ALBERT

Description: The Padul-Nigüelas Fault Zone (PNFZ) is situated at the south-western mountain front of the Sierra Nevada (Spain) in an extensive regime and belongs to the internal zone of the Betic Cordilleras. The aim of this study is a collection of new evidence for neotectonic activity of the fault zone with classical geological field work and modern geophysical methods, such as ground penetrating radar (GPR). Among an apparently existing bed rock fault scarp with triangular facets, other evidences, such as deeply incised valleys and faults in the colluvial wedges, are present in the PNFZ. The preliminary results of our recent field work have shown that the synsedimentary faults within the colluvial sediments seem to propagate basinwards and the bed rock fault is only exhumed due to erosion for the studied segment (west of Marchena). We will use further GPR data and geomorphologic indices to gather further evidences of neotectonic activity of the PNFZ.

Description: Ground penetrating radar (GPR) and capacitive coupled resistivity (CCR) measurements were conducted in order to image subsurface structures in the Orkhon Valley, Central Mongolia. The data are extended by information from drill cores to the entire transects distinguishing different sedimentary environments in the valley. The Orkhon Valley is part of the high sensitive Steppe region in Central Mongolia, one of the most important cultural landscapes in Central Asia. There, archaeological, geoarchaeological and sedimentological research aims to reconstruct the landscape evolution and the interaction between man and environment during the last millennia since the first settlement. In May 2009 and 2010 geophysical surveys have been conducted including transects with lengths between 1.5 and 30 km crossing the entire valley and a kilometre-scaled grid in the southern part of the investigation area. The geoelectrical and GPR data revealed the existence of two layers characterized by different resistivity values and radar reflectors. The two layers do not only represent material contrasts, but also reflect the influence of sporadic permafrost which occurs in several areas of Mongolia. The results help to reconstruct the evolution of the braided Orkhon River and therefore give important hints to understand the environmental history of the Orkhon Valley.

Description: This dataset contains details of 15 samples of the river terraces that were collected along the banks of the Greater Zab River (Kurdistan Region of Iraq) that crosses the Zagros Fold-Thrust Belt. These terraces were dated using luminescence dating including both Infrared Stimulated Luminescence (IRSL) and post-IR IRSL (pIR) to determine their depositional ages. The dataset includes details about the locations, dosimetry, and determined ages of the collected samples. The ages of the dated river terraces range from c. 165 ka to c. 6 ka. The terraces were deposited at the river level. Their present-day elevation above the river is interpreted as the amount of incision by the river that occurred in response to the uplift. The uplift rates of river terraces were integrated with kinematic modeling of the fault-related fold belt in the area to calculate long-term slip rates during the Late Pleistocene to Holocene. Our results provide new insight into the rates of active faulting and folding in the area. The Zagros Mountain Front Fault accommodates about 1.46±0.60 mm a-1 of slip, while a more external basement fault further to the SW accommodates less than 0.41±0.16 mm a-1. Horizontal slip rates related to detachment folding of two anticlines within the Zagros Foothills are 0.40±0.10 and 1.24±0.36 mm a-1, respectively.

Description: Dilatant faults often form in rocks containing pre-existing joints, but the effects of joints on fault segment linkage and fracture connectivity is not well understood. We present an analogue modeling study using cohesive powder with pre-formed joint sets in the upper layer, varying the angle between joints and a rigid basement fault. We analyze interpreted map-view photographs at maximum displacement for damage zone width, number of connected joints, number of secondary fractures, degree of segmentation and area fraction of massively dilatant fractures. Particle imaging velocimetry helps provide insights on deformation history of the experiments and illustrate the localization pattern of fault segments. Results show that with increasing angle between joint-set and basement-fault strike the number of secondary fractures and the number of connected joints increases, while the area fraction of massively dilatant fractures shows only a minor increase. Models without pre-existing joints show far lower area fractions of massively dilatant fractures while forming distinctly more secondary fractures.

Description: The transition zone between the Southern Eastern Alps and the Dinarides is situated in western Slovenia and northeastern Italy. Here, a system of mainly NW-SE trending, right-lateral strike-slip faults accommodates the shortening between the Adriatic Plate and Eurasia. Due to the low deformation rates, geodetic techniques and seismology provide only limited insights into the activity of those faults. Geomorphological studies are confronted with problems arising from the low fault slip rates, distributed deformation, and unfavourable conditions due to the karst environment. One way to overcome these problems is the use of paleoseismology, i.e. the excavation of active faults to study their earthquake history and slip behaviour. A prerequisite for paleoseismological trenching is knowledge on the precise location of the fault trace and the availability of a suitable sediment record. We performed geophysical surveys across the potentially active faults in Slovenia and Italy to select sites for paleoseismic trenching. We used a ground-penetrating radar (GPR) system from Geophysical Survey Systems Inc (GSSI) with monostatic 100 MHz, 270 MHz, and 400 MHz antennas and a Pulse EKKO Pro Sensors & Software system equipped with bistatic 250 MHz antennas. All data were processed with the ReflexW software (Sandmeier Geophysical Research). Processing included frequency bandpass filtering, background removal, gain adjustments, and topographic corrections. The topographic data were extracted from the 1 m DEM. Electric resistivity tomography (ERT) was performed with a 4-point-light system (Lippmann Geophysikalische Messgeräte). We used up to 80 electrodes with varying electrode spacing for Wenner, Schlumberger, and Dipole-Dipole arrays, depending on target resolution and depth. Data inversion was done with Res2DInv (Geotomo Software) and included manual de-spiking and topographic corrections. Along several profiles we measured the vertical gradient of the geomagnetic field and the total magnetic field strength with a proton magnetometer GSM - 19T (GEM Systems). The system consists of a rover and a base station, which allows correcting the data for diurnal variation. Depending on the equipment used and the survey parameters, these methods allow insights into the first few metres of the subsurface with a resolution of few centimetres (georadar) to a few metres (ERT). We focussed on sites that host Quaternary sediments. Most of the data in this dataset are 2D profiles perpendicular to the mapped traces of active faults. Several promising sites were investigated in 2.5D, i.e. the profile line spacing was dense enough to compute a pseudo-3D dataset. We collected the data in May and June, 2018. This dataset contains ~2.5 km of magnetic data, ~20 km of GPR data, and ~1.7 km of ERT data. This work was undertaken for the DFG project "Earth surface response to Quaternary faulting and shallow crustal structure in the eastern Adria-Alpine collision zone and the Friulian plain" within the DFG-funded priority programme SPP2017 - Mountain building processes in 4D.

Description: Southern Spain is a seismically active area due to the boundary between the Eurasian and African plates. The Roman Ruins of Baelo Claudia at the Strait of Gibraltar host an archaeological record of at least two destructive earthquakes in Roman times. Furthermore, there is geological evidence for severe tsunami impact along the coast. We conducted an extensive georadar survey within the ruins in order to map geological evidence for ground shaking and to trace earthquake damage horizons. The data also have the potential to reveal tsunami layers within the archaeological site. In 2006, we used GSSI 300 MHz and low-frequency 240 cm antennas with a GSSI SIR-2 field computer to collect several kilometres of georadar data. The data also reveal hidden archaeological objects such as ancient roads and walls. This dataset contains three folders: - ascii: rawdata in *.dzt format - rawdata: data imported to ReflexW format, trace interpolation based on 1 m-spaced markers - images: jpg files of the processed data We also include: - a ReadMe file - a map with the location of the profiles - an ExcelSheet with details on every georadar profile