scholarly journals High Resolution Seismic Reflection Methods to Detect Near Surface Tuff-Cavities: A Case Study in the Neapolitan Area, Italy

2013 ◽  
pp. 51-59 ◽  
Author(s):  
Vincenzo Di Fiore ◽  
Antimo Angelino ◽  
Salvatore Passaro ◽  
Angelo Bonanno
Keyword(s):  
High Resolution ◽  
Seismic Reflection ◽  
Near Surface

scholarly journals High-resolution shear-wave seismic reflection as a tool to image near-surface subrosion structures – a case study in Bad Frankenhausen, Germany

Solid Earth ◽  
2016 ◽  
Vol 7 (5) ◽  
pp. 1491-1508 ◽  
Author(s):  
Sonja H. Wadas ◽  
Ulrich Polom ◽  
Charlotte M. Krawczyk
Keyword(s):  
High Resolution ◽  
Shear Wave ◽  
Urban Areas ◽  
Seismic Reflection ◽  
Seismic Velocities ◽  
Horizontal Shear ◽  
Near Surface ◽  
Seismic Sections ◽  
The Church

Abstract. Subrosion is the subsurface leaching of soluble rocks that results in the formation of depression and collapse structures. This global phenomenon is a geohazard in urban areas. To study near-surface subrosion structures, four shear-wave seismic reflection profiles, with a total length of ca. 332 m, were carried out around the famous leaning church tower of Bad Frankenhausen in northern Thuringia, Germany, which shows an inclination of 4.93° from the vertical. Most of the geological underground of Thuringia is characterized by soluble Permian deposits, and the Kyffhäuser Southern Margin Fault is assumed to be a main pathway for water to leach the evaporite. The seismic profiles were acquired with the horizontal micro-vibrator ELVIS, developed at Leibniz Institute for Applied Geophysics (LIAG), and a 72 m long landstreamer equipped with 72 horizontal geophones. The high-resolution seismic sections show subrosion-induced structures to a depth of ca. 100 m and reveal five features associated with the leaching of Permian deposits: (1) lateral and vertical varying reflection patterns caused by strongly heterogeneous strata, (2) discontinuous reflectors, small offsets, and faults, which show the underground is heavily fractured, (3) formation of depression structures in the near-surface, (4) diffractions in the unmigrated seismic sections that indicate increased scattering of the seismic waves, and (5) varying seismic velocities and low-velocity zones that are presumably caused by fractures and upward-migrating cavities. A previously undiscovered southward-dipping listric normal fault was also found, to the north of the church. It probably serves as a pathway for water to leach the Permian formations below the church and causes the tilting of the church tower. This case study shows the potential of horizontal shear-wave seismic reflection to image near-surface subrosion structures in an urban environment with a horizontal resolution of less than 1 m in the uppermost 10–15 m.

Near-Surface Cavity Detection By High-Resolution Seismic Reflection Methods Using Short-Spacing Type Land Streamer

2005 ◽  
Author(s):  
Tomio Inazaki ◽  
Shigeki Kawamura ◽  
Oshie Tazawa ◽  
Yoshihiro Yamanaka ◽  
Naomi Kano
Keyword(s):  
High Resolution ◽  
Seismic Reflection ◽  
Short Spacing ◽  
Near Surface ◽  
Cavity Detection ◽  
Surface Cavity

scholarly journals Potential of high-resolution detection and retrieval of precipitation fields from X-band spaceborne synthetic aperture radar over land

2011 ◽  
Vol 15 (3) ◽  
pp. 859-875 ◽  
Author(s):  
F. S. Marzano ◽  
S. Mori ◽  
M. Chini ◽  
L. Pulvirenti ◽  
N. Pierdicca ◽  
...  
Keyword(s):  
High Resolution ◽  
Spatial Resolution ◽  
Rain Rate ◽  
Central Italy ◽  
Synthetic Aperture ◽  
Simple Method ◽  
Near Surface ◽  
Orographic Rainfall ◽  
X Band

Abstract. X-band Synthetic Aperture Radars (X-SARs), able to image the Earth's surface at metric resolution, may provide a unique opportunity to measure rainfall over land with spatial resolution of about few hundred meters, due to the atmospheric moving-target degradation effects. This capability has become very appealing due to the recent launch of several X-SAR satellites, even though several remote sensing issues are still open. This work is devoted to: (i) explore the potential of X-band high-resolution detection and retrieval of rainfall fields from space using X-SAR signal backscattering amplitude and interferometric phase; (ii) evaluate the effects of spatial resolution degradation by precipitation and inhomogeneous beam filling when comparing to other satellite-based sensors. Our X-SAR analysis of precipitation effects has been carried out using both a TerraSAR-X (TSX) case study of Hurricane "Gustav" in 2008 over Mississippi (USA) and a COSMO-SkyMed (CSK) X-SAR case study of orographic rainfall over Central Italy in 2009. For the TSX case study the near-surface rain rate has been retrieved from the normalized radar cross section by means of a modified regression empirical algorithm (MREA). A relatively simple method to account for the geometric effect of X-SAR observation on estimated rainfall rate and first-order volumetric effects has been developed and applied. The TSX-retrieved rain fields have been compared to those estimated from the Next Generation Weather Radar (NEXRAD) in Mobile (AL, USA). The rainfall detection capability of X-SAR has been tested on the CSK case study using the repeat-pass coherence response and qualitatively comparing its signature with ground-based Mt. Midia C-band radar in central Italy. A numerical simulator to represent the effect of the spatial resolution and the antenna pattern of TRMM satellite Precipitation Radar (PR) and Microwave Imager (TMI), using high-resolution TSX-retrieved rain images, has been also set up in order to evaluate the rainfall beam filling phenomenon. As expected, the spatial average can modify the statistics of the high-resolution precipitation fields, strongly reducing its dynamics in a way non-linearly dependent on the rain rate local average value.

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