Postglacial Mw 7.0–7.5 Earthquakes on the North Olympic Fault Zone, Washington

2020 ◽  
Author(s):  
Elizabeth R. Schermer ◽  
Colin B. Amos ◽  
William Cody Duckworth ◽  
Alan R. Nelson ◽  
Stephen Angster ◽  
...  
Keyword(s):  
Fault Zone ◽  
Single Event ◽  
Fault Rupture ◽  
Time Intervals ◽  
Slip Rates ◽  
Permanent Strain ◽  
Rupture Length ◽  
The North ◽  
Slip History ◽  
History Of

ABSTRACT Holocene crustal faulting in the northern Olympic Peninsula of Washington State manifests in a zone of west-northwest-striking crustal faults herein named the North Olympic fault zone, which extends for ∼80  km along strike and includes the Lake Creek–Boundary Creek fault to the east and the Sadie Creek fault and newly discovered scarps to the west. This study focuses on the Sadie Creek fault, which extends for >14  km west-northwest from Lake Crescent. Airborne light detection and ranging (lidar) imagery reveals the trace of the Sadie Creek fault and offset postglacial landforms showing a history of Holocene surface-rupturing earthquakes dominated by dextral displacement along a steeply dipping fault zone. Paleoseismic trenches at two sites on the Sadie Creek fault reveal till and outwash overlain by progressively buried forest and wetland soils developed on scarp-derived colluvial wedges. Trench exposures of complex faulting with subhorizontal slickenlines indicate dextral displacement with lesser dip slip. Correlation of broadly constrained time intervals for earthquakes at the Sadie Creek sites and those to the east along the Lake Creek–Boundary Creek fault is consistent with rupture of much of the length of the North Olympic fault zone three to four times: at about 11, 7, 3, and 1 ka, with a shorter rupture at about 8.5 ka. Dated ruptures from trenches only partially coincide with coseismic landslides and megaturbidites in Lake Crescent, indicating that some earthquakes did not trigger megaturbidites, and some turbidites were unrelated to local fault rupture. Landform mapping suggests single-event dextral displacement of 4±1  m on the Sadie Creek fault. Inferred maximum rupture length and single-event slip imply earthquake magnitudes Mw 7.0–7.5. Dextral slip rates of 1.3–2.3  mm/yr and the ∼11,000  yr slip history suggest that the North Olympic fault zone is a prominent contributor to permanent strain in the northern Cascadia fore-arc.

Recent and active deformation in the North Evia domain, a diffuse plate boundary between Eurasia and Aegean plates in the Western termination of the North Anatolian Fault. 

2021 ◽  
Author(s):  
Fabien Caroir ◽  
Frank Chanier ◽  
Virginie Gaullier ◽  
Julien Bailleul ◽  
Agnès Maillard-Lenoir ◽  
...  
Keyword(s):  
Fault Zone ◽  
Plate Boundary ◽  
Fault Zones ◽  
North Anatolian Fault ◽  
Fault System ◽  
Eurasian Plate ◽  
Slip Rates ◽  
The North ◽  
South West ◽  
North Aegean

<p>The Anatolia-Aegean microplate is currently extruding toward the South and the South-West. This extrusion is classically attributed to the southward retreat of the Aegean subduction zone together with the northward displacement of the Arabian plate. The displacement of Aegean-Anatolian block relative to Eurasia is accommodated by dextral motion along the North Anatolian Fault (NAF), with current slip rates of about 20 mm/yr. The NAF is propagating westward within the North Aegean domain where it gets separated into two main branches, one of them bordering the North Aegean Trough (NAT). This particular context is responsible for dextral and normal stress regimes between the Aegean plate and the Eurasian plate. South-West of the NAT, there is no identified major faults in the continuity of the NAF major branch and the plate boundary deformation is apparently distributed within a wide domain. This area is characterised by slip rates of 20 to 25 mm/yr relative to Eurasian plate but also by clockwise rotation of about 10° since ca 4 Myr. It constitutes a major extensional area involving three large rift basins: the Corinth Gulf, the Almiros Basin and the Sperchios-North Evia Gulf. The latter develops in the axis of the western termination of the NAT, and is therefore a key area to understand the present-day dynamics and the evolution of deformation within this diffuse plate boundary area.</p><p>Our study is mainly based on new structural data from field analysis and from very high resolution seismic reflexion profiles (Sparker 50-300 Joules) acquired during the WATER survey in July-August 2017 onboard the R/V “Téthys II”, but also on existing data on recent to active tectonics (i.e. earthquakes distribution, focal mechanisms, GPS data, etc.). The results from our new marine data emphasize the structural organisation and the evolution of the deformation within the North Evia region, SW of the NAT.</p><p>The combination of our structural analysis (offshore and onshore data) with available data on active/recent deformation led us to define several structural domains within the North Evia region, at the western termination of the North Anatolian Fault. The North Evia Gulf shows four main fault zones, among them the Central Basin Fault Zone (CBFZ) which is obliquely cross-cutting the rift basin and represents the continuity of the onshore Kamena Vourla - Arkitsa Fault System (KVAFS). Other major fault zones, such as the Aedipsos Politika Fault System (APFS) and the Melouna Fault Zone (MFZ) played an important role in the rift initiation but evolved recently with a left-lateral strike-slip motion. Moreover, our seismic dataset allowed to identify several faults in the Skopelos Basin including a large NW-dipping fault which affects the bathymetry and shows an important total vertical offset (>300m). Finally, we propose an update of the deformation pattern in the North Evia region including two lineaments with dextral motion that extend southwestward the North Anatolian Fault system into the Oreoi Channel and the Skopelos Basin. Moreover, the North Evia Gulf domain is dominated by active N-S extension and sinistral reactivation of former large normal faults.</p>

Surface rupture of the Greendale Fault during the Darfield (Canterbury) earthquake, New Zealand

2010 ◽  
Vol 43 (4) ◽  
pp. 236-242 ◽  
Author(s):  
M. Quigley ◽  
R. Van Dissen ◽  
P. Villamor ◽  
N. Litchfield ◽  
D. Barrell ◽  
...  
Keyword(s):  
New Zealand ◽  
Ground Surface ◽  
Vertical Displacement ◽  
Fault Rupture ◽  
Surface Rupture ◽  
Framed Structures ◽  
Rupture Length ◽  
The North ◽  
Dextral Strike Slip ◽  
East West

The Mw 7.1 Darfield (Canterbury) earthquake of 4 September 2010 (NZST) was the first earthquake in New Zealand to produce ground-surface fault rupture since the 1987 Edgecumbe earthquake. Surface rupture of the previously unrecognised Greendale Fault during the Darfield earthquake extends for at least 29.5 km and comprises an en echelon series of east-west striking, left-stepping traces. Displacement is predominantly dextral strike-slip, averaging ~2.5 m, with maxima of ~5 m along the central part of the rupture. Maximum vertical displacement is ~1.5 m, but generally < 0.75 m. The south side of the fault has been uplifted relative to the north for ~80% of the rupture length, except at the eastern end where the north side is up. The zone of surface rupture deformation ranges in width from ~30 to 300 m, and comprises discrete shears, localised bulges and, primarily, horizontal dextral flexure. At least a dozen buildings were affected by surface rupture, but none collapsed, largely because most of the buildings were relatively flexible and robust timber-framed structures and because deformation was distributed over tens to hundreds of metres width. Many linear features, such as roads, fences, power lines, and irrigation ditches were offset or deformed by fault rupture, providing markers for accurate determinations of displacement.

Holocene Rupture History of the Central Teton Fault at Leigh Lake, Grand Teton National Park, Wyoming

2019 ◽  
Vol 110 (1) ◽  
pp. 67-82 ◽  
Author(s):  
Mark S. Zellman ◽  
Christopher B. DuRoss ◽  
Glenn D. Thackray ◽  
Stephen F. Personius ◽  
Nadine G. Reitman ◽  
...  
Keyword(s):  
National Park ◽  
Optically Stimulated Luminescence ◽  
Early Holocene ◽  
Fault Rupture ◽  
Elapsed Time ◽  
Rupture Length ◽  
Open Questions ◽  
History Of ◽  
Teton Range ◽  
Lake Site

ABSTRACT Prominent scarps on Pinedale glacial surfaces along the eastern base of the Teton Range confirm latest Pleistocene to Holocene surface-faulting earthquakes on the Teton fault, but the timing of these events is only broadly constrained by a single previous paleoseismic study. We excavated two trenches at the Leigh Lake site near the center of the Teton fault to address open questions about earthquake timing and rupture length. Structural and stratigraphic evidence indicates two surface-faulting earthquakes at the site that postdate deglacial sediments dated by radiocarbon and optically stimulated luminescence to ∼10–11  ka. Earthquake LL2 occurred at ∼10.0  ka (9.7–10.4 ka; 95% confidence range) and LL1 at ∼5.9  ka (4.8–7.1 ka; 95%). LL2 predates an earthquake at ∼8  ka identified in the previous paleoseismic investigation at Granite Canyon. LL1 corresponds to the most recent Granite Canyon earthquake at ∼4.7–7.9  ka (95% confidence range). Our results are consistent with the previously documented long-elapsed time since the most recent Teton fault rupture and expand the fault’s earthquake history into the early Holocene.

Spatio-temporal behaviour of continental transform faults: implications from the late Quaternary slip history of the North Anatolian Fault, Turkey

2019 ◽  
Vol 56 (11) ◽  
pp. 1218-1238 ◽  
Author(s):  
Cengiz Zabcı
Keyword(s):  
Shear Zone ◽  
Late Quaternary ◽  
Slip Rate ◽  
Secondary Structures ◽  
North Anatolian Fault ◽  
Marmara Region ◽  
Temporal Behaviour ◽  
The North ◽  
Slip History ◽  
History Of

The slip history of the North Anatolian Fault (NAF) is constrained by displacement and age data for the last 550 ka. First, I classified all available geological estimates as members of three groups: Model I for the eastern, Model II for the central, and Model III for the western segments where the North Anatolian Shear Zone gradually widens from east to west. The short-term uniform slip solutions yield similar results, 17.5 +4/–3.5 mm/a, 18.9 +3.7/–3.3 mm/a, and 16.9 +1.2/–1.1 mm/a from east to the west. Although these model rates do not show any significant spatial variations among themselves, the correlation with geodetic estimates, ranging between 15 mm/a and 28 mm/a for different sections of the NAF, displays significant discrepancies especially for the central and western segments of the fault. Discrepancies suggest that most strain is accumulated along the NAF, but some portion of it is distributed along secondary structures of the North Anatolian Shear Zone. The deformation rate is constant at least for the last 195 ka, whereas the limited number of data show strain transfer from northern to the southern strand between 195 and 320 ka BP in the Marmara Region when the incremental slip rate decreases to 13.2 +3.1/–2.9 mm/a for the northern strand of the NAF. Considering the possible uncertainties of incremental displacements and their timings, more studies on slip rate are needed at different sites, including major structural elements of the North Anatolian Shear Zone. Although most of the strain is localized along the main displacement zone, the NAF, secondary structures are still capable of generating earthquakes that can hardly reach Mw 7.

Seismicity of Northern Anatolia

1976 ◽  
Vol 66 (3) ◽  
pp. 843-868
Author(s):  
James W. Dewey
Keyword(s):  
Fault Zone ◽  
Normal Fault ◽  
Large Earthquake ◽  
Field Studies ◽  
North Anatolian Fault ◽  
Time Intervals ◽  
Western Turkey ◽  
The North ◽  
Level Of Activity ◽  
Fault Scarps

abstract Earthquakes of magnitude 5.0 and greater that occurred in 1930-1972 in northern Anatolia have been relocated in order to define more accurately the characteristics of recent seismicity. The revised epicenters were determined either by joint epicenter determination (JED) or singly, with travel-times modified by JED-calculated source-station adjustments. Calibration epicenters were assigned on the basis of published field studies of the earthquakes. Many characteristics of the occurrence of magnitude 5.0 and greater earthquakes on the North Anatolian fault are similar to characteristics of small-earthquake seismicity on California's San Andreas fault. Earthquakes tend to be concentrated on or near particular sections of the North Anatolian fault, suggesting intrinsic differences in mechanical properties along the fault. The relocated epicenters support the hypothesis that fault rupture in large and great earthquakes will begin in regions of small and moderate earthquakes; the rupture of the large earthquake then propagates into sections of the fault that normally have a low level of activity. From 1939 through 1967, seven earthquakes of magnitude 6.8 or greater ruptured the North Anatolian fault from east to west for a distance of 800 km. Several sections of the fault zone were active before the occurrence of the large earthquakes of 1939-1967. Foreshock activity also extended tens of kilometers away from the fault zone. The time intervals between successive magnitude 6.0 or greater earthquakes on the fault are not consistent with a constant velocity of source migration; a model is proposed here in which these time intervals are equal to the duration of nonelastic effects precursory to the earthquakes. In western Turkey, the burst of normal-fault earthquakes in 1969-1970 was concentrated in distinctly separated source areas. The distribution of aftershocks to the earthquake of March 28, 1970 suggests that the surface fault scarps accompanying this earthquake are a distorted representation of the normal fault plane at depth.

The Mount Hood fault zone, active faulting at the crest of the dynamic Cascade Range, north-central Oregon, USA

2021 ◽  
pp. 49-71
Author(s):  
Ian P. Madin ◽  
Ashley R. Streig ◽  
Scott E.K. Bennett
Keyword(s):  
Fault Zone ◽  
Active Volcano ◽  
Cascade Range ◽  
Active Faulting ◽  
Slip Rates ◽  
North Central ◽  
Fault Segment ◽  
The North ◽  
Timing Data ◽  
Mount Hood

ABSTRACT The Mount Hood fault zone is a N-trending, ~55-km-long zone of active faulting along the western margin of the Hood River graben in north-central Oregon. The Mount Hood fault zone occurs along the crest of the Cascade Range and consists of multiple active fault segments. It is presently unclear how much Hood River graben extension is actively accommodated on the fault zone, and how Cascade intra-arc extension accommodates regional patterns of clockwise rotation and northwest translation of crustal blocks in the Pacific Northwest region of the United States. Evidence for Holocene activity on the Mount Hood fault zone was discovered in 2009 after acquisition of high-resolution lidar topography of the area. This trip will visit sites displaying evidence of Holocene surface rupture on fault strands within the Mount Hood fault zone. Day 1 starts with a two-hour drive from Portland to Mount Hood, a 3429-m-high glaciated active volcano, where we will visit sites south of the summit along the Twin Lakes fault segment, including several fault scarps and two sites where dating of offset buried soils constrains the timing of the most recent surface-rupturing event to the Holocene. Day 1 includes two hikes of ~1 km and will be partly cross-country. The trip will overnight at the historic Timberline Lodge, an architectural masterpiece from the Civilian Conservation Corps (1933–1942) era, located at tree line on the southern flank of Mount Hood. Day 2 will visit sites north of the summit, stopping along the Blue Ridge fault segment to view the site of 2011 paleoseismic trenches and an offset glacial moraine. We will visit an unusual uphill-facing scarp in coarse talus along the Gate Creek fault segment near the north end of the Mount Hood fault zone. We will conclude Day 2 with a short hike into the Mark O. Hatfield Wilderness along the Gate Creek fault segment to view evidence of a surface-rupturing earthquake that occurred only a few centuries ago, illuminated by a nearby paleoseismic trench hand-dug in 2020. Our neotectonic and paleoseismic data are among the first efforts to document and characterize seismic sources within the Mount Hood fault zone. However, even with our new age data, fault slip rates and earthquake recurrence remain poorly constrained. With our limited earthquake timing data, it is not clear whether all segments of the Mount Hood fault zone rupture together as a ≥ M 7 earthquake, or alternatively, if the fault segments rupture independently in a sequence of smaller ~M 6–sized events.

Reactivation history of the North Anatolian fault zone based on calcite age-strain analyses

Geology ◽  
2019 ◽  
Vol 47 (5) ◽  
pp. 465-469 ◽  
Author(s):  
Perach Nuriel ◽  
John Craddock ◽  
Andrew R.C. Kylander-Clark ◽  
I. Tonguç Uysal ◽  
Volkan Karabacak ◽  
...  
Keyword(s):  
Fault Zone ◽  
North Anatolian Fault ◽  
North Anatolian Fault Zone ◽  
The North ◽  
History Of
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