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DEM modelling of the activation and reactivation of capable faults in a typical Apulian rock succession: the viewpoint of local seismic effect during the 1948 Earthquake (Apulia, Italy)

 und   
14. Feb. 2025

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COVER HERUNTERLADEN

Figure 1:

Constitutive elements of a fault zone (from: [10] modified).
Constitutive elements of a fault zone (from: [10] modified).

Figure 2:

Schematic geostructural map of the ‘Candelaro’ fault area (from: [27] modified).
Schematic geostructural map of the ‘Candelaro’ fault area (from: [27] modified).

Figure 3:

Seismicity of the ‘Candelaro’ fault area: a) historical and instrumental seismicity (from: [33, 34] modified) and b) depth and magnitude of earthquakes (from: [39] modified).
Seismicity of the ‘Candelaro’ fault area: a) historical and instrumental seismicity (from: [33, 34] modified) and b) depth and magnitude of earthquakes (from: [39] modified).

Figure 4:

Average input spectra of horizontal and vertical accelerations used for LSR analysis, compared with elastic spectra for rigid substrate of cat. ‘A’ and horizontal topography [52].
Average input spectra of horizontal and vertical accelerations used for LSR analysis, compared with elastic spectra for rigid substrate of cat. ‘A’ and horizontal topography [52].

Figure 5:

Geomechanical model used for numerical simulations.
Geomechanical model used for numerical simulations.

Figure 6:

Models and boundary conditions used in the numerical analyses: a) quasi-static; b) dynamic and LSR (model without pre-existing fault); c) dynamic and LRS (case study with reactivation of a pre-existing normal fault plane 45° dip).
Models and boundary conditions used in the numerical analyses: a) quasi-static; b) dynamic and LSR (model without pre-existing fault); c) dynamic and LRS (case study with reactivation of a pre-existing normal fault plane 45° dip).

Figure 7:

Time histories of the seismic waves input: horizontal ground motion and shear stress (left); vertical ground motion and normal stress (right).
Time histories of the seismic waves input: horizontal ground motion and shear stress (left); vertical ground motion and normal stress (right).

Figure 8:

Displacements, fault core and damage zone extents and plastic states in quasi-static analyses of normal fault generation (left) and reverse fault (right): a–b (dip angle 30°); c–d (dip angle 45°); e–f (dip angle 60°).
Displacements, fault core and damage zone extents and plastic states in quasi-static analyses of normal fault generation (left) and reverse fault (right): a–b (dip angle 30°); c–d (dip angle 45°); e–f (dip angle 60°).

Figure 9:

Dynamic case study analysis of the ‘Candelaro’ active and capable normal fault: a) displacements; b) plastic states.
Dynamic case study analysis of the ‘Candelaro’ active and capable normal fault: a) displacements; b) plastic states.

Figure 10:

Local seismic response (LSR) of the case study: on the left model without a pre-existing fault plane – a) FA in X-acceleration, b) FA in Y-acceleration, c) plastic states; on the right model of the ‘Candelaro’ active and capable normal fault plane – a) FA in X-acceleration, b) FA in Y-acceleration, c) plastic states.
Local seismic response (LSR) of the case study: on the left model without a pre-existing fault plane – a) FA in X-acceleration, b) FA in Y-acceleration, c) plastic states; on the right model of the ‘Candelaro’ active and capable normal fault plane – a) FA in X-acceleration, b) FA in Y-acceleration, c) plastic states.

Quasi-static analyses: failure types, maximum displacement values, extents of fault core and damage zone_

Kinematism Dip angles (degrees) Type of failure Maximum displacement on the ground level (m) Extent of fault core zone on the ground level (m) Extent of the damage zone on the ground level (m)
Normal fault 30 Conjugate failure surfaces 1.49 6.50 9.90
45 Single failure surface 1.83 7.70 9.60
60 Conjugate failure surfaces 2.58 7.80 9.50
Reverse fault 30 Trailing imbricate fan and conjugate surfaces 1.48 26.50 84.50
45 Trailing imbricate fan and conjugate surfaces 1.82 56.10 61.50
60 Conjugate failure surfaces 2.57 20.70 163.20

Values of physical–mechanical parameters of limestone, layer discontinuities and faults (from: [14], [16], [18])_

Physical–mechanical parameters for Mohr–Coulomb elasto-plastic criterion

Lithotype Natural unit weight γa (kN/m3) Friction angle φi (degrees) Cohesion ci (MPa) UCS strength σci (MPa) Tensile strength σti (MPa) Young modulus Ei (GPa) Bulk modulus Ki (GPa) Shear modulus Gi (GPa) Dilation angle (degrees)
Altamura Limestone 24 50 13 69 11 60 33 25 7
Mechanical parameters of discontinuities for Mohr–Coulomb ‘area-contact’ criterion
Rock mass Joint type Joint normal stiffness JKN (GPa/m) Joint shear stiffness JKS (GPa/m) Joint tensile strength Jtens (MPa) Joint friction angle Jfric (degrees) Joint cohesion Jcoh (MPa) Layers dip (degrees) Layers spacing (m) Joint dilation angle (degrees)
Altamura Limestone Layers and faults 249 104 0.70 39 5.29 0 0.80 7

Input parameters for searching accelerograms in the seismological European Strong-motion database_

Acceleration component Magnitude range Epicentral distance range (km) Site class Topographic class Nominal life (years) Usage class Limit state Scaled records
Horizontal 5.6–7 0–20 A T1 50 II SLV No
Vertical 5.2–7 0–30 A T1 50 II SLV Yes

Dynamic case study analysis of the ‘Candelaro’ active and capable normal fault: failure type, displacement values, extents of fault core and damage zone_

Kinematism Dip angles (degrees) Type of failure Displacement in depth along the fault plane UDEC simulation (m) Displacement on the ground level UDEC simulation (m) Displacement on the ground level equation [2] (m) Displacement along the fault plane - Hanks and Kanamori’s equation (m)
Normal fault 45 Conjugate surfaces ‘Graben o flower structure’ 0.80–1.30 0.1–0.2 0.12 0.92

Minimum, maximum and residual values of calcarenite physical–mechanical parameters (from: [5], [15], [17], [23], [26], [59])_

Physical–mechanical parameters for Mohr–Coulomb Strain-Softening criterion

Lithotype Natural unit weight γa (kN/m3) Porosity nmin - nmax (%) Imbibition coefficient Cimin - Cimax (%) Friction angle φres - φmax (degrees) Cohesion cres - cmax (MPa) UCS strength σcmax (MPa) Tensile strength σtres - σtmax (MPa) Young modulus Emax (GPa) Bulk modulus Kmax (GPa) Shear modulus Gmax (GPa) Dilation angle Δres - Δmax (degrees)
Gravina Calcarenite 19 35 – 50 15 – 40 30 – 38 0.13 – 0.29 2.0 0.11 – 0.26 3.5 2.9 1.3 3 – 5
Sprache:
Englisch
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Fachgebiete der Zeitschrift:
Geowissenschaften, Geowissenschaften, andere, Materialwissenschaft, Verbundwerkstoffe, Poröse Materialien, Physik, Mechanik und Fluiddynamik