and integrated with our own geologic mapping. Published maps were digitized from printed copies; when possible, the location of features with clear morphological expression was corrected using digital elevation models within the GIS. The map includes 36 geologic units, faults, volcanic vents, and calderas. The informal geologic units used in the compilation are chronostratigraphic and lithologic and were designed to emphasize the main volcanic episodes that make up this volcanic province. The age assignment for each unit has been cross-checked with a geochronologic database that includes 2009 ages, which can be displayed on the map with access to their attributes. Lithology of each polygon has been also checked against a large geochemical database compiled from the literature.

Analysis ofSpectralReflectivityof Pila SpiFormation in Bashiqa, Maklob and Ean Alsafra Structures/Northern Iraq

The results of theanalysis ofspectral reflecting curves of,selected(17)rocksand (4) soil samples of Pila Spiformation in both Ba'shiqahandMaklobstructures northern Iraq, to Clear contrast in reflectivity.This discrepany is due to the obvious difference in the physical and chemical characteristics of carbonate and dolomatic roks of this formation. A variety of image processing techniques were applied on land sat ETM+7 image of the study area depending on spectral reflecting results of the above samples. Numerous false colored combination were carried out on(1, 2, 3, 4, 5, 7)image bands. Several image ratio were applied and integrated with(RGB) system to get the best results digital geological map was produced by the use of resulted images which were compared their results with maps and field information of the area.

Digital soil map of the Ussuri River basin

On the basis of digital soil, topographic, and geological maps; raster topography model; forestry materials; and literature data, the digital soil map of the Ussuri River basin (24400 km2) was created on a scale of 1: 100000. To digitize the initial paper-based maps and analyze the results, an ESRI ArcGIS Desktop (ArcEditor) v.10.1 (http://www.esri.com) and an open-code SAGA GIS v.2.3 (System for Automated Geoscientific Analyses, http://www.saga-gis.org) were used. The spatial distribution of soil areas on the obtained digital soil map is in agreement with modern cartographic data and the SRTM digital elevation model (SRTM DEM). The regional soil classification developed by G.I. Ivanov was used in the legend to the soil map. The names of soil units were also correlated with the names suggested in the modern Russian soil classification system. The major soil units on the map are at the soil subtypes that reflect the entire vertical spectrum of soils in the south of the Far East of Russia (Primorye region). These are mountainous tundra soils, podzolic soils, brown taiga soils, mountainous brown forest soils, bleached brown soils, meadow-brown soils, meadow gley soils, and floodplain soils). With the help of the spatial analysis function of GIS, the comparison of the particular characteristics of the soil cover with numerical characteristics of the topography, geological composition of catchments, and vegetation cover was performed.

Cellular automata approach for modelling climate change impact on water resources

ABSTRACTIn this work, we consider the cellular automata (CA) approach for modelling the climate change impact on water resources. This consists in: constructing a CA model that describes the water cycle dynamics taking into account physical terrain attributes and climatic constraints; coupling the CA model with climate projection scenarios for a considered region as input data; determining and analysing in output the variations of the underground, surface and evaporated water. We present these variations per time interval and per zone of influence. As an application, we consider simulation for a basin in northern Morocco using a simulation software we have designed in Java Object Oriented Programming.We consider cellular automata (CA) approach for modelling climate change impact on water resources. This consists in, first constructing a CA model that describes the water cycle dynamics taking into account physical terrain attributes and climatic constraints, then coupling the CA model with climate projection scenarios for a considered region as input data, and we determine and analyze in output the variations of the water resources (groundwater and surface water). We present these variations per time interval and per zone of influence. The approach application is for a basin in northern Morocco for which we use simulation software that we have designed in Java Object Oriented Programming. Digital terrain model, geological map and satellites image are used for input data.

3D geological modeling and visualization of the subsurface data of the Piemonte plains derived from the Geodatabase of digital Geological map of Piemonte

Three-dimensional (3D) subsurface modelling and visualization of seven regional unconformity-bounded stratigraphic units, (synthems) of the Messinian-Quaternary succession of the Po Plain Basin and Savigliano-Alessandria Basin are here described. 3D model is developed using the EnterVol Ctech® software environment, grounding on information stored in GeoPiemonte Map database. This modelling allows to visualise the geological data and to establish topological relationships between the analysed objects, coupling the data processing capabilities of GIS with 3D modeling and sharing the result on 3D WebGIS service of ARPA Piemonte Geoportal.

Book Reviews

Mineral Resources in the Arctic. Rognvald Boyd, Terje Bjerkgard, Bobo Nordahl, Henrik Schiellerup, Editors. Pp. 484. 2016. Geological Survey of Norway Special Publication. ISBN 978-82-7385-160-4. NOK 600. (Also free download at https://www.ngu.no/en/publikasjon/mineral-resources-arctic). Mineral Resources in the Arctic reviews the geologic framework, mining history, and mineral resources of the arctic. The volume is an outgrowth of a study originally undertaken by the Russian Ministry of Natural Resources that sought, in 2003, to form an international cooperative effort to produce digital geologic and geophysical maps of the arctic region. Two years later, a consortium of national government agencies from Canada, Denmark, Finland, Norway, Russia, Sweden, and the United States signed a cooperative agreement, entitled “Circum-Arctic Mineral Resources Project.” This book is among the products of the project; others include a geological map, a magnetic and gravity map, and a tectonic map of the arctic. Several criteria can define the arctic, including the Arctic Circle, at 66°33′46″ north, a 10°C summer isotherm, and the northernmost tree line. The authors chose the southern boundary of the arctic as the 60th parallel, which includes an area of about 40 million square kilometers, including submerged lands. An exception was made for Alaska, where data from the “Southeastern Panhandle” was included to about the 55° latitude. Of the many stated reasons for the effort, one seems obvious. With receding ice conditions, the Northwest Passage, Northeast Passage, and the Northern Sea routes provide accessibility to regions previously deemed too remote for mineral resource development. Hence this new environmental reality, coupled with the high potential to find new resources, provide a compelling reason for the volume’s release. Chapters on the geologic frameworks of Alaska, Canada, Greenland, Iceland, the seafloor north of Iceland, Norway, Sweden, Finland, and Russia were written by 59 authors, citing more than 1,100 references in this 482-page volume. All chapters contain excellent photos and graphics to illustrate important districts and deposits. Multiple hypotheses that debate the origins of important mineral deposits are presented. Goldfarb et al. wrote the …

The State Geologic Map Compilation (SGMC) Geodatabase of the Conterminous United States

The State Geologic Map Compilation (SGMC) geodatabase of the conterminous United States (https://doi.org/10.5066/F7WH2N65) represents a seamless, spatial database of 48 State geologic maps that range from 1:50,000 to 1:1,000,000 scale. A national digital geologic map database is essential in interpreting other datasets that support numerous types of national-scale studies and assessments, such as those that provide geochemistry, remote sensing, or geophysical data. The SGMC is a compilation of the individual U.S. Geological Survey releases of the Preliminary Integrated Geologic Map Databases for the United States. The SGMC geodatabase also contains updated data for seven States and seven entirely new State geologic maps that have been added since the preliminary databases were published. Numerous errors have been corrected and enhancements added to the preliminary datasets using thorough quality assurance/quality control procedures. The SGMC is not a truly integrated geologic map database because geologic units have not been reconciled across State boundaries. However, the geologic data contained in each State geologic map have been standardized to allow spatial analyses of lithology, age, and stratigraphy at a national scale. A full discussion of the procedures and methodology used to create this dataset is available in the accompanying report: Horton, J.D., San Juan, C.A., and Stoeser, D.B, 2017, The State Geologic Map Compilation (SGMC) geodatabase of the conterminous United States (ver. 1.1, August 2017): U.S. Geological Survey Data Series 1052, 46 p., https://doi.org/10.3133/ds1052.

Evaluation of land cover changes and Black locust occurrence in agricultural landscape. Case study: Podolie and Častkovce cadastral areas, Slovakia

This study presents spatial analysis of agricultural landscape changes in the Podolie and Castkovce cadastral areas since 1949. Data for analysis was obtained from historical aerial photographs (from 1949, 1986 and 2006), detailed field mapping and Black locust ( Robinia pseudoacacia L.) monitoring. Land cover changes were assessed from the aerial photographs based on the CORINE land cover legend, environmental variables were derived from digital elevation model (DEM) and detailed geological and soil maps. Data was spatially compared and assessed by regression analysis for interpretation of Black locust occurrence. The most significant land cover changes occurred between 1949 and 1986 when agricultural areas were replaced by forest and semi-natural areas. One of the aspects of landscape changes is abandonment of agricultural landscape and occupancy this new transformed surfaces by invasive plant taxons (e. i. Robinia pseudoacacia L.). Black locust occurrence was mainly influenced by landscape management changes and subsequent land cover changes (afforestation from 1949 to 1986), especially in regions of dispersed settlements (Podolske and Korytnianske kopanice) after agricultural collectivisation. Environmental variables had little effect on Black locust expansion in these areas.

수치지질도의 세계측지계 좌표변환 (ArcToolbox를 이용한 충주 및 황강리 도폭의 사례)

우리나라에서는 2010년부터 국제적으로 통용되는 세계측지계의 사용을 의무화하였다. 이에 따라 현재 국토지리정보원에서 발행되는 수치지도는 세계측지계 기준으로 제공되고 있다. 그러나 현재도 대부분의 수치지질도는 동경측지계 기준으로 제공되고 있다. 따라서 사용자들은 수치지질도를 이용한 2D/3D 지질공간분석에 있어서 수치지질도의 좌표를 세계측지계로 변환하여 사용할 수밖에 없는 실정이다. 따라서 본 논문에서는 수치지질도의 좌표정의 및 변환에 익숙하지 않은 사용자들을 위해 ArcToolbox를 이용한 동경측지계로의 좌표정의 및 세계측지계로의 좌표변환 방법을 소개하고자 한다. 이때 좌표정의 및 변환의 객관성을 도모하기 위해서 인접한 1:5만 축척의 충주와 황강리의 지질도폭을 예를 들어 사용하였다. 동경측지계 좌표정의에 있어 충주와 황강리 도폭을 각각 동경측지계 중부원점과 동부원점으로 정의하였고, 황강리 도폭을 다시 동경측지계 중부원점으로 변환하여 충주 도폭과 병합하였다. 세계측지계 좌표변환에 있어 병합된 충주 및 황강리 도폭은 다시 세계측지계 중부원점으로 변환하였다. 변환 결과, 병합된 충주와 황강리 도폭은 수치지도(대소 367041) 위치와 정확히 일치하였다. 이와 같은 방법으로 과거에 만들어진 수치지질도의 좌표문제를 효과적으로 해결 할 수 있었다. 따라서 본 논문에서 제시한 좌표정의 및 변환 방법은 향후 다양한 수치주제도들의 2D/3D 지질공간분석시 주제도들의 전처리 과정으로 유용하게 사용될 수 있을 것으로 기대된다. In Korea, the use of world geodetic system(WGS) has been mandated in year 2010. Accordingly, the national geographic information institute(NGIS) provides the digital maps according to the WGS. Nevertheless, most of the digital geological maps are still based on the Tokyo Datum(TD). Therefore, users should conduct 2D/3D geological spatial analysis after converting the coordinates of digital geological maps to WGS. The conversion process is often tedious and troublesome for certain users. Therefore, in this study, the method to transform coordinate from TD to WGS using ArcToolbox is introduced for users not familiar with the process. For a better appreciation, the Chungju and Hwanggang-ri digital sheets of 1:50,000 scale was chosen as an example. Here, Chungju and Hwanggang-ri sheets were defined based on the TD-central origin and TD-east origin, respectively. The two sheets were merged after the transformation of TD-east origin of Hwanggang-ri to the TD-central origin, and eventually transformed to WGS-central origin. The merged map was found to match exactly with the digital map(Daeso 367041). The problem of coordinate determination in previous digital geological maps was solved effectively. The proposed method is believed to be helpful to 2D/3D geological spatial analysis of various geological thematic maps.

Modelling macroseismic observations for historical earthquakes: the cases of the M = 7.0, 1954 Sofades and M = 6.8, 1957 Velestino events (central Greece)

We attempt to model the spatial distribution of the strong ground motion for the large M = 7.0, 1954 Sofades and M = 6.8, 1957 Velestino events (southern Thessaly basin, central Greece), using the macroseismic intensities (I M M up to 9+) observed within the broader Thessaly area. For this reason, we employ a modified stochastic method realised by the EXSIM algorithm for extended sources, in order to reproduce the damage distribution of these earthquakes, in an attempt to combine existing earthquake information and appropriate scaling relations with surface geology and to investigate the efficiency of the available macroseismic data. For site-effects assessment, we use a new digital geological map of the broader Thessaly basin, where geological formations are grouped by age and mapped on appropriate NEHRP soil classes. Using the previous approach, we estimate synthetic time series for different rupture scenarios and employ various calibrating relations between PGA/PGV and macroseismic intensity, allowing the generation of synthetic (stochastic) isoseismals. Also, different site amplification factors proposed for the broader Aegean area, according to local geology, are tested. Finally, we also perform a sensitivity analysis of the fault location, taking into account the available neotectonic data for the broader southern Thessaly fault zone. The finally determined fault locations are different than previously proposed, in agreement with the available neotectonic information. The observed macroseismic intensities are in good agreement with the ones derived from the synthetic waveforms, verifying both the usefulness of the approach, as well as of the macroseismic data used. Finally, site-effects show clear correlation with the geological classification employed, with constant amplification factors for each soil class generally providing better results than generic transfer functions.

Geodatabase strategy for a digital Geological map of the central-eastern Nepal Himalaya

In this preliminary note, we describe our strategy for collecting, storing and representing new and old geological data acquired in several sectors of the central-eastern Himalaya where, since the 70's, researchers of the CNR- IGG Torino and the Department of Earth Sciences of the University of Torino addressed a significant part of their activity. All the geologic features (including rock samples, petrographic, petrologic and structural observations and measurements) are stored and harmonized in a suitable geodatabase using ArcGIS. Standard criteria are used to describe their typology and quality, facilitating future homogeneous data implementation and a correct data traceability. This geodatabase represents the fundamental starting point for the editing of a digital geological map of the central-eastern Nepal Himalaya.

Radon potential, geologic formations, and lung cancer risk

ObjectiveExposure to radon is associated with approximately 10% of U.S. lung cancer cases. Geologic rock units have varying concentrations of uranium, producing fluctuating amounts of radon. This exploratory study examined the spatial and statistical associations between radon values and geological formations to illustrate potential population-level lung cancer risk from radon exposure. MethodThis was a secondary data analysis of observed radon values collected in 1987 from homes (N=309) in Kentucky and geologic rock formation data from the Kentucky Geological Survey. Radon value locations were plotted on digital geologic maps using ArcGIS and linked to specific geologic map units. Each map unit represented a package of different types of rock (e.g., limestone and/or shale). Log-transformed radon values and geologic formation categories were compared using one-way analysis of variance. ResultsObserved radon levels varied significantly by geologic formation category. Of the 14 geologic formation categories in north central Kentucky, four were associated with median radon levels, ranging from 8.10 to 2.75pCi/L. ConclusionRadon potential maps that account for geologic factors and observed radon values may be superior to using observed radon values only. Knowing radon-prone areas could help target population-based lung cancer prevention interventions given the inequities that exist related to radon.