Shallow dips of normal faults during rapid extension: Earthquakes in the Woodlark-D'Entrecasteaux rift system, Papua New Guinea

Geoffrey A. Abers; Carolyn Z. Mutter; Jia Fang

doi:10.1029/97jb00787

Shallow dips of normal faults during rapid extension: Earthquakes in the Woodlark-D'Entrecasteaux rift system, Papua New Guinea

Journal of Geophysical Research Atmospheres ◽

10.1029/97jb00787 ◽

1997 ◽

Vol 102 (B7) ◽

pp. 15301-15317 ◽

Cited By ~ 105

Author(s):

Geoffrey A. Abers ◽

Carolyn Z. Mutter ◽

Jia Fang

Keyword(s):

Papua New Guinea ◽

New Guinea ◽

Normal Faults ◽

Rift System

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Possible seismogenic shallow-dipping normal faults in the Woodlark-D'Entrecasteaux extensional province, Papua New Guinea

Geology ◽

10.1130/0091-7613(1991)019<1205:pssdnf>2.3.co;2 ◽

1991 ◽

Vol 19 (12) ◽

pp. 1205 ◽

Cited By ~ 82

Author(s):

Geoffrey A. Abers

Keyword(s):

Papua New Guinea ◽

New Guinea ◽

Normal Faults

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How fast can low-angle normal faults slip? Insights from cosmogenic exposure dating of the active Mai’iu fault, Papua New Guinea

Geology ◽

10.1130/g39736.1 ◽

2018 ◽

Vol 46 (3) ◽

pp. 227-230 ◽

Cited By ~ 9

Author(s):

S. Webber ◽

K.P. Norton ◽

T.A. Little ◽

L.M. Wallace ◽

S. Ellis

Keyword(s):

Papua New Guinea ◽

New Guinea ◽

Normal Faults ◽

Exposure Dating

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New Tectonic Reconstructions of New Guinea Derived from Biostratigraphy and Geochronology

Proc. Indon. Petrol. Assoc., Digital Technical Conference, 2020 ◽

10.29118/ipa20-g-61 ◽

2020 ◽

Author(s):

D., P. Gold

Keyword(s):

Papua New Guinea ◽

New Caledonia ◽

New Guinea ◽

Petroleum Exploration ◽

Rift System ◽

Zircon Age ◽

Eastern Australia ◽

North Eastern ◽

West Papua ◽

Tectonic Reconstructions

Biostratigraphic data from exploration wells in Papua, West Papua of Indonesia, Papua New Guinea and Australia were reviewed, revised and updated using modern stratigraphic interpretations. Revised stratigraphic interpretations were combined with zircon U-Pb geochronologic data to produce new tectonic reconstructions of the Indonesian provinces of West Papua and Papua. Zircon U-Pb geochronologic data used in this study include new results from the Papuan Peninsula, combined with existing datasets from West Papua, Papua New Guinea, eastern Australia and New Caledonia. Supplementary geochronologic data were used to provide independent validation of the biostratigraphic data. Findings from a compilation of biostratigraphic and zircon age data provide a framework to produce new tectonic models for the origin of New Guinea’s terranes. Two hypotheses are presented to explain observations from the biostratigraphic and geochronologic data. The ‘Allochthonous Terrane’ Model suggests that many of the terranes are allochthonous in nature and may have been derived from eastern Australia. The ‘Extended Rift’ Model suggests that the New Guinea Terranes may have been separated from north-eastern Australia by an elongate rift system far more extensive than previously described. These new tectonic models are essential for our geological understanding of the regional and can be used to drive successful petroleum exploration in this frontier area.

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Mixed-Mode Seismic Slip and Aseismic Creep on a Highly Active Low-Angle Normal Fault System in Papua New Guinea

10.5194/egusphere-egu2020-230 ◽

2020 ◽

Author(s):

James Biemiller ◽

Laura Wallace ◽

Luc Lavier

Keyword(s):

Papua New Guinea ◽

Normal Fault ◽

New Guinea ◽

Fault System ◽

Normal Faults ◽

Fault Mechanics ◽

Fault Rocks ◽

Near Surface ◽

Geological Evidence ◽

Seismic Slip

<p>Whether low-angle normal faults (LANFs; dip < 30&#176;) slip in large earthquakes or creep aseismically is a longstanding problem in fault mechanics. Although abundant in the geologic record, active examples of these enigmatic &#8216;misoriented&#8217; structures are rare and extension rates across them are typically less than a few mm/yr. As such, geodetic and seismological observations of LANFs are sparse and can be difficult to interpret in terms of earthquake cycles. With a long-term slip rate of ~1 cm/yr, the Mai&#8217;iu fault in Papua New Guinea may be the world&#8217;s most active LANF and thus offers an outstanding natural laboratory to evaluate seismic vs. aseismic behavior of LANFs. Here, we use new results from a campaign GPS network to determine the degree of locking vs. aseismic creep on the Mai&#8217;iu fault and evaluate these results in the context of geological evidence for mixed seismic and aseismic slip in exhumed Mai&#8217;iu fault rocks.</p><p>We derive velocities from GPS measurements with 3-4 km station spacing above the shallowest portions of the fault, which dips 21-25&#176; at the surface. Dislocation modeling of these velocities is consistent with 6-8 mm/yr of horizontal extension, corresponding to ~1 cm/yr dip-slip rates on a 27-35&#176;-dipping fault. Strain rates and vertical derivatives of horizontal stress rates derived from these velocities confirm localized extension across the fault. We compare and evaluate two interseismic locking models that fit the data best: one in which the fault deforms by shallow near-surface creep updip of a deeper zone of increased interseismic coupling which soles into a steadily creeping shear zone at depth, and one in which the fault creeps steadily downdip of a shallowly locked patch. These results combined with field and microstructural evidence from the exhumed fault rocks suggest that the fault slips by a mixture of brittle frictional (seismic slip, fracturing, and cataclastic creep) and viscous (stress-driven dissolution-precipitation creep, or pressure solution) processes. Using depth-constrained mechanical properties and stress conditions inferred from exhumed fault rocks, we model the time-dependent competition between frictional slip and viscous creep to assess where and how elastic strain accumulates along the Mai&#8217;iu fault, and whether the fault is capable of hosting or nucleating earthquakes.</p>

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