scholarly journals Fossil landscapes and youthful seismogenic sources in the central Apennines: excerpts from the 24 August 2016, Amatrice earthquake and seismic hazard implications

2016 ◽  
Vol 59 ◽  
Author(s):  
Gianluca Valensise ◽  
Paola Vannoli ◽  
Roberto Basili ◽  
Lorenzo Bonini ◽  
Pierfrancesco Burrato ◽  
...  
Keyword(s):  
Seismic Hazard ◽  
Active Faults ◽  
Upper Crust ◽  
Central Apennines ◽  
Great Caution ◽  
Seismogenic Sources ◽  
Seismogenic Faults ◽  
2016 Amatrice Earthquake

<p><em>We show and discuss the similarities among the 2016 Amatrice (Mw 6.0), 1997 Colfiorito-Sellano (Mw 6.0-5.6) and 2009 L’Aquila (Mw 6.3) earthquakes. They all occurred along the crest of the central Apennines and were caused by shallow dipping faults between 3 and 10 km depth, as shown by their characteristic InSAR signature. We contend that these earthquakes delineate a seismogenic style that is characteristic of this portion of the central Apennines, where the upward propagation of seismogenic faults is hindered by the presence of pre-existing regional thrusts. This leads to an effective decoupling between the deeper seismogenic portion of the upper crust and its uppermost 3 km.The decoupling implies that active faults mapped at the surface do not connect with the seismogenic sources, and that their evolution may be controlled by passive readjustments to coseismic strains or even by purely gravitational motions. Seismic hazard analyses and estimates based on such faults should hence be considered with great caution as they may be all but representative of the true seismogenic potential.</em></p><em></em>

A new 3D velocity model of Central Apennines: insights from 2D/3D geological modelling and earthquake relocation.

2021 ◽  
Author(s):  
Andrea D'Ambrosio ◽  
Eugenio Carminati ◽  
Carlo Doglioni ◽  
Lorenzo Lipparini ◽  
Mario Anselmi ◽  
...  
Keyword(s):  
Seismic Hazard ◽  
Cross Sections ◽  
3D Model ◽  
Velocity Model ◽  
Earthquake Relocation ◽  
Central Apennines ◽  
Seismic Stations ◽  
Velocity Models ◽  
3D Velocity Model ◽  
Seismogenic Faults

&lt;p&gt;The Central Apennines fold-and-thrust belt (Central Italy) is characterized by the presence of several active faults, potentially capable of generating damaging earthquakes. To support seismic hazard studies over the area, a new 3D velocity model was built, integrating a wide range of surface and subsurface data.&lt;/p&gt;&lt;p&gt;The tectonic framework of the area (from Sulmona plain to Maiella Mt), is still debated in literature, also due to the lack of both an adequate geophysical data set and a reliable velocity model at the crustal scale.&lt;/p&gt;&lt;p&gt;In addition, the low number of seismic stations available for the acquisition of Vp/Vs arrival times, and the very low seismicity detected in the study area (the Sulmona and Caramanico Apennine valleys are considered as &amp;#8220;seismic gaps&amp;#8221;), lead to a difficult interpretation of the subsurface tectonic structures.&lt;/p&gt;&lt;p&gt;3D velocity modelling could well represent an important tool to support these deep crustal reconstructions as well earthquake relocation studies and could enhance the definition of seismogenic faults deep geometries, hence supporting a better risk assessment over the area of these potential locked faults.&lt;/p&gt;&lt;p&gt;Using the knowledge developed within the oil&amp;gas industry as well in gas/CO&lt;sub&gt;2&lt;/sub&gt; storage projects for the construction of 3D velocity models, extensively used to obtain subsurface imaging and define the geometry of the reservoirs and traps in the depth domain, a similar methodological approach was implemented over the study area.&lt;/p&gt;&lt;p&gt;The subsurface dataset was partially inherited by the past hydrocarbon exploration activities (e.g. seismic lines, exploration wells and sonic logs) and by the literature (e.g. time/depth regional models). Tomographic sections and relocated earthquake hypocentres were also integrated form geophysical studies. Geological maps (1:50.000 &amp; 1:100.000 scale) represent the surface dataset that we used to create the surface interpretation of the regional geology.&lt;/p&gt;&lt;p&gt;As a first step, 18 2D balanced regional geological cross-sections, dip-oriented (W-E) across the Central Apennine, were built define the structural picture at regional scale. The cross-sections were built using MOVE (Petroleum Experts) and Petrel (Schlumberger) software. The following modelling step was the 3D model construction, in which the surface/subsurface data as well as all the geological sections were integrated in the final 3D structural and geological model.&lt;/p&gt;&lt;p&gt;The main geological layers reconstructed in the 3D model were than populated using the appropriated interval velocity values, building the final 3D velocity model in which the lateral velocity variation due to the presence of different facies/geological domains were considered.&lt;/p&gt;&lt;p&gt;As one of the results, we defined several 1D-velocity models coherent with the regional 3D velocity model, in which the key seismic stations and the earthquakes hypocentres dataset for the most potential seismogenic faults were included. 1D models were characterized by different degree of simplification, in order to test diverse approaches for the earthquake relocation. For this exercise, we used public dataset extracted by the analysis of microseismicity of the Sulmona basin.&lt;/p&gt;&lt;p&gt;We believe that the proposed approach can represents an effective method for combining geological and geophysical data to improve the subsurface and seismogenic faults interpretation, contributing to the seismic hazard assessment.&lt;/p&gt;

Towards a comprehensive European fault database for induced seismic hazard research

2020 ◽  
Author(s):  
Serge Van Gessel ◽  
Harry Middelburg ◽  
Esther Hintersberger ◽  
Tine Larsen ◽  
Sabrine Ben Rhouma ◽  
...  
Keyword(s):  
Stress State ◽  
Seismic Hazard ◽  
Anthropogenic Activities ◽  
Active Faults ◽  
The European Union ◽  
Fault Systems ◽  
Geological Conditions ◽  
Seismogenic Faults ◽  
And Behavior

&lt;p&gt;&lt;strong&gt;Towards a comprehensive European fault database for induced seismic hazard research&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;Seismogenic faults and fault systems in tectonically active regions are extensively studied as a source of seismic hazard and especially of high magnitude natural earthquakes. Global research has already resulted in several databases and models presenting location, characteristics and kinematic behavior of such faults (e.g. GEM Global Active Faults Database, SHARE European Database of Seismogenic Faults, USGS Quaternary faults database).&lt;/p&gt;&lt;p&gt;Faults that are inactive under present-day geological conditions are far more abundant, yet less-well documented. Nevertheless, these faults can potentially pose significant hazards under anthropogenic activities, particularly when the stress state of such faults is influenced by adjacent active fault systems (e.g. Northern Italy). Subsurface extraction and injection of fluids can either alter the in-situ stress state to a level exceeding the critical stress threshold (e.g. through pressure-induced compaction) or reduce the fault strength to a point where natural stresses can trigger fault movements (e.g. through the invasion of fluids into the fault zone). Well-known cases are reported among others in Basel &amp;#8211; Switzerland (geothermal stimulation), Oklahoma &amp;#8211; US (waste water injection) and Groningen &amp;#8211; The Netherlands (conventional hydrocarbon extraction).&lt;/p&gt;&lt;p&gt;Here, we present the development of a pan-European fault database by the project GeoERA-HIKE. The database incorporates the locations, geometries, characteristics and scientific references of both active and inactive faults and fault systems and will be complementary to existing databases of seismogenic faults. The database information is derived from national mapping studies and local assessments by the European Geological Survey Organizations and includes, amongst others, surface outcrop observations, geophysical monitoring, boreholes and geological modelling studies.&lt;/p&gt;&lt;p&gt;The primary goal of the database is to support induced hazard studies with better access to harmonized data and knowledge on fault characteristics and behavior. The correlation of fault systems across Europe with a generic semantic concepts framework provides better insight into the genetic links between active and inactive fault systems within the greater structural geological development of Europe. The integration of data from different geoscience disciplines will improve the understanding of in-situ characteristics and behavior. Ultimately, the database is intended to become a collaborative tool for future fault characterization and research by geoscience institutes.&lt;/p&gt;&lt;p&gt;The GeoERA-HIKE project has received funding from the European Union&amp;#8217;s Horizon 2020 research and innovation programme under agreement No. 731166&lt;/p&gt;

scholarly journals Geologic and geodetic constraints on the seismic hazard of Malawi’s active faults: The Malawi Seismogenic Source Database (MSSD)

2021 ◽  
Author(s):  
Jack N. Williams ◽  
Luke N. J. Wedmore ◽  
Åke Fagereng ◽  
Maximilian J. Werner ◽  
Hassan Mdala ◽  
...  
Keyword(s):  
Seismic Hazard ◽  
Active Fault ◽  
Active Faults ◽  
Slip Rate ◽  
Slip Rates ◽  
Source Database ◽  
Seismogenic Sources ◽  
Seismogenic Source ◽  
Recurrence Intervals ◽  
Seismic Reflector

Abstract. Active fault data are commonly used in seismic hazard assessments, but there are challenges in deriving the slip rate, geometry, and frequency of earthquakes along active faults. Herein, we present the open-access geospatial Malawi Seismogenic Source Database (MSSD), which describes the seismogenic properties of faults that have formed during East African rifting in Malawi. We first use empirical observations to geometrically classify active faults into section, fault, and multi-fault seismogenic sources. For sources in the North Basin of Lake Malawi, slip rates can be derived from the vertical offset of a seismic reflector that is estimated to be 75 ka based on dated core. Elsewhere, slip rates are constrained from advancing a ‘systems-based’ approach that partitions geodetically-derived rift extension rates in Malawi between seismogenic sources using a priori constraints on regional strain distribution in magma-poor continental rifts. Slip rates are then combined with source geometry and empirical scaling relationships to estimate earthquake magnitudes and recurrence intervals, and their uncertainty is described from the variability of outcomes from a logic tree used in these calculations. We find that for sources in the Lake Malawi’s North Basin, where slip rates can be derived from both the geodetic data and the offset seismic reflector, the slip rate estimates are within error of each other, although those from the offset reflector are higher. Sources in the MSSD are 5–200 km long, which implies that large magnitude (MW 7–8) earthquakes may occur in Malawi. Low slip rates (0.05–2 mm/yr), however, mean that the frequency of such events will be low (recurrence intervals ~103–104 years). The MSSD represents an important resource for investigating Malawi’s increasing seismic risks and provides a framework for incorporating active fault data into seismic hazard assessment in other tectonically active regions.

scholarly journals THE GREEK CATALOGUE OF ACTIVE FAULTS AND DATABASE OF SEISMOGENIC SOURCES

2017 ◽  
Vol 43 (1) ◽  
pp. 486 ◽  
Author(s):  
S. Pavlides ◽  
R. Caputo ◽  
S. Sboras ◽  
A. Chatzipetros ◽  
G. Papathanasiou ◽  
...  
Keyword(s):  
Seismic Hazard ◽  
Active Faults ◽  
Geophysical Data ◽  
Aegean Area ◽  
Aegean Region ◽  
Seismogenic Sources ◽  
Available Information ◽  
Different Sources ◽  
Systematic Collection ◽  
Of Greece

The new reasearch project to create the Greek Catalogue of Active Faults and Database of Seismogenic Sources has three major goals: (i) the systematic collection of all available information concerning neotectonic, active and capable faults as well as broader seismogenic volumes within the Aegean Region; the search will be mainly based on geological and geophysical data; (ii) the quantification of the principal seismotectonic parameters of the different sources and the associated degree of uncertainty; (iii) to supply an integrated view of potentially damaging seismogenic sources for a better assessment of the Seismic Hazard of Greece. The informatic framework of the database follows that used for the Italian Database of Individual Seismogenic Sources (DISS). In this paper we present the architecture of the new Database of Active faults of the broader Aegean Area relative to Greece, the progress made up to present and the following activities yet to be accomplished.

Effect of Time Dependence on Probabilistic Seismic-Hazard Maps and Deaggregation for the Central Apennines, Italy

2009 ◽  
Vol 99 (2A) ◽  
pp. 585-610 ◽  
Author(s):  
A. Akinci ◽  
F. Galadini ◽  
D. Pantosti ◽  
M. Petersen ◽  
L. Malagnini ◽  
...  
Keyword(s):  
Seismic Hazard ◽  
Time Dependence ◽  
Probabilistic Seismic Hazard ◽  
Hazard Maps ◽  
Central Apennines ◽  
Seismic Hazard Maps

scholarly journals Active Fault Systems in the Inner Northwest Apennines, Italy: A Reappraisal One Century after the 1920 Mw ~6.5 Fivizzano Earthquake

Geosciences ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 139
Author(s):  
Giancarlo Molli ◽  
Isabelle Manighetti ◽  
Rick Bennett ◽  
Jacques Malavieille ◽  
Enrico Serpelloni ◽  
...  
Keyword(s):  
Large Scale ◽  
Active Fault ◽  
Active Faults ◽  
Dense Network ◽  
Earthquake Fault ◽  
Slip Rates ◽  
Fault Systems ◽  
Seismological Data ◽  
Seismogenic Faults

Based on the review of the available stratigraphic, tectonic, morphological, geodetic, and seismological data, along with new structural observations, we present a reappraisal of the potential seismogenic faults and fault systems in the inner northwest Apennines, Italy, which was the site, one century ago, of the devastating Mw ~6.5, 1920 Fivizzano earthquake. Our updated fault catalog provides the fault locations, as well as the description of their architecture, large-scale segmentation, cumulative displacements, evidence for recent to present activity, and long-term slip rates. Our work documents that a dense network of active faults, and thus potential earthquake fault sources, exists in the region. We discuss the seismogenic potential of these faults, and propose a general tectonic scenario that might account for their development.

scholarly journals Bayesian probabilities for occurrence of large earthquakes in the seismogenic sources of Japan and Phillipine during the period 1998-2017

2001 ◽  
Vol 34 (4) ◽  
pp. 1619
Author(s):  
T. M. TSAPANOS ◽  
O. CH. GALANIS ◽  
S. D. MAVRIDOU ◽  
M. P. HELMl
Keyword(s):  
Seismic Hazard ◽  
Bayesian Statistics ◽  
Poisson Distribution ◽  
Bayesian Approach ◽  
Seismic Sources ◽  
Time Interval ◽  
Seismogenic Sources ◽  
The One ◽  
Large Earthquakes ◽  
The Bayesian Approach

The Bayesian statistics is adopted in 11 seismic sources of Japan and 14 of Philippine in order to estimate the probabilities of occurrence of large future earthquakes, assuming that earthquakes occurrence follows the Poisson distribution. The Bayesian approach applied represents the probability that a certain cut-off magnitude (or larger) will exceed in a given time interval of 20 years, that is 1998-2017. This cut-off magnitude is chosen the one with M=7.0 or greater. In this case we can consider these obtained probabilities as a seismic hazard presentation. More over curves are produced which present the fluctuation of the seismic hazard between these seismic sources. These graphs of varying probability are useful either for engineering or other practical purposes

scholarly journals Tectonic Geomorphology and Paleoseismology of the Sharkhai fault: a new source of seismic hazard for Ulaanbaatar (Mongolia)

2021 ◽  
Author(s):  
Abeer Al-Ashkar ◽  
Antoine Schlupp ◽  
Matthieu Ferry ◽  
Ulziibat Munkhuu
Keyword(s):  
Seismic Hazard ◽  
Scaling Laws ◽  
Active Faults ◽  
Seismic Hazard Assessment ◽  
Capital City ◽  
Tectonic Geomorphology ◽  
Time Interval ◽  
Coseismic Slip ◽  
Slip Rates ◽  
Large Earthquakes

Abstract. We present new constraints from tectonic geomorphology and paleoseismology along the newly discovered Sharkhai fault near the capital city of Mongolia. Detailed observations from high resolution Pleiades satellite images and field investigations allowed us to map the fault in detail, describe its geometry and segmentation, characterize its kinematics, and document its recent activity and seismic behavior (cumulative displacements and paleoseismicity). The Sharkhai fault displays a surface length of ~40 km with a slightly arcuate geometry, and a strike ranging from N42° E to N72° E. It affects numerous drainages that show left-lateral cumulative displacements reaching 57 m. Paleoseismic investigations document the faulting and deposition record for the last ~3000 yr and reveal that the penultimate earthquake (PE) occurred between 1515 ± 90 BC and 945 ± 110 BC and the most recent event (MRE) occurred after 860 ± 85 AD. The resulting time interval of 2080 ± 470 years is the first constraint on the Sharkhai fault for large earthquakes. On the basis of our mapping of the surface rupture and the resulting segmentation analysis, we propose two possible scenarios for large earthquakes with likely magnitudes between 6.4 ± 0.2 and 7.1 ± 0.2. Furthermore, we apply scaling laws to infer coseismic slip values and derive preliminary estimates of long-term slip rates between 0.2 ± 0.2 and 1.0 ± 0.5 mm/y. Finally, we propose that these original observations and results from a newly discovered fault should be taken into account for the seismic hazard assessment for the city of Ulaanbaatar and help build a comprehensive model of active faults in that region.

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