East-west Orientation Research Articles

Environment and morphology of mesoscale convective systems associated with the Changma front during 9–10 July 2007

Abstract. To understand the different environment and morphology for heavy rainfall during 9–10 July 2007, over the Korean Peninsula, mesoscale convective systems (MCSs) that accompanied the Changma front in two different regions were investigated. The sub-synoptic conditions were analysed using mesoscale analysis data (MANAL), reanalysis data, weather charts and Multi-functional Transport Satellite (MTSAT-IR) data. Dual-Doppler radar observations were used to analyse the wind fields within the precipitation systems. During both the case periods, the surface low-pressure field intensified and moved northeastward along the Changma front. A low-level warm front gradually formed with an east-west orientation, and the cold front near the low pressure was aligned from northeast to southwest. The northern convective systems (meso-α-scale) were embedded within an area of stratiform cloud north of the warm front. The development of low-level pressure resulted in horizontal and vertical wind shear due to cyclonic circulation. The wind direction was apparently different across the warm front. In addition, the southeasterly flow (below 4 km) played an important role in generating new convective cells behind the prevailing convective cell. Each isolated southern convective cell (meso-β-scale) moved along the line ahead of the cold front within the prefrontal warm sector. These convective cells developed when a strong southwesterly low-level jet (LLJ) intensified and moisture was deeply advected into the sloping frontal zone. A high equivalent potential temperature region transported warm moist air in a strong southwesterly flow, where the convectively unstable air led to updraft and downdraft with a strong reflectivity core.

Assessment of Landscape Characteristics and Changes in the Khangchendzonga National Park, Sikkim Himalaya, India

The Khangchendzonga National Park (KNP) in India forms a part of the eastern Himalaya global biodiversity hotspot. Being the third highest protected area in the world, much of the park is inaccessible and has remained least understood. In this study, Remote Sensing and GIS tools were used to quantify landscape composition, configuration and patterns of changes in vegetation cover. From Landsat ETM+ data, 10 land cover types could be classified with 81% accuracy, which showed relatively higher coverage of snow, rock and alpine meadows. FRAGSTATS recognized 70790 patches with mean patch size of 1.2 ha. Watershed based approach showed that parts of KNP that had higher landscape heterogeneity, reflected a greater Himalayan character, high elevation gradient, east west orientation and not dominantly sculptured by valley glaciers. Riverine areas were found to be susceptible to glacial lake outburst and flash floods. Also vegetation cover has substantially declined at lower elevations (1000 to 2500 m) in the last three decades, particularly in portions not shielded from the villages by buffer forests. The park management needs to evolve innovative co-management models, use the riverine zone carefully, strengthen buffer zone management and prioritize conservation measures in the high impact areas.

Phylogeography of co-distributed dune scorpions identifies the Amu Darya River as a long-standing component of Central Asian biogeography

Although only distantly related, Anomalobuthus and Liobuthus are monotypic and sympatric scorpion genera with psammophilic phenotypes well-suited to the dune communities of the Karakum and Kyzylkum deserts of Central Asia. We predicted that this unique combination of phenotypic convergence and sympatry should have resulted in shared phylogeographic histories. We tested this hypothesis by using mitochondrial DNA data and molecular dating techniques to reconstruct the matrilineal genealogies of A. rickmersi and L. kessleri. We also developed current and late-glacial species distribution models and landscape interpolations of genetic distances to assess the influence of historical barriers and Pleistocene climates on the phylogeography of each species. Both genera exhibited signals of restricted gene flow across the Amu Darya River, supporting our prediction of mutual histories. Levels of initial genetic differentiation within each genus date to the Late Miocene to late Pliocene. Distribution models indicate that suitable habitat may have fragmented during the Pleistocene, generally in an east-west orientation. Although the observed genetic differentiation at the Amu Darya River could be a coincidental product of lineage sorting, the fact that both species display this pattern suggests that the river has been an important biogeographic element in the development of Central Asian biotas.

Calculation of total solar fraction for different orientation of greenhouse using 3D-shadow analysis in Auto-CAD

The distribution of the incoming transmitted solar radiation (radiation which enters inside the greenhouse through canopy cover) on the floor and on the inner walls of the greenhouse has been studied to evaluated total solar fraction/solar fraction. Total solar fraction/solar fraction is required to write an energy balance equation for each component of a greenhouse. The evaluation has been done for different orientations of an even span greenhouse located at New Delhi (28.5° latitude), India. The effect of length and the width of the greenhouse on the total solar fraction have also been evaluated. Three-dimensional shadow analysis in Auto-CAD has been used for the study. A typical clear day of winter and summer has been considered and it was observed that total solar fraction was higher in winter as compared to summer. Numerically, there is not much effect of orientation on total solar fraction of a day for a greenhouse. However, an orientation of 45° clock-wise (for greenhouse initially at East–West orientation) resulted in lowest radiation loss during winter and maximum loss during summer. Total solar fraction plays an important role for smaller greenhouses. The methodology can be used for designing a greenhouse of any shape and size for any location.

What does early Christianity look like? Mortuary archaeology and conversion in Late Iron Age Scotland

The study of the inhumation cemeteries of Late Iron Age Scotland tends to revolve around the vexed question of whether or not they provide evidence for Christianity. As a result, our approach has been to look for ‘Christian’ practices (lack of grave goods, west-east orientation) that are expectations based on analogy with the more standardised Christianity of the later medieval period. As these burial practices originate in a Late Iron Age context, recent theoretical approaches from the study of late prehistory also need to be applied. It is the emergence of cemeteries that is new in the mid-first millennium AD, and this distinction is still under-theorised. Recent theoretical models seek to understand the significance of place, and how these cemeteries are actively involved in creating that place rather than using a predefined ‘sacred’ place. By tracing their role in shaping and being shaped by their landscapes, before, during and after their use for burial, we can begin to speak more clearly about how we can use mortuary archaeology to study the changes of c. AD 400–600. It is argued that the ambiguity of these sites lies not with the burials themselves, but in our expectations of Christianity and paganism in the Late Iron Age.

A test of the influence of continental axes of orientation on patterns of human gene flow.

The geographic distribution of genetic variation reflects trends in past population migrations and can be used to make inferences about these migrations. It has been proposed that the east-west orientation of the Eurasian landmass facilitated the rapid spread of ancient technological innovations across Eurasia, while the north-south orientation of the Americas led to a slower diffusion of technology there. If the diffusion of technology was accompanied by gene flow, then this hypothesis predicts that genetic differentiation in the Americas along lines of longitude will be greater than that in Eurasia along lines of latitude. We use 678 microsatellite loci from 68 indigenous populations in Eurasia and the Americas to investigate the spatial axes that underlie population-genetic variation. We find that genetic differentiation increases more rapidly along lines of longitude in the Americas than along lines of latitude in Eurasia. Distance along lines of latitude explains a sizeable portion of genetic distance in Eurasia, whereas distance along lines of longitude does not explain a large proportion of Eurasian genetic variation. Genetic differentiation in the Americas occurs along both latitudinal and longitudinal axes and has a greater magnitude than corresponding differentiation in Eurasia, even when adjusting for the lower level of genetic variation in the American populations. These results support the view that continental orientation has influenced migration patterns and has played an important role in determining both the structure of human genetic variation and the distribution and spread of cultural traits.

Crustal deformation map for the 2011 off the Pacific coast of Tohoku Earthquake, detected by InSAR analysis combined with GEONET data

Applying interferometric SAR (InSAR) analysis using ALOS/PALSAR data to a megathrust earthquake (Mw 9.0) that ruptured off-shore of Tohoku, Japan, on 11 March, 2011, we succeeded in mapping a ground displacement distributed over ~600 km range in the north-south orientation and ~200 km range in the east-west orientation. A relative slant range lengthening of ~4 m that is the largest displacement ever observed in Japan on InSAR records was detected at the tip of Oshika peninsula, consistent with GPS observations. The interferograms, calculated using quick but less accurate orbit data, are contaminated by long-wavelength noise, preventing us from measuring the correct ground displacement. We demonstrate that an InSAR analysis incorporating GEONET data effectively reduces noise and enables the prompt and accurate mapping of the ground displacement. Additionally, a clear coseismic signal due to an inland earthquake in northern Ibaraki on 19 March, 2011 (Mj 6.1) was also detected. Our preferred fault model assuming two segments shows a nearly pure normal fault motion with a west-dipping fault plane. The ACFF calculation suggests that the Mw 9.0 main shock promoted the Mj 6.1 event.

Daytime meteorological structures causing elevated photochemical oxidants concentrations in north Kanto, Japan

The north Kanto area is about 150 km north of the heavily populated and industrialized Tokyo metropolis, and local emissions of photochemical oxidants (Ox) precursors are limited because of little anthropogenic emission. Nevertheless, high Ox concentrations exceeding the warning level for Ox (>120 ppbv, 1-h average) are often observed there. We recently reported that high Ox concentrations in the north Kanto area occur under the coupled conditions of a southerly extended sea breeze transporting Ox from the southern urban area and a subsidence inversion layer restricting vertical dispersion. However, these meteorological conditions do not always lead to high Ox concentrations. To identify other conditions affecting the occurrence of high Ox concentrations in north Kanto, we examined meteorological conditions. Key meteorological structures were two thermal lows occurring on sunny days in districts neighboring the Kanto district on the west and north. When both thermal lows persisted in their morning positions until evening, a southerly sea breeze toward the thermal lows was maintained throughout the afternoon, transporting high levels of Ox formed in south Kanto, including Tokyo, to north Kanto. When a thermal low present only in the western district moved eastward to cover the central Kanto area during the afternoon, isobars in north Kanto acquired an east–west orientation and observed wind direction became consistently northerly, thus restricting transport of high Ox from south Kanto.

In Situ Stresses in Borehole Blanche-1/South Australia Derived from Breakouts, Core Discing and Hydraulic Fracturing to 2 km Depth

The development of Hot-Dry Rock (HDR) geothermal energy in Australia with drillings to some kilometres depth yields an impetus for deep stress logging. For the Olympic Dam HDR-project, borehole Blanche-1 was drilled to almost 2 km depth and provided the possibility to estimate the in situ stresses within the granitic borehole section by the analysis of borehole breakouts and core discing, as well as by hydraulic fracturing combined with acoustic borehole televiewer logging for fracture orientation determination. Although the stress magnitudes derived by the different methods deviate significantly, they clearly indicate for the depth range between 800 and 1,740 m a compressional stress regime of Sv ≤ Sh < SH and a consistent East–West orientation of maximum horizontal compression in agreement with existing stress data for Australia. The minor horizontal stress Sh derived from the hydraulic fracturing closure pressure values is about equal to the overburden stress and may be regarded as most reliable.

Optical and thermal optimization of stationary non-evacuated CPC solar concentrator with fully illuminated wedge receivers

Stationary low concentrator collectors ( C < 2), of the CPC type, are of great interest for thermal energy supply of industrial processes, at temperatures below or equal to 100 °C. In particular, concentrators with fully illuminated V inverted absorbers have attractive properties for thermal energy conversion. Numerical analysis of the geometric and optical characteristics of different low concentration CPC’s ( C between 1 and 2) with fully inverted wedge absorbers, shows that the cavities with the minimal relationship between the length and height of the reflector surface and the aperture, ( L/ A) and ( H/ A), and the lower average number of reflections 〈 n〉 correspond to the lowest angular acceptance concentrator. If a concentration of 1.2 is desired, the smallest ratios of ( L/ A) and ( H/ A) and mean number of reflections 〈 n〉 occur for C = 2 ( θ a = 30°). However, when the annual generated thermal energy is also considered (for example, for Recife, tilt equals latitude, fluid temperature equals 50 °C, East–West orientation), a very large maximum value in the concentration region between 1.4 and 1.6 (acceptance angles of 38.68° e 45.58°) occurs. The simulation results indicate, that while the operational temperature rises, the ratio between the annual generated thermal energy by the CPC and a good quality flat-plate collector becomes greater than 1: for CPC with 1.2 concentration these ratios become 1.0 at 50 °C and 1.35 at 80 °C. The improvement in the reflectivity of the reflector surface of the CPC rises significantly this relation, i.e., if the reflectivity exceeds from 0.86 to 0.96 the CPC of the concentration relation 1.2, operating at 80 °C may generate 55% more thermal energy than flat-plate collector.

Effect of Vineyard Row Orientation on Growth and Phenology of Glyphosate-Resistant and Glyphosate-Susceptible Horseweed (Conyza canadensis)

Horseweed has become increasingly common and difficult to control in San Joaquin Valley vineyards, due in part, to the evolution of glyphosate resistance. The development of weed-suppressive vineyard designs in which the trellis design, spacing, and row orientation combine to cast dense shade on the weed canopy zone (WCZ) may reduce weed growth. The relevance of such a system to horseweed, which can grow to be as tall, or taller, than a typical grapevine trellis, is uncertain. Also unknown is whether a glyphosate-resistant (GR) biotype and glyphosate-susceptible (GS) biotype would perform similarly under such conditions. Therefore, we compared the growth and development of two potted horseweed biotypes (GR and GS) in vinerows oriented east–west (EW) and north–south (NS). Rows oriented EW allowed less light penetration to the WCZ than NS rows throughout the study, and horseweed biotypes responded to low light levels by producing leaves with larger specific leaf area and leaf area ratios than those in the NS rows. Also, the leaf, stem, and root dry weight of the horseweed plants in the EW rows was reduced by 30% compared to the horseweed plants in NS rows. Leaf number was also reduced in the horseweed plants in the EW rows, but only for the GS biotype. Row orientation did not affect phenological development or the number of seeds produced by the GR or GS biotypes, but the GR biotype budded, flowered, and set seed approximately 1 wk earlier than the GS biotype. Thus, shade associated with the EW vinerows reduced horseweed growth, but not fecundity, and the GR biotype reached reproductive maturity earlier than the GS biotype.

Exploring the spatial distribution of light interception and photosynthesis of canopies by means of a functional-structural plant model.

At present most process-based models and the majority of three-dimensional models include simplifications of plant architecture that can compromise the accuracy of light interception simulations and, accordingly, canopy photosynthesis. The aim of this paper is to analyse canopy heterogeneity of an explicitly described tomato canopy in relation to temporal dynamics of horizontal and vertical light distribution and photosynthesis under direct- and diffuse-light conditions. Detailed measurements of canopy architecture, light interception and leaf photosynthesis were carried out on a tomato crop. These data were used for the development and calibration of a functional-structural tomato model. The model consisted of an architectural static virtual plant coupled with a nested radiosity model for light calculations and a leaf photosynthesis module. Different scenarios of horizontal and vertical distribution of light interception, incident light and photosynthesis were investigated under diffuse and direct light conditions. Simulated light interception showed a good correspondence to the measured values. Explicitly described leaf angles resulted in higher light interception in the middle of the plant canopy compared with fixed and ellipsoidal leaf-angle distribution models, although the total light interception remained the same. The fraction of light intercepted at a north-south orientation of rows differed from east-west orientation by 10 % on winter and 23 % on summer days. The horizontal distribution of photosynthesis differed significantly between the top, middle and lower canopy layer. Taking into account the vertical variation of leaf photosynthetic parameters in the canopy, led to approx. 8 % increase on simulated canopy photosynthesis. Leaf angles of heterogeneous canopies should be explicitly described as they have a big impact both on light distribution and photosynthesis. Especially, the vertical variation of photosynthesis in canopy is such that the experimental approach of photosynthesis measurements for model parameterization should be revised.

Design scenarios for flat panel photobioreactors

Evaluation of the potential of algae production for biofuel and other products at various locations throughout the world requires assessment of algae productivity under varying light conditions and different reactor layouts. A model was developed to predict algae biomass production in flat panel photobioreactors using the interaction between light and algae growth for the algae species Phaeodactylum tricornutum and Thalassiosira pseudonana. The effect of location, variable sunlight and reactor layout on biomass production in single standing and parallel positioned flat panels was considered. Three latitudes were studied representing the Netherlands, France and Algeria. In single standing reactors the highest yearly biomass production is achieved in Algeria. During the year biomass production fluctuates the most in the Netherlands, while it is almost constant in Algeria. Several combinations of path lengths and biomass concentrations can result in the same optimal biomass production. The productivity in parallel place flat panels is strongly influenced by shading and diffuse light penetration between the panels. Panel orientation has a large effect on productivity and at higher latitudes the difference between north–south and east–west orientation may go up to 50%.

Methodology to Analyze Sun Glare Impact on Highway under Prolonged Exposure

Sun glare may impair drivers’ vision on a particular road section while driving. Recently, a new method has been developed for analyzing the problem on specific road elements. This method does not account for the prolonged glare exposure, which occurs when the sun position lies uninterruptedly within the driver’s field of vision for an extended period of time along a highway segment. In this article a new methodology for carrying out the analysis of glare problems in road segments under conditions of prolonged glare exposure is presented. The methodology can be applied to both existing roads and new road designs, either for analyzing the impact of prolonged sun glare on drivers or for the design of measures against the sun’s glare. An application to a 45-km long road segment with east-west orientation is presented.

Manipulating Crop Row Orientation to Suppress Weeds and Increase Crop Yield

Crop rows oriented at a right angle to sunlight direction (i.e., east–west within the winter cropping system in Western Australia) may suppress weed growth through greater shading of weeds in the interrow spaces. This was investigated in the districts of Merredin and Beverley, Western Australian (latitudes of 31° and 32°S) from 2002 to 2005 (four trials). Winter grain crops (wheat, barley, canola, lupines, and field peas) were sown in an east–west or north–south orientation. Within wheat and barley crops oriented east–west, weed biomass (averaged throughout all trials) was reduced by 51 and 37%, and grain yield increased by 24 and 26% (compared with crops oriented north–south). This reduction in weed biomass and increase in crop yield likely resulted from the increased light (photosynthetically active radiation) interception by crops oriented east–west (i.e., light interception by the crop canopy as opposed to the weed canopy was 28 and 18% greater in wheat and barley crops oriented east–west, compared with north–south crops). There was no consistent effect of crop row orientation in the canola, field pea, and lupine crops. It appears that manipulation of crop row orientation in wheat and barley is a useful weed-control technique that has few negative effects on the farming system (i.e., does not cost anything to implement and is more environmentally friendly than chemical weed control).

Influence of fractures on the development of low-permeability sandstone reservoirs: A case study from the Taizhao district, Daqing Oilfield, China

This paper studies the influence of fracture on the development of low-permeability sandstone reservoirs. There are four assemblages of high angle tectonic fractures assuming east–west, south–north, northwest–southeast and northeast–southwest strikes respectively in the Putaohua oil layer of the Taizhao district, leading to a gradual weakening in their development. In light of the influences of the present-day stress field, the east–west fractures are considered to have the best connectedness, the biggest aperture, the highest permeability and the lowest opening pressure, present the main channel for fluid flow in the low-permeability sandstone reservoirs. These fractures impact on the well pattern deployment, water injection and hydraulic fracturing in the low-permeability sandstone reservoirs. Based on the distribution and flow characteristics of fractures, favorable effects can be obtained by rectangular and rhombus well patterns along the principal seepage fractures of the east–west orientation in the primary period of development. Due to their minimum opening pressure, the east-west fractures are the earliest to open during the water flooding development, so we should control the injection pressure under the open pressure of east–west fractures. Artificial fractures formed by hydraulic fracturing in low-permeability sandstone reservoirs are controlled by natural fractures and the presented-day stress. If the angle between natural fractures and the present-day stress is less than the critical angle, the artificial fractures extend mainly along the natural fractures and do not generate new fractures. If the angle between natural fractures and the present-day stress is bigger than the critical angle, the artificial fractures extend vertically to the minimum stress ( σ 3) of the present-day stress field. These results demonstrate the importance of assessing the fracture distribution in the low-permeability sandstone reservoirs.

Experimental study of a multi-tube ICS solar water heating system in mild climates

Since a majority of residential and industrial building hot water needs are around 50°C, an integrated solar water heater could provide a bulk source that blends collection and storage into one unit. These collectors incorporate thermal storage within the collector itself. The storage pipe surface serves as the absorber surface. Most ICS systems use only one tank, but some use a number of tanks in series. While the simplicity of ICS systems is attractive, they are generally suitable only for applications in mild climates with small thermal storage requirements. A multi-tube ICS solar hot water system with eight cylindrical water storage tanks (pipes) in horizontal (East-West) orientation was designed and outdoor tests of experimental model were performed in mild climate of north (Caspian Sea) region of Iran. Experimental results such as water temperature profiles, mean daily efficiency, water temperature stratification and thermal losses during night are presented and discussed for this model. Experimental results showed that the daily mean efficiency is comparable to other ICS systems and also acceptable thermal performance of this type of ICS system has been observed.

Evolution of Neogene volcanism and stress patterns in the glaciated West Antarctic Rift, Marie Byrd Land, Antarctica

Abstract: The orientations and ages of polygenetic volcano chains, elongate volcano edifices, and elongate summit calderas in Marie Byrd Land, Antarctica, are analysed to determine stress directions during volcanism and coeval glaciation across the West Antarctic Rift. Initiation of volcanism c . 36–34 Ma and major polygenetic volcanism beginning c . 14 Ma are broadly coeval with establishment of significant ice volumes in West Antarctica. Middle–Late Miocene volcanism occurred primarily along roughly north–south volcano chains, whereas latest Miocene–Pleistocene volcanism had a strong east–west preferred orientation across the spatial extent of the province. Anisotropic stress conditions controlled both phases of volcanism, and a rapid rotation in the maximum horizontal stress direction from north–south to east–west occurred as early as c . 6 Ma. Glacial loading and unloading appears to have facilitated volcanism in Marie Byrd Land, but ice margin reconstructions make it unlikely that stress field rotation is a result of flexural stresses imposed by glacial loading cycles. The east–west orientation of latest Miocene to Pleistocene maximum horizontal stress is parallel to the absolute motion of the Antarctic plate for the past 6 Ma, and the north–south to east–west stress field rotation coincides with changes in Antarctic–Pacific Ridge spreading and Pacific basin tectonic events associated with plate reorganization.

Climate–growth relationships of Qilian juniper Sabina przewalskii in the Anyemaqen Mountains, Tibet

Climate-growth relationships were investigated for 5 mountain slopes of the Anye- maqen Mountains on the northeastern Tibetan Plateau, using a tree-ring width network indicating the chronologies of 20 Qilian junipers Sabina przewalskii. Tree growth is mainly controlled by regional climate conditions, which are modulated by altitudinal factors. The tree growth patterns in this region were classified asccording to a west-east orientation. Temperature and precipitation from August to October of the previous year and May of the current year are the major limiting factors for most chronologies, as indicated by simple correlation analysis. In general, precipitation plays a more important role in governing tree growth than temperature, and tree rings in the east are more sensi- tive to precipitation than those in the west. Differences in the climate-growth relationship may be caused by varying climate conditions between the western and eastern Anyemaqen Mountains.

Depositional sequences in a foreland basin (north-western domain of the continental Duero basin, Spain)

The Cenozoic record of the north-western domain of the Duero basin is articulated at the surface through a set of continental depositional sequences called, from base to top, the Vegaquemada sequence, the Candanedo sequence, and the Barrillos sequence. These depositional sequences were deposited in continental sedimentary environments. The deposition of the first sequence occurred through a fluvial system with floodplains cut by low-sinuosity channels. The Vegaquemada sequence was developed between the Middle Eocene and the Early Agenian. The second sequence was formed by a set of highly efficient transport alluvial fans that evolved laterally towards fluvial systems with low-sinuosity fluvial channels and an extensive floodplain, where several types of palaeosols were formed. This sequence developed between the Early Agenian and the Late Vallesian. The third unit–the Barrillos sequence (between the Late Vallesian and the Turolian/Ruscinian transition), was generated by a set of highly efficient transport alluvial fans dominated by low-sinuosity fluvial channels. In subsurface geology, seismic and well data are used to rebuild the stratigraphic architecture. The two basal depositional sequences can be identified with two seismic units: the Palaeogene Seismic Unit (PgSU) and the Neogene Seismic Unit (NgSU), respectively. In the present work, we obtained the isovelocity, isochron, and isobath maps for the top and base of the two Cenozoic units. The Palaeozoic (PzSU) and Mesozoic (MzSU) seismic units are found under these two units. Through study of the logs of the various boreholes, it was only possible to analyse the upper 700 m of the Candanedo Sequence (NgSU), without encompassing the total thickness of the unit. Several middle-order sequences were differentiated, in general showing a sequential fining-upwards evolutionary character. Additionally, for the boreholes analysed two main types of electrofacies were identified, both representing fluvial channels and floodplain deposits. The north-western domain of the Duero basin is interpreted to have been formed in response to the tectonic uplifting of the Cantabrian Mountains since Middle-Eocene times. Integration of the data concerning the surface and subsurface geology in this domain reveals that this basin edge behaved as a foreland basin during Cenozoic stages. The foredeep, with a depth of 2800 m, is oriented east–west and has a sediment thickness of up to 3500 m. The forebulge is located in the southwestern zone and represents an area of basement uplifting in which a minimum thickness of materials from the Cenozoic depositional sequences has accumulated.