scholarly journals Constraints on upper plate deformation in the Nicaraguan subduction zone from earthquake relocation and directivity analysis

2010 ◽  
Vol 11 (3) ◽  
pp. n/a-n/a ◽  
Author(s):  
S. W. French ◽  
L. M. Warren ◽  
K. M. Fischer ◽  
G. A. Abers ◽  
W. Strauch ◽  
...  
Keyword(s):  
Subduction Zone ◽  
Earthquake Relocation ◽  
Plate Deformation

scholarly journals FAULTING DEFORMATION OF THE MESOHELLENIC TROUGH IN THE KASTORIA-NESTORION REGION (WESTERN MACEDONIA, GREECE)

2017 ◽  
Vol 43 (1) ◽  
pp. 495
Author(s):  
M. D Tranos ◽  
D.M. Mountrakis ◽  
C. B Papazachos ◽  
E. Karagianni ◽  
D. Vamvakaris
Keyword(s):  
Subduction Zone ◽  
Satellite Images ◽  
Fault Slip ◽  
Stress Inversion ◽  
Active Deformation ◽  
Hellenic Subduction Zone ◽  
Plate Deformation ◽  
Late Tertiary ◽  
Inversion Analysis ◽  
Geometry And Kinematics

The Kastoria-Nestorion region, which belongs to the Tertiary MesoHellenic Trough (MHT), is a low relief NW-SE trending intermountainous basin filled with Tertiary molasse-type sedimentary rocks and nowadays drained by the Aliakmnonas River and its tributaries. In the present work, the large fault zones in the region and the general fault pattern are defined, mapped and described with the aid of satellite images. In addition, a large number of fault-slip data from the mesoscale exposed faults has been recorded, in order to better understand the faulting geometry and kinematics of the region. The stress-inversion analysis of these fault-slip data in comparison with earthquake faultplane solution information permits us to define the stress regimes imposed to the region from the Late Tertiary up to the present and to correlate them with the late orogenic and post-orogenic deformation of the Hellenic orogen. In particular, five stress regimes have been defined from which the former two (D1 and D2) are related to the late collisional processes between the Apulia and Eurasia plates, the next two events (D3 and D4) are related to the present-day Hellenic subduction zone, whereas the last D5 event which is the active deformation of the region appears as an intra-continental or intra-plate deformation more related with the Adria-Eurasia ongoing convergence rather with the Hellenic subduction zone.

Evidence of subduction zone segmentation: Finite-difference tomography and earthquake relocation along the Java margin

2020 ◽  
Author(s):  
Anne Sirait ◽  
Anne Meltzer ◽  
Joshua Stachnik ◽  
Mohamad Ramdhan ◽  
Nova Heryandoko
Keyword(s):  
Finite Difference ◽  
Subduction Zone ◽  
Earthquake Relocation

scholarly journals Upper-plate deformation of Late Pleistocene marine terraces in the Trinidad, California, coastal area, southern Cascadia subduction zone

Geosphere ◽  
2019 ◽  
Vol 15 (4) ◽  
pp. 1323-1341 ◽  
Author(s):  
J. Scott Padgett ◽  
Harvey M. Kelsey ◽  
David Lamphear
Keyword(s):  
Subduction Zone ◽  
Sea Level ◽  
Coastal Area ◽  
Hanging Wall ◽  
Cascadia Subduction Zone ◽  
Marine Terrace ◽  
Plate Deformation ◽  
Marine Terraces ◽  
Sea Cliff

Abstract Forming at sea level, uplifted shore platforms serve as long-term geodetic markers. The spatial distribution and elevation of marine terrace sequences offer insight into regional tectonics. In the Trinidad coastal area (California, USA), active tectonic processes reflect upper-plate deformation above the southern extent of the Cascadia subduction megathrust. A set of five uplifted and deformed Late Pleistocene marine terraces is preserved in the Trinidad region and provides an opportunity to analyze regional uplift, folding, and faulting. Using lidar imagery embedded within a GIS, we employ a surface classification model (SCM) that identifies uplifted marine terraces on the basis of their micro-topographical characteristics, i.e., low slope and low roughness. The SCM-based identification of marine terraces both supplements and verifies existing field mapping. We demonstrate the utility of the SCM, which can be applied to a variety of surface terrain analysis investigations that seek to identify smooth and/or rough terrain features, e.g., terraces and fault scarps. Age assignments for the five marine terraces, which range from 80 ka to <500 ka, are based on paleo–sea cliff geomorphology and soil development trends. Specifically, the steepest, highest, and most prominent paleo–sea cliff, which is associated with terrace number 3, is correlated to the long-duration sea-level highstand centered at 125 ka (marine isotope stage 5e), exemplifying a novel method in relative age assignment for Pleistocene geomorphic features. Based on these age assignments, the average maximum uplift rates in the Trinidad coastal area are ∼1.0 m/k.y., and the average long-term uplift rate diminishes westward to ∼0.4 – 0.5 m/k.y. on the downthrown side of the Trinidad fault. Based on analysis of deformation using the high-resolution lidar imagery of the marine terraces, the Trinidad hanging-wall anticline represents a fault propagation fold that ceased to be active when the associated reverse fault, the Trinidad fault, daylighted to the surface ca. 80–100 ka. Based on deformation tilts of a marine terrace with an assigned age of 200 ka, the Trinidad anticline has accommodated at least 1 km of shortening in the last 200 k.y., which represents at least 2% of the convergence of the Juan de Fuca plate relative to North America over the same time period. Overall, both the hanging wall and the footwall of the Trinidad fault show long-term positive rock uplift, which implies that the Trinidad anticline and fault are contained within the hanging wall of a deeper structure. Therefore, the Trinidad fault likely splays off of the Cascadia subduction zone megathrust or off of a deeper thrust fault that splays off of the megathrust.

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