Rigid and non-rigid micro-plates: Philippines and Myanmar-Andaman case studies

Rangin, Claude

doi:10.1016/j.crte.2015.10.008

Cited by 14 publications

(7 citation statements)

References 27 publications

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“…Our analysis of the structure of the Lau Basin, incorporating all of the classified CMT data, the mapped lineaments, and the current understanding of plate boundaries and microplate dynamics, is summarized as a schematic model of deformation in Figure 13. The data agree well with global stress maps of this region that show the majority of the deformation in the back-arc is strike-slip (Heidbach et al, 2018), but also support more focused studies (Bonnardot et al, 2007;Conder & Wiens, 2011;Crawford et al, 2003;Sleeper & Martinez, 2014, 2016Zellmer & Taylor, 2001), which highlight the complexity of the stress regimes in the Lau Basin. In particular, different types of faulting that were not previously classified inform the styles of plate deformation and the emergence of new plate boundary segments and microplates (discussed further below).…”

Section: Discussionsupporting

confidence: 84%

“…Back‐arc basins behind curved trenches are subject to both rigid and nonrigid deformation and are inherently unstable. Nonrigid deformation manifests as transform zones at overlapping spreading centers (Hey et al, 1986) and internal deformation or buckling (Gordon et al, 1998; Rangin, 2016), with strongly partitioned seismicity (Engeln & Stein, 1984; Hey et al, 1986). The kinematics of both nonrigid and rigid deformation also has significant implications for the distribution of magmatic and hydrothermal systems, as new crustal‐scale faults (e.g., microplate boundaries) provide pathways for melts and fluids to reach the surface (Hannington et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

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Shallow Seismicity and the Classification of Structures in the Lau Back‐Arc Basin

Baxter

Hannington

Stewart

et al. 2020

Geochem Geophys Geosyst

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 Centroid Moment Tensors, calculated for large, shallow seismic events were compared to seafloor lineaments mapped throughout the Lau Basin.  The most likely fault plane solutions were chosen, thus classifying the faults and establishing the nature of the basin's stress regimes.  Stress regimes are highly variable, but dominated by both rigid and non-rigid transcurrent deformation, and extension at spreading centers.

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Section: Discussionsupporting

confidence: 84%

Section: Introductionmentioning

confidence: 99%

Shallow Seismicity and the Classification of Structures in the Lau Back‐Arc Basin

Baxter

Hannington

Stewart

et al. 2020

Geochem Geophys Geosyst

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“…All the analyses were carried out using 3DStress® version 5 software developed by the Southwest Research Institute. Present-day principal stress directions applied were based on the regional GPS studies of Negros Island (i.e., [34,38]). Stress magnitudes were estimated from the lithological overburden pressure (for the vertical stress, S v ), borehole leak-off tests (for the minimum horizontal stress, S Hmin ), and the derived shape ratios from the palaeostress analysis (which allows calculation of the maximum horizontal stress, S Hmax ).…”

Section: Slip and Dilation Tendency Analysismentioning

confidence: 99%

Tectonic Evolution of the Southern Negros Geothermal Field and Implications for the Development of Fractured Geothermal Systems

et al. 2018

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Fluid flow pathway characterisation is critical to geothermal exploration and exploitation. In fractured geothermal reservoirs, it requires a good understanding of the structural evolution together with the fracture distribution and fluid flow properties. A fieldwork-based approach has been used to evaluate the potential fracture permeability characteristics of a typical high-temperature geothermal reservoir in the Southern Negros Geothermal Field, Philippines. This is a liquid-dominated resource hosted in the andesitic Quaternary Cuernos de Negros Volcano, Negros Island. Fieldwork reveals two main fracture groups based on fault rock characteristics, alteration type, relative age of deformation, and associated thermal manifestation, with the youngest fractures mainly related to the development of the current geothermal system. Fault kinematics, cross-cutting relationships, and palaeostress analysis suggest at least two distinct deformation events under changing stress fields since probably the Pliocene. We propose that this deformation history was influenced by the development of the Cuernos de Negros Volcano and the northward propagation of a major neotectonic structure located to the northwest, the Yupisan Fault. A combined slip and dilation tendency analysis of the mapped faults indicates that NW-SE structures should be particularly promising drilling targets under the inferred current stress regime, consistent with drilling results. However, existing boreholes also suggest that NE–SW structures can act as effective channels for geothermal fluids. Our observations suggest that these features were initiated as the dominant features in the older kinematic system and have then been reactivated at the present day.

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“…The present stress regime of Negros is characterized by a general WNW-ESE to NW-SE-oriented horizontal compression (Lin and Lo, 2013;Rangin 2016;Rangin et al 1999) consistent with the tectonic setting of the Philippine archipelago. The last destructive earthquake on Negros Island was a Mw6.7 in February 2012 located in the central coast area (USGS 2012), generated by the NNE-SSWtrending NW-dipping Yupisan Fault (Aurelio et al 2017;Figure 1a).…”

Section: Geology Of the Areamentioning

confidence: 68%

Fracture attribute and topology characteristics of a geothermal reservoir: Southern Negros, Philippines

Primaleon

McCaffrey

Holdsworth

2020

JGS

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The characterization of fracture networks using attribute and topological analyses has not been widely applied to the understanding and prediction of the secondary porosity, permeability and fluid flow characteristics of geothermal resources. We acquired fracture length, aperture, intensity and topological data from remotely sensed images and surface exposures of the Cuernos de Negros region and compared these data with well cores and thin sections from the underlying active geothermal reservoir: the Southern Negros Geothermal Field, west central Philippines. We show that the fracture attributes of the analogue and reservoir are best described by a power law distribution of fracture length and aperture intensity across six to eight orders of magnitude. This characterization of outcrop and borehole fractures validates the use of surface exposures as analogues for the Southern Negros Geothermal Field reservoir rocks at depth. An observed change in the scaling exponent in the 100–500 m length scale suggests that regional to sub-regional fracture systems scale differently from those at the meso- and macroscale, which may be a strata-bound effect or a sampling issue. Topological analyses show a dominance of Y-nodes and doubly connected branches, that indicates a high degree of fracture connectivity, which is important for effective fluid flow.Supplementary Material: Slopes, coefficient of determination and Aikake information criterion values of the cumulative frequency v. length and aperture plots of all fracture transects are available at https://doi.org/10.6084/m9.figshare.c.4960559Thematic collection: This article is part of the The Geology of Fractured Reservoirs collection available at: https://www.lyellcollection.org/cc/the-geology-of-fractured-reservoirs

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Rigid and non-rigid micro-plates: Philippines and Myanmar-Andaman case studies

Cited by 14 publications

References 27 publications

Shallow Seismicity and the Classification of Structures in the Lau Back‐Arc Basin

Shallow Seismicity and the Classification of Structures in the Lau Back‐Arc Basin

Tectonic Evolution of the Southern Negros Geothermal Field and Implications for the Development of Fractured Geothermal Systems

Fracture attribute and topology characteristics of a geothermal reservoir: Southern Negros, Philippines

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