From a great variety of in situ shear wave experiments, i.e., reflection, refraction and borehole surveys in the shallow sediments of the north German plains, several specific properties have been derived. Shear waves (S) differ from compressional waves (P) in that:1. they are not affected by the degree of water saturation. Thus, they provide a better correlation between the velocity V, and (solid) lithology ; 2. they generally have lower frequencies, but shorter wavelength and, hence, a better resolution of thin layers; 3. they have lower absorption Qs-' and hence a better penetration in partially saturated and gas-containing sediments than P-waves.Correlations have been established between V, and the confining pressure and between reduced V, values and several lithological parameters like the grain size of sandy material.More lithological and hydrological information is obtained by using S-and P-wave surveys along the same profile. The best information on a sedimentological structure is obtained by the simultaneous observation of V,, V,, Q, and Q, .

The prehistoric shell middens of Atlantic Europe consist of marine molluscs, but the eastern Baltic did not have exploitable marine species. Here the sole recorded shell midden, at Riņņukalns in Latvia, is on an inland lake and is formed of massive dumps of freshwater shells. Recent excavations indicate that they are the product of a small number of seasonal events during the later fourth millennium BC. The thickness of the shell deposits suggests that this was a special multi-purpose residential site visited for seasonal aggregations by pottery-using hunter-gatherer communities on the northern margin of Neolithic Europe.

The city of Iznik, called Nikaia or Nicaea in ancient times, is located in northwest Anatolia, Turkey. Nicaea is renowned especially for the first Council of Nicaea convened by the Roman emperor Constantine in AD 325 in an attempt to unify the Church. During an international field course on the geophysical exploration of archaeological targets we detected the remains of a small previously unknown Byzantine church on a fallow lot of land inside the city. The church is oriented parallel to the ancient Hippodamian street grid that deviates from the modern street system of the quarter by~45°. We found the contours of the nave, two aisles and three apses as well as evidence of a partly refilled grave. The geophysical measurements indicate that the foundations of the church consist of low-porosity hard rock with a low magnetic susceptibility, probably limestone or sandstone embedded in fluvial sediments. The field study is based on ground-penetrating radar (GPR), magnetics, electric resistivity tomography (ERT) and microgravimetry. It highlights the strength and necessity of combining different geophysical methods in exploring and characterizing archaeological sites. In fact, the foundation walls of the church do not show any magnetic anomaly but could be delineated clearly only by GPR. The wall remains appear as highly resistive spots in ERT. By converting the three-dimensional GPR image into an electric resistivity model we could verify that the ERT results fully correspond to the ruins found by GPR. The structure interpreted as a loosely refilled grave is indicated mainly by a weak gravity anomaly (~9 μGal) and a diffuse reflection pattern in GPR. Electric forward modelling shows that this structure leads to an additional increase of a high resistivity anomaly, which is primarily caused by foundation rocks, but it cannot be resolved within the ERT pattern a priori.

We present the results of a shear-wave reflection experiment and in situ measurements in opencast lignite exploration. Near-surface coal seams have lower shear-wave velocities ( z 200 m/s) and lower densities than sand and clay layers. Due to strong reflection coefficients, a shear-wave reflection survey provides a powerful tool in lignite prospecting. Due to shorter seismic wavelengths shear waves will yield a higher resolution of shallow subsurface structure than compressional waves. Low shear-wave velocities and strong lateral velocity variations, however, require a dense data acquisition in the field. The variation of stacking velocities can exceed & 15% within a profile length of 300 m. The different steps in processing and interpretation of results are described with actual records. The final CMP-stack shows steep-angle fault zones with maximum dislocations of 20 m within a coal seam.

We show an extensive multimethod geophysical study of focusing on some enigmatic subsurface structures found at Ancient Aigeira (N Peloponnes, Greece) that could be interpreted either as prehistoric chamber tombs or complex weathering patterns of the local marl–conglomerate rock sequences. It turns out that the nonseismic methods do not allow to distinguish between an archaeological and a geological origin of the observed patterns with certainty. In contrast, we demonstrate how shear‐wave seismics and full‐waveform inversion (FWI) can be used in archaeological prospection for distinguishing between these alternative essentially different interpretational models that are not distinguishable through nonseismic prospection data. The example site Aigeira is strategically well located on a hill on the Northern Peloponnese overlooking the Corinthian Gulf and has been inhabited with occupational gaps since Middle Neolithic times until the 12th to early 14th century ce. Magnetics, ground‐penetrating radar (GPR) and electrical resistivity tomography (ERT) reveal a honeycomb‐shaped anomaly pattern that could have been interpreted as a system of prehistoric chamber tombs. The time‐domain SH‐FWI strategy based on a sequential inversion of low‐pass and band‐pass filtered data results in subsurface models for shear‐wave velocity and density that accurately fits the complicated seismic data set. A highly heterogeneous subsurface is revealed that is characterized by linear cracks on a decimetre scale. The seismic FWI results are compared in detail with GPR, ERT and among each other. It turns out that the FWI result is consistent with each of these other geophysical methods but provides a more comprehensive subsurface characterization that it is supported by corings in addition. With the help of the seismic survey, we can reject the interpretation hypothesis of a prehistoric cemetery with chamber tombs and confirm that the enigmatic geophysical patterns represent a geological weathering structure that could be addressed as a reincised fan delta draped by reddish palaeosols.