Browsing by Author "Henkel, H"

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item: Conference-Full-text
Modeling simple craters using gravity measurements
(Department of Earth Resources Engineering, 2010-09) Henkel, H; Ekneligoda, TC; Ratnayake, NP; Abeysinghe, AMKB; Premasiri, HMR; Karunaratne, S
A study was carried out for two early Paleozoic impact structures in Sweden. These two impact structures (Granby and Tvaren) are located in the southern part of Sweden. Common features can be identified of these two structures as similar diameter of ca 2 km and a substantial post impact fill with Paleozoic sedimentary rocks. The Granby structure represents an almost completely preserved impact crater within a Paleozoic sedimentary rock sequence — only the uppermost part of the raised crater rim might be eroded and was subsequently covered by Quaternary sediments. The Tvaren structure is eroded below the surrounding pre-impact Paleozoic cover rocks into the underlying crystalline basement and has a Quaternary sediment fill. Gravity measurements were carried out on land and sea ice. The inverse gravity modeling shows a gradual change of density and the equivalent porosity with radial distance from the explosion center within the damage zone around and below simple craters.
item: Article-Full-text
The spacing calculator software - A Visual Basic program to calculate spatial properties of lineaments
(Elsevier, 2006) Ekneligoda, TC; Henkel, H
A software tool is presented which calculates the spatial properties azimuth, length, spacing, and frequency of lineaments that are defined by their starting and ending co-ordinates in a two-dimensional (2-D) planar co-ordinate system. A simple graphical interface with five display windows creates a user-friendly interactive environment. All lineaments are considered in the calculations, and no secondary sampling grid is needed for the elaboration of the spatial properties. Several rulebased decisions are made to determine the nearest lineament in the spacing calculation. As a default procedure, the programme defines a window that depends on the mode value of the length distribution of the lineaments in a study area. This makes the results more consistent, compared to the manual method of spacing calculation. Histograms are provided to illustrate and elaborate the distribution of the azimuth, length and spacing. The core of the tool is the spacing calculation between neighbouring parallel lineaments, which gives direct information about the variation of block sizes in a given category of structures. The 2-D lineament frequency is calculated for the actual area that is occupied by the lineaments
item: Conference-Full-text
Spatial properties of lineaments using a computer software
(Department of Earth Resources Engineering, 2010-09) Ekneligoda, TC; Henkel, H; Ratnayake, NP; Abeysinghe, AMKB; Premasiri, HMR; Karunaratne, S
An interactive software, Spatial Analysis of Lineaments, has been developed, that calculates the spatial properties azimuth, length, spacing, and unidirectional frequency of lineaments, provided that the starting and end coordinates of the lineaments are given. The software accepts a large number of lineaments. The different statistical properties are derived in series of steps and spatial outliers are removed in an interactive way. The software allows the user to sub-divide the azimuth group in to two or more if necessary. The nearest lineament is found based on the rules developed by Ekenligoda, & Henkel, 2004. The results are presented in graphical form for all spatial properties mentioned above together with mean, mode and standard deviation of each property and the number of lineaments involved for the derivation of spatial properties and the unidirectional lineament frequency.