Crustal deformation in the northern Andes – A new GPS velocity field

2019 ◽  
Vol 89 ◽  
pp. 76-91 ◽  
Author(s):  
Héctor Mora-Páez ◽  
James N. Kellogg ◽  
Jeffrey T. Freymueller ◽  
Dave Mencin ◽  
Rui M.S. Fernandes ◽  
...  
2021 ◽  
Vol 873 (1) ◽  
pp. 012089
Author(s):  
Suchi Rahmadani ◽  
Irwan Meilano ◽  
Dina A. Sarsito ◽  
Susilo

Abstract Eastern Indonesia lies in a complex tectonic region due to the interaction of four major tectonic plates: the Australian Plate, Pacific Plate, Philippine Sea Plate, and Sunda Block. Therefore, this region hosted some destructive seismic activities as well as tectonic deformation, such as the Mw 7.5 Palu Earthquake, the sequences of the 2018 Lombok Earthquake, and the Mw 6.5 Ambon Earthquake in 2019. Our work proposes a recent study on crustal deformation in Eastern Indonesia inferred from Global Positioning System (GPS) velocity field. We used GPS data from the observations of 49 permanent and 61 campaign stations from 2010 to 2018. Here, our velocity field result represents long-term tectonic deformation regions in Eastern Indonesia continuously, from Bali in the west to Papua in the east, demonstrated both in the ITRF 2008 and the Sunda reference frames. The spatial pattern of velocity field map collected from this research will give an initial insight into the present-day tectonic condition in Eastern Indonesia and then can be used to improve our ability to assess this area’s earthquake potential.


Geosphere ◽  
2020 ◽  
Author(s):  
Katherine A. Guns ◽  
Richard A Bennett ◽  
Joshua C. Spinler ◽  
Sally F. McGill

Assessing fault-slip rates in diffuse plate boundary systems such as the San Andreas fault in southern California is critical both to characterize seis­mic hazards and to understand how different fault strands work together to accommodate plate boundary motion. In places such as San Gorgonio Pass, the geometric complexity of numerous fault strands interacting in a small area adds an extra obstacle to understanding the rupture potential and behavior of each individual fault. To better understand partitioning of fault-slip rates in this region, we build a new set of elastic fault-block models that test 16 different model fault geometries for the area. These models build on previ­ous studies by incorporating updated campaign GPS measurements from the San Bernardino Mountains and Eastern Transverse Ranges into a newly calculated GPS velocity field that has been removed of long- and short-term postseismic displacements from 12 past large-magnitude earthquakes to estimate model fault-slip rates. Using this postseismic-reduced GPS velocity field produces a best- fitting model geometry that resolves the long-standing geologic-geodetic slip-rate discrepancy in the Eastern California shear zone when off-fault deformation is taken into account, yielding a summed slip rate of 7.2 ± 2.8 mm/yr. Our models indicate that two active strands of the San Andreas system in San Gorgonio Pass are needed to produce sufficiently low geodetic dextral slip rates to match geologic observations. Lastly, results suggest that postseismic deformation may have more of a role to play in affecting the loading of faults in southern California than previously thought.


2014 ◽  
Vol 119 (8) ◽  
pp. 6613-6629 ◽  
Author(s):  
Halfdan Pascal Kierulf ◽  
Holger Steffen ◽  
Matthew James Ross Simpson ◽  
Martin Lidberg ◽  
Patrick Wu ◽  
...  

Tectonics ◽  
2010 ◽  
Vol 29 (6) ◽  
pp. n/a-n/a ◽  
Author(s):  
Alexander V. Zubovich ◽  
Xiao-qiang Wang ◽  
Yuri G. Scherba ◽  
Gennady G. Schelochkov ◽  
Robert Reilinger ◽  
...  

Solid Earth ◽  
2016 ◽  
Vol 7 (5) ◽  
pp. 1349-1363 ◽  
Author(s):  
Hai Ninh Nguyen ◽  
Philippe Vernant ◽  
Stephane Mazzotti ◽  
Giorgi Khazaradze ◽  
Eva Asensio

Abstract. We present a new 3-D GPS velocity solution for 182 sites for the region encompassing the Western Alps, Pyrenees, and southern France. The velocity field is based on a Precise Point Positioning (PPP) solution, to which we apply a common-mode filter, defined by the 26 longest time series, in order to correct for network-wide biases (reference frame, unmodeled large-scale processes, etc.). We show that processing parameters, such as troposphere delay modeling, can lead to systematic velocity variations of 0.1–0.5 mm yr−1 affecting both accuracy and precision, especially for short (< 5 years) time series. A velocity convergence analysis shows that minimum time-series lengths of  ∼  3 and  ∼  5.5 years are required to reach a velocity stability of 0.5 mm yr−1 in the horizontal and vertical components, respectively. On average, horizontal residual velocities show a stability of  ∼  0.2 mm yr−1 in the Western Alps, Pyrenees, and southern France. The only significant horizontal strain rate signal is in the western Pyrenees with up to 4  ×  10−9 yr−1 NNE–SSW extension, whereas no significant strain rates are detected in the Western Alps (< 1  ×  10−9 yr−1). In contrast, we identify significant uplift rates up to 2 mm yr−1 in the Western Alps but not in the Pyrenees (0.1 ± 0.2 mm yr−1). A correlation between site elevations and fast uplift rates in the northern part of the Western Alps, in the region of the Würmian ice cap, suggests that part of this uplift is induced by postglacial rebound. The very slow uplift rates in the southern Western Alps and in the Pyrenees could be accounted for by erosion-induced rebound.


2002 ◽  
Vol 359 (1-2) ◽  
pp. 29-46 ◽  
Author(s):  
Changyuan Qin ◽  
Constantinos Papazachos ◽  
Eleftheria Papadimitriou

2019 ◽  
Vol 13 (4) ◽  
pp. 305-316 ◽  
Author(s):  
M. Foumelis

Abstract The broader area of Athens, a region exhibiting relatively low crustal deformation, was stroke in 1999 by a catastrophic earthquake posing serious questions regarding strain accumulation in slow deforming regions located within active geodynamic regimes. In the present study, the establishment of a dense geodetic network, primarily designed to monitor local tectonic movements is reported. A comprehensive GNSS velocity field, over the period 2005–2008, as well as calculated geodetic strain rates is presented. It is shown that a single strain tensor is insufficient to express the heterogeneity of the local geodetic field. Local variability of strain is successfully depicted, indicating the western part of Athens as the area of higher strain accumulation. Maximum dilatation rates occur along a NNE-SSW direction between Parnitha Mt. and Thriasio basin. The observed dilatation can be associated to WNW-ESE trending active fault zones, which appear to abruptly terminate towards East along a major NNE-SSW Miocene tectonic boundary. These findings are consistent to the stress field responsible for the Athens 1999 earthquake, also in agreement with geological and tectonic observations. Finally, the implications of the observed motion field on the understanding of the kinematics and dynamics of the region as well as the role of inherited inactive tectonic structures are discussed.


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