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11.
Subsidence curves from Mesozoic sedimentary basins at the southern Iberian margin (Betic Cordilleras) display pronounced changes in subsidence rates around 85 Ma (chron 34, Late Cretaceous, Santonian to earliest Campanian). The subsidence events correlate with changes in the bulk and clay mineral composition in these basins, as well as with an Eoalpine high-pressure metamorphic event in the western Mediterranean region. The synchroneity with subsidence events observed in basins around the Iberian microplate suggests a causal relationship with the regional plate tectonic setting. We propose that the circum-Iberian subsidence event was largely controlled by the convergence and incipient collision of the Iberian microplate with Africa. 相似文献
12.
Frenken Mike Bellanova Piero Nishimura Yuichi Reicherter Klaus Schwarzbauer Jan 《Natural Hazards》2022,114(1):313-333
Natural Hazards - The 2011 Tohoku-oki tsunami left a characteristic geochemical signature in the sediments of the Misawa harbor on the Aomori coastline (northern Japan), not only in vertical... 相似文献
13.
Piero Bellanova Mike Frenken Bruce Richmond Jan Schwarzbauer Seanpaul La Selle Frances Griswold Bruce Jaffe Alan Nelson Klaus Reicherter 《Sedimentology》2020,67(3):1230-1248
Far-field tsunami deposits observed in the Kahana Valley, O‘ahu, Hawai‘i (USA), were investigated for their organic-geochemical content. During short high-energy events, (tsunamis and storms) organic and chemical components are transported with sediment from marine to terrestrial areas. This study investigates the use of anthropogenic based organic geochemical compounds (such as polycyclic aromatic hydrocarbons, pesticides and organochlorides) as a means to identify tsunami deposits. Samples were processed by solid–liquid extraction and analyzed using gas chromatography–mass spectrometry. A total of 21 anthropogenic marker compounds were identified, of which 11 compounds were selected for detailed analysis. Although the tsunami deposits pre-date industrial activity in Hawai‘i by several hundred years, distinct changes were found in the concentrations of anthropogenic marker compounds between sandy tsunami deposits and the surrounding mud/peat layers, which may help in identifying tsunami deposits within cores. As expected, low overall concentrations of anthropogenic markers and pollutants were observed due to the lack of industrial input-sources and little anthropogenic environmental impact at the study site. This geochemical characterization of tsunami deposits shows that anthropogenic markers have significant potential as another high-resolution, multi-proxy method for identifying tsunamis in the sedimentary record. 相似文献
14.
Lea Obrocki Andreas Vött Dennis Wilken Peter Fischer Timo Willershäuser Benjamin Koster Franziska Lang Ioannis Papanikolaou Wolfgang Rabbel Klaus Reicherter 《Sedimentology》2020,67(3):1274-1308
The western Peloponnese was repeatedly hit by major tsunami impacts during historical times as reported by historical accounts and recorded in earthquake and tsunami catalogues. Geological signatures of past tsunami impacts have also been found in many coastal geological archives. During the past years, abundant geomorphological and sedimentary evidence of repeated Holocene tsunami landfall was found between Cape Katakolo and the city of Kyparissia. Moreover, neotectonic studies revealed strong crust uplift along regional faults with amounts of uplift between 13 m and 30 m since the mid-Holocene. This study focuses on the potential of direct push in situ sensing techniques to detect tsunami sediments along the Gulf of Kyparissia. Direct push measurements were conducted on the landward shores of the Kaiafa Lagoon and the former Mouria Lagoon from which sedimentary and microfaunal evidence for tsunami landfall are already known. Direct push methods helped to decipher in situ high-resolution stratigraphic records of allochthonous sand sheets that are used to document different kinds of sedimentological and geomorphological characteristics of high-energy inundation, such as abrupt increases in grain size, integration of muddy rip-up clasts and fining upward sequences which are representative of different tsunami inundation pulses. These investigations were completed by sediment coring as a base for local calibration of geophysical direct push parameters. Surface-based electrical resistivity tomography and seismic data with highly resolved vertical direct push datasets and sediment core data were all coupled in order to improve the quality of the geophysical models. Details of this methodological approach, new in palaeotsunami research, are presented and discussed, especially with respect to the question of how the obtained results may help to facilitate tracing tsunami signatures in the sedimentary record and deciphering geomorphological characteristics of past tsunami inundation. Using direct push techniques and based on sedimentary data, sedimentary signatures of two young tsunami impacts that hit the Kaiafa Lagoon were detected. Radiocarbon age control allowed the identification of these tsunami layers as candidates for the ad 551 and ad 1303 earthquake and tsunami events. For these events, there is reliable historical data on major damage on infrastructure in western Greece and on the Peloponnese. At the former Mouria Lagoon, corroborating tsunami traces were found; however, in this case it is difficult to decide whether these signatures were caused by the ad 551 or the ad 1303 event. 相似文献
15.
Landslide hazard and cascading effects following the extreme rainfall event on Madeira Island (February 2010) 总被引：1，自引：1，他引：0
Hieu T. Nguyen Thomas Wiatr T��mas M. Fern��ndez-Steeger Klaus Reicherter Domingos M. M. Rodrigues Rafig Azzam 《Natural Hazards》2013,65(1):635-652
Heavy rainfall on February 20, 2010, triggered numerous shallow rapid landslides across Madeira Island, a Portuguese archipelago in the North Atlantic. Two days after the extreme rainfall event, a field campaign was started which involved describing and mapping a variety of landslide types and the related losses at 120 different locations throughout the Island. Most of the failures started as debris slides or avalanches at high elevations and transformed into debris flows which rushed downslope into populated coastal areas. Over half of the mapped landslides were located in the central and southern area of the island. A further 1,257 landslide locations were revealed in these areas using remote sensing data which were then assembled in a spatial database. Due to anthropogenic influences caused by urban development and population expansion, the event demonstrated the increased vulnerability of the island??s infrastructure. In order to mitigate future losses, it is important to quantify the typical preparatory factors which contribute to rainfall-induced landslides. This increases our understanding of the hazards and associated risks. The analysis shows that based on their spatial frequency, distribution and in the context of the drainage system, three main factors contribute to the triggering of the landslides due to the heavy rainfall event in February 2010: the characteristic soil type, the land cover and the slope gradient. It can now be recognized that the distribution of landslides is highly dependent on the temporal and spatial distribution of these factors. Furthermore, the anthropogenic impact on the extent of the hazard becomes obvious due to poor settlement planning and drainage system modification. 相似文献
16.
Erosion of continental margins in the Western Mediterranean due to sea-level stagnancy during the Messinian Salinity Crisis 总被引：1，自引：1，他引：0
Janna Just Christian H��bscher Christian Betzler Thomas L��dmann Klaus Reicherter 《Geo-Marine Letters》2011,31(1):51-64
High-resolution multi-channel seismic data from continental slopes with minor sediment input off southwest Mallorca Island,
the Bay of Oran (Algeria) and the Alboran Ridge reveal evidence that the Messinian erosional surface is terraced at an almost
constant depth interval between 320 and 380 m below present-day sea level. It is proposed that these several hundred- to 2,000-m-wide
terraces were eroded contemporaneously and essentially at the same depth. Present-day differences in these depths result from
subsidence or uplift in the individual realms. The terraces are thought to have evolved during one or multiple periods of
sea-level stagnancy in the Western Mediterranean Basin. According to several published scenarios, a single or multiple periods
of relative sea-level stillstand occurred during the Messinian desiccation event, generally known as the Messinian Salinity
Crisis. Some authors suggest that the stagnancy started during the refilling phase of the Mediterranean basins. When the rising
sea level reached the height of the Sicily Sill, the water spilled over this swell into the eastern basin. The stagnancy persisted
until sea level in the eastern basin caught up with the western Mediterranean water level. Other authors assigned periods
of sea-level stagnancy to drawdown phases, when inflowing waters from the Atlantic kept the western sea level constant at
the depth of the Sicily Sill. Our findings corroborate all those Messinian sea-level reconstructions, forwarding that a single
or multiple sea-level stagnancies at the depth of the Sicily Sill lasted long enough to significantly erode the upper slope.
Our data also have implications for the ongoing debate of the palaeo-depth of the Sicily Sill. Since the Mallorcan plateau
experienced the least vertical movement, the observed terrace depth of 380 m there is inferred to be close to the Messinian
depth of this swell. 相似文献
17.
18.
High-resolution sea floor imaging (narrow beam sediment profiler) yields evidence for an offshore rupture along a strand of
the Carboneras Fault Zone (CFZ) in the Gulf of Almería off southern Spain. The observed faults affect the seafloor and cut
the Late Holocene sedimentary cover, hence the faults are regarded as active and the escarpments as relatively fresh. Seafloor
faulting is associated with escarpments, fissures, pressure ridges, folds, and reverse faults indicating sinistral strike-slip
faulting with a significant vertical displacement. Adjacent to the major fault zone secondary phenomena such as submarine
slumps and slides are observed. The observed fresh escarpments imply an offshore rupture during a major earthquake along the
CFZ. The southern Iberian margin and the Afro-Eurasian convergence zone form an area of moderate seismicity. However, some
major events occurred, such as the 1522 Almería earthquake (EMS IX; [IGN (2005) Instituto Geografico Nacional, www.ign.es]),
which affected large areas in the western Mediterranean. Different epicentral areas have been suspected, mainly along the
50 km long sinistral CFZ; however, no on-shore surface ruptures and paleoseismological evidences for this event have been
found. Based on our data, a new epicentral area is proposed in the Gulf of Almería precisely along the observed sea floor
rupture area, where the CFZ extend at least for 100 km offshore. Our findings suggest a specific seismic hazards and tsunami
potential for offshore active and seismogenic faults in the Alborán Sea. 相似文献
19.
Paleostress orientations were calculated from fault-slip data of 36 sites located along a traverse through the Central Betic Cordilleras (southern Spain). Heterogeneous fault sets, which are frequent in the area, have been divided into homogeneous subsets by cross-cutting relationships observed in the field and by a paleostress stratigraphy approach applied on each individual fault population. The state of stress was sorted according to main tectonic events and a new chronology is presented of the Miocene to Recent deformation in the central part of the Betic Cordilleras. The deviatoric stress tensors fall into four distinct groups that are regionally consistent and correlate with three Late Oligocene–Aquitanian to Recent major tectonic events in the Betic Cordilleras. The new chronology of the neotectonic evolution includes, from oldest to youngest, the following main tectonic phases:
- (1) Late Oligocene–Aquitanian to Early Tortonian: σ1 subhorizontal N–S, partly E–W directed, σ3 subvertical; compressional structures (thrusting of nappes, large-scale folding) and strike-slip faulting in the Alborán Domain and the External Zone of the Betic Cordilleras;
- (2) Early Tortonian to Pliocene–Pleistocene: σ1 subvertical, σ3 subhorizontal NW–SE, partly N–S directed or E–W-directed (radial extension); large-scale normal faulting in the Central Betic Cordilleras and in the oldest Neogene formations of the Granada Basin related to the gravitational collapse of the Betic Cordilleras and the exhumation of the intensely metamorphosed rock series of the Internal Zones, at the same time formation of the Alborán Basin and intramontane basins such as the Granada Basin;
- (3) Pleistocene to Recent: (3a) σ1 subvertical, σ3 subhorizontal NE–SW with prominent normal faulting, but coevally; (3b) σ1 subhorizontal NW directed, σ3 NE–SW subhorizontal with strike-slip faulting. Extensional structures and strike-slip faulting are related to the ongoing convergence of the Eurasian and African Plates and coeval uplift of the Betic Cordilleras. Reactivation of pre-existing fractures and faults was frequently observed. Phase 3 is interpreted as periodic strike-slip and normal faulting events due to a permutation of the principal stress axes, mainly σ1 and σ2.
Keywords: Neotectonics; Paleostress; Fault-slip data; Deformation history; Betic Cordilleras 相似文献
20.
Reicherter K. R. Jabaloy A. Galindo-Zaldívar J. Ruano P. Becker-Heidmann P. Morales J. Reiss S. González-Lodeiro F. 《International Journal of Earth Sciences》2003,92(6):912-922
One of the most destructive historical earthquakes (M 6.7) in Spain occurred in 1884 along the normal Ventas de Zafarraya Fault located in the Central Betic Cordilleras. Palaeoseismic and radiocarbon data presented in this study are the first to constrain the timing of the pre-1884 fault history in the last 10 ka. These data yield a recurrence interval of between 2 and 3 ka for major earthquakes, under the assumption of uniform return periods along the normal fault. The Holocene slip rate is estimated to be in the order of 0.35±0.05 mm/year, which is significantly higher than the mean slip rate of 0.17±0.03 mm/year since the Tortonian. Several of the most important deformations and secondary features, such as landslides and liquefaction, are related to strong ground motion and document the Holocene activity of the Ventas de Zafarraya Fault. 相似文献