The Olympic-Wallowa lineament: A new look at an old controversy

2020 ◽  
Vol 133 (1-2) ◽  
pp. 115-133
Author(s):  
Stephen P. Reidel ◽  
Karl R. Fecht ◽  
Ingrid L. Hutter (Harrold) ◽  
Terry L. Tolan ◽  
Mickie A. Chamness
Keyword(s):  
Pacific Northwest ◽  
Structural Alignment ◽  
Puget Sound ◽  
Strike Slip ◽  
Structural Deformation ◽  
Columbia Basin ◽  
Southern Boundary ◽  
The North ◽  
The Difference ◽  
Walla Walla

Abstract The Olympic-Wallowa lineament (OWL) is an alignment of geologic structures extending nearly 650 km across the Pacific Northwest (PNW) and has been a controversial feature since it was first described nearly 80 years ago. It extends from the Olympic Peninsula–Puget Sound area of western Washington to the Wallowa Mountains of northeast Oregon, crossing through the Columbia Basin and forming the southern boundary of the Pasco and Walla Walla Basins. Within the Columbia Basin, the OWL is a wide zone that aligns with >250 km of folds and faults that are part of the Yakima fold and thrust belt. Although the OWL is recognized to be active with deformation continuing from the Miocene to Recent, there are two competing end-member interpretations on the style of deformation: that of a major through-going, dextral strike-slip or oblique-slip fault and that of a series of thrusted anticlines. We focus on that portion of the OWL in the central Columbia Basin that extends from the Walla Walla River in northeast Oregon to Rattlesnake Mountain in central Washington. East of Wallula Gap, the OWL is expressed as the Wallula fault zone along the north flank of the Horse Heaven Hills anticline and the south fork of the Walla Walla River, while west of Wallula Gap, there are three structural alignments: the Rattlesnake-Wallula structural alignment, the Horse Heaven Hills–Badlands structural alignment, and the Horn Rapids–Badger Coulee structural alignment. Except for the Horse Heaven Hills anticline, the structural trends west of Wallula Gap mainly consist of a series of doubly plunging, northeast-verging anticlines. We demonstrate that the OWL consists of north-verging, thrusted anticlines whose orientation and structure are controlled by a basement fault without any evidence of strike-slip or significant oblique-slip fault movement since at least the middle Miocene. The difference in structural deformation of the portion of the OWL to the east of Wallula Gap versus that to the west appears to be controlled by the thickness of pre-basalt sediment within the central Columbia Basin and structures therein.

Attenuation patterns in the Pacific Northwest based on intensity data and the location of the 1872 North Cascades earthquake

1979 ◽  
Vol 69 (2) ◽  
pp. 531-546
Author(s):  
Stephen D. Malone ◽  
Sheng-Sheang Bor
Keyword(s):  
Pacific Northwest ◽  
Attenuation Factor ◽  
Puget Sound ◽  
Empirical Relation ◽  
Intensity Data ◽  
North Cascades ◽  
The North ◽  
The Pacific ◽  
The Difference ◽  
Eastern Washington

abstract Intensity data from 14 historic earthquakes in or near Washington State, as reported at over 300 localities, are used to study the attenuation structure in Washington. The empirical relation of Evernden (1975) is used to determine the size and depth for each earthquake and the local attenuation factor, k, for two physiographic parts of the state. The value for k in the Puget Sound region and north into Canada is 134, while k=112 is more appropriate for eastern Washington and northern Oregon. Individual local amplification factors are computed for all localities at which four or more earthquakes have been felt by averaging the difference between the computed intensity and reported intensity at each site. Using these correction factors, the intensities for the North Cascade earthquake of 1872 are used to place constraints on its size and location. It appears this earthquake may be slightly larger (magnitude 7.4) and located south and west of the original epicenter determined by Milne.

Paleoseismic and morphometric manifestation of the transition between the Western Anatolian extensional regime and the North Anatolian Fault strike-slip zone

2020 ◽  
Author(s):  
Volkan Karabacak ◽  
Taylan Sançar ◽  
Yusuf Büyükdeniz
Keyword(s):  
Strike Slip ◽  
North Anatolian Fault ◽  
Slip Zone ◽  
Asymmetry Factor ◽  
The West ◽  
Southern Boundary ◽  
Geological Evidence ◽  
The North ◽  
Morphometric Analyses ◽  
Eastern Segment

<p>The strike-slip dominated North Anatolian Fault Zone (NAFZ) prolongs to the west and furcates into several branches where shear is distributed to multiple parallel/subparallel segments. The earlier structures that resulted from the ongoing Western Anatolian extension had a key role in the fact that the western part of the NAFZ has a wider deformation zone. Although the southern boundary of this zone is controversial, it is proposed that there is a strong interaction between the deformation zones of the NAFZ and Western Anatolian Extensional Province (WAEP) along the northern margin of the Uludag Range. Since this pivotal region marks the transition between the extensional regime and continental strike-slip zone, it is necessary to increase knowledge thereof. Within this ongoing study, we focused on the morphotectonic and paleoseismologic properties of the Ulubat and Bursa faults that delimits the northern boundary of the Uludag Range. The results of the morphometric analyses (topographic symmetry factor, asymmetry factor, hypsometric curve and integral, channel concavity, and integral analyses) that performed on 79 drainage basin to the south of these faults suggested that the vertical motion in the northeastern part of the Uludag Range changes abruptly to strike-slip dominated deformation, along with Ulubat Fault, towards the west of the Bursa basin.</p><p>The 50 km length, dextral Ulubat Fault was mapped in the field by using offset physiographic features and geological evidence. We divided the ENE–WSW striking Ulubat Fault into three segments that present the releasing double-bend geometry. There are two major changes in trends up to 20 degrees between each segment. The western segment has a length of 17 km in the E-W direction. The middle segment extends toward NE with a length of 20 km. The eastern segment stretches eastward for 13 km with a southward arc-shape geometry. We conducted the first paleoseismological trench studies on middle and eastern segments of the Ulubat Fault and identified at least 6 paleoearthquakes for the last 16 ka on both segments. The paleoseismic behavioral results which are consistent with the geometric segmentation show individual ruptures on each segment. Dated surface ruptures history show that the fault has used the same single trace in Holocene and the last events occurred in 1143 AD and 170 AD along the middle and eastern segments respectively.</p><p>Although further studies are needed to evaluate the paleoseismic recurrence interval, our results show that the Ulubat Fault takes over a considerable activity in the north of Uludag Range. The field evidence and morphometric analyses around the Uludag Range sign out that the Ulubat Fault forms the southernmost member of the NAFZ strike-slip domain. The eastern segment of the dextral Ulubat Fault has vertical component while the Bursa Fault exhibits the characteristics of the WAEP towards further east. This research was supported by the Disaster & Emergency Management Authority of Turkey (UDAP project; G-18-01).</p>

scholarly journals The Value of a River

1998 ◽  
Vol 5 (1) ◽  
pp. 1 ◽  
Author(s):  
J. Stephen Lansing ◽  
Philip S. Lansing ◽  
Juliet S. Erazo
Keyword(s):  
Pacific Northwest ◽  
Ecosystem Management ◽  
Natural Capital ◽  
Puget Sound ◽  
Market Value ◽  
Biological Productivity ◽  
Salmon River ◽  
Market Values ◽  
The North ◽  
North Fork

The Skokomish river was once the most productive salmon river in Puget Sound, but since 1926 the North Fork Skokomish has been diverted for hydropower. The Skokomish tribe has fought unsuccessfully to restore natural flows. At issue is the “non-market value” of the river’s biological productivity. The value of the river as “natural capital” for the tribe is analyzed from an historical, ethnographic, and ecological perspective.Keywords: non-market values, natural capital, salmon, Pacific Northwest, Skokomish, riverine ecology, ecosystem management.

scholarly journals Basin Progress – Active Deformation Analysis by Tectonostratigraphic Elements and Geophysical Methods on North Anatolian Fault System (Eastern Marmara Region, Turkey)

2021 ◽  
Author(s):  
Bülent Doğan ◽  
Metin Aşcı ◽  
Ahmet Karakaş ◽  
Ertan Pekşen ◽  
Arzu Erener ◽  
...  
Keyword(s):  
Strike Slip ◽  
North Anatolian Fault ◽  
Fault System ◽  
Magnetic Method ◽  
Lake Basin ◽  
Active Deformation ◽  
Southern Boundary ◽  
The North ◽  
Dextral Strike Slip ◽  
Northern Branch

Abstract The Northern Branch of the North Anatolian Fault System controls and deforms the Izmit Basin and the Sapanca Lake Basin in the study area. Unlike the Sapanca Lake Basin, the oblique normal faults with WNW–ESE trending with maximum length of 5 km in the south of the basin have contributed to the deformation process in the formation of Izmit Basin. The fault sets mainly incline to the north. The N-S width of the dextral strike-slip active deformation was determined as 9 km at Izmit basin and 3.8 km at Sapanca Lake basin. Further, the minimum principal stress axes (σ3) vary in the trending ranges of N11°-74° E, which are caused by the transtensional stresses associated with strike-slip faulting in the Izmit Basin by a different tectonic source than the Sapanca Lake Basin. Besides, the crust depth of main strand of NAFS-NB was determined up to 1112 m by magnetic method. The secondary faults were determined by both magnetic and resistivity methods up to a depth of 110 m. The depression area between Izmit bay and Sapanca Lake on the northern Anatolian fault is an integrated basin with two dextral strike-slip tectonic origins. Thus, the Izmit Basin, along with the main strike-slip faulting, has been developed in the asymmetric negative flower structure, where only the southern boundary has become a fault. The Sapanca Lake Basin is a lazy-Z-shaped pull-apart system formed by the E–W trending fault as a releasing bend. A simple shear deformation ellipsoid with a long axis of approximately 35 km on the Northern Branch of the North Anatolian Fault System is defined for the Izmit – Sapanca integrated basin. Therefore, intra-basin deposits have different depths estimated from the gravity data in the Izmit – Sapanca integrated basin, and the maximum sediment thickness estimated is 2200 m in the middle of the Izmit Basin.

scholarly journals SEISMICITY of the KOPETDAG REGION in 2015

2021 ◽  
pp. 84-93
Author(s):  
G. Saryeva ◽  
N. Petrova ◽  
L. Bezmenova
Keyword(s):  
Stress Relaxation ◽  
Seismic Activity ◽  
Background Level ◽  
Strike Slip ◽  
Seismic Stations ◽  
Space And Time ◽  
The North ◽  
Seismic Activation ◽  
Rupture Plane ◽  
The Difference

In 2015, the seismicity of the Kopetdag region was monitored by the network of 32 seismic stations, including 28 digital and 4 analogue stations. The re-equipment of stationary analogue stations of Turkmenistan with digital GEOSIG equipment, which began in 2013, was continued in 2015 – 6 GEOSIG stations were added to 9 stations of this type, and the analogue equipment at the re-equipped stations was stopped. In 2015, the seismic activity A10 in the Kopetdag region was close to the background level for the period 1992–2014, while the number of weak events significantly exceeded the level of the previous year. The seismic activation along the boundaries of the crustal blocks in the north of the Iranian plate, which began in 2012, continued by the October 12, 2015 earthquake with KR=12.7, Mw=5.2. This strongest earthquake in the territory of Turkmenistan in 2015, named the Kenekesir earthquake by the name of the nearest settlement, accompanied by numerous aftershocks – more than 35000 events with KR=3–11 were located during 80 days after the mainshock within 30 km radius. The aftershock series lasted 186 days and ended in 2016. According to the complex of instrumental seismological and tectonic data, oblique-slip with equal normal and strike-slip components occurred in the source of the mainshock. The rupture plane had a southwestern strike and dipped to the northwest. The maximum ("Bath’s") aftershock occurred on November 16 with KR=11.1. Judging by its remoteness from the mainshock in space and time, and the difference in the type of movement in the source (upthrust), it was caused by stress relaxation in the environment.

Gendered Places and Depositional Histories: Reconstructing a Menstrual Lodge in the Interior Northwest

2019 ◽  
Vol 84 (3) ◽  
pp. 400-419 ◽  
Author(s):  
Molly Carney ◽  
Jade d'Alpoim Guedes ◽  
Kevin J. Lyons ◽  
Melissa Goodman Elgar
Keyword(s):  
Low Temperature ◽  
Pacific Northwest ◽  
Thin Section ◽  
Archaeological Record ◽  
Columbia Plateau ◽  
The North ◽  
Plant Remains ◽  
History Of ◽  
Experimental Firing ◽  
River Inundation

This project considered the deposition history of a burned structure located on the Kalispel Tribe of Indians ancestral lands at the Flying Goose site in northeastern Washington. Excavation of the structure revealed stratified deposits that do not conform to established Columbia Plateau architectural types. The small size, location, and absence of artifacts lead us to hypothesize that this site was once a non-domestic structure. We tested this hypothesis with paleoethnobotanical, bulk geoarchaeological, thin section, and experimental firing data to deduce the structural remains and the post-occupation sequence. The structure burned at a relatively low temperature, was buried soon afterward with imported rubified sediment, and was exposed to seasonal river inundation. Subsequently, a second fire consumed a unique assemblage of plant remains. Drawing on recent approaches to structured deposition and historic processes, we incorporate ethnography to argue that this structure was a menstrual lodge. These structures are common in ethnographic descriptions, although no menstrual lodges have been positively identified in the archaeological record of the North American Pacific Northwest. This interpretation is important to understanding the development and time depth of gendered practices of Interior Northwest groups.

The 25 October, 2018 Zakynthos (Greece) earthquake: seismic activity at the transition between a transform fault and a subduction zone.

2020 ◽  
Author(s):  
P Papadimitriou ◽  
V Kapetanidis ◽  
A Karakonstantis ◽  
I Spingos ◽  
K Pavlou ◽  
...  
Keyword(s):  
Spatial Clustering ◽  
Accretionary Prism ◽  
Velocity Model ◽  
Strike Slip ◽  
Double Difference ◽  
Strain Partitioning ◽  
Transform Fault ◽  
Fault Plane Solutions ◽  
The North ◽  
Waveform Modelling

Summary The properties of the Mw = 6.7 earthquake that took place on 25 October 2018, 22:54:51 UTC, ∼50 km SW of the Zakynthos Island, Greece, are thoroughly examined. The main rupture occurred on a dextral strike-slip, low-angle, east-dipping fault at a depth of 12 km, as determined by teleseismic waveform modelling. Over 4000 aftershocks were manually analysed for a period of 158 days. The events were initially located with an optimal 1D velocity model and then relocated with the double-difference method to reveal details of their spatial distribution. The latter spreads in an area spanning 80 km NNW-SSE and ∼55 km WSW-ENE. Certain parts of the aftershock zone present strong spatial clustering, mainly to the north, close to Zakynthos Island, and at the southernmost edge of the sequence. Focal mechanisms were determined for 61 significant aftershocks using regional waveform modelling. The results revealed characteristics similar to the mainshock, with few aftershocks exhibiting strike-slip faulting at steeper dip angles, possibly related to splay faults on the accretionary prism. The slip vectors that correspond to the east-dipping planes are compatible with the long-term plate convergence and with the direction of coseismic displacement on the Zakynthos Island. Fault-plane solutions in the broader study area were inverted for the determination of the regional stress-field. The results revealed a nearly horizontal, SW-NE to E-W-trending S1 and a more variable S3 axis, favouring transpressional tectonics. Spatial clusters at the northern and southern ends of the aftershock zone coincide with the SW extension of sub-vertical along-dip faults of the segmented subducting slab. The mainshock occurred in an area where strike-slip tectonics, related to the Cephalonia Transform Fault and the NW Peloponnese region, gradually converts into reverse faulting at the western edge of the Hellenic subduction. Plausible scenarios for the 2018 Zakynthos earthquake sequence include a rupture on the subduction interface, provided the slab is tilted eastwards in that area, or the reactivation of an older east-dipping thrust as a low-angle strike-slip fault that contributes to strain partitioning.

scholarly journals The nucleation of the Izmit and Düzce earthquakes: Some mechanical logic on where and how ruptures began

2021 ◽  
Author(s):  
Michel Bouchon ◽  
Hayrullah Karabulut ◽  
Mustafa Aktar ◽  
Serdar Özalaybey ◽  
Jean Schmittbuhl ◽  
...  
Keyword(s):  
Strike Slip ◽  
Seismic Events ◽  
Fault Geometry ◽  
Brittle Transition ◽  
The North ◽  
Impending Rupture ◽  
Natural Tendency ◽  
Ductile To Brittle Transition ◽  
Mechanical Logic ◽  
Rupture Speed

Summary In spite of growing evidence that many earthquakes are preceded by increased seismic activity, the nature of this activity is still poorly understood. Is it the result of a mostly random process related to the natural tendency of seismic events to cluster in time and space, in which case there is little hope to ever predict earthquakes? Or is it the sign that a physical process that will lead to the impending rupture has begun, in which case we should attempt to identify this process. With this aim we take a further look at the nucleation of two of the best recorded and documented strike-slip earthquakes to date, the 1999 Izmit and Düzce earthquakes which ruptured the North Anatolian Fault over ∼200 km. We show the existence of a remarkable mechanical logic linking together nucleation characteristics, stress loading, fault geometry and rupture speed. In both earthquakes the observations point to slow aseismic slip occurring near the ductile-to-brittle transition zone as the motor of their nucleation.

A review of the tectonics of the northern Middle East region

1984 ◽  
Vol 121 (6) ◽  
pp. 577-587 ◽  
Author(s):  
P. E. R. Lovelock
Keyword(s):  
Late Cretaceous ◽  
Kinematic Model ◽  
Continental Collision ◽  
Dead Sea ◽  
Plate Motion ◽  
Arabian Plate ◽  
Southern Boundary ◽  
The North ◽  
The Dead ◽  
Two Stages

AbstractThe structure of the northern part of the Arabian platform is reviewed in the light of hitherto unpublished exploration data and the presently accepted kinematic model of plate motion in the region. The Palmyra and Sinjar zones share a common history of development involving two stages of rifting, one in the Triassic–Jurassic and the other during late Cretaceous to early Tertiary times. Deformation of the Palmyra zone during the Mio-Pliocene is attributed to north–south compression on the eastern block of the Dead Sea transcurrent system which occurred after continental collision in the north in southeast Turkey. The asymmetry of the Palmyra zone is believed to result from northward underthrusting along the southern boundary facilitated by the presence of shallow Triassic evaporites. An important NW-SE cross-plate shear zone has been identified, which can be traced for 600 km and which controls the course of the River Euphrates over long distances in Syria and Iraq. Transcurrent motion along this zone resulted in the formation of narrow grabens during the late Cretaceous which were compressed during the Mio-Pliocene. To a large extent, present day structures in the region result from compressional reactivation of old lineaments within the Arabian plate by the transcurrent motion of the Dead Sea fault zone and subsequent continental collision.

Is the North Altyn fault part of a strike-slip duplex along the Altyn Tagh fault system?

Geology ◽  
2000 ◽  
Vol 28 (3) ◽  
pp. 255 ◽  
Author(s):  
Eric Cowgill ◽  
An Yin ◽  
Wang Xiao Feng ◽  
Zhang Qing
Keyword(s):  
Strike Slip ◽  
Fault System ◽  
Altyn Tagh Fault ◽  
The North ◽  
Altyn Tagh
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