Since 2003, 39 small earthquakes have been detected offshore central Oregon in the nominally locked part of the Cascadia subduction zone, where very little seis- mic activity has been recorded in spite of a paleo-seismic record of great subduction events. Although the regional earthquake bulletin reports depths of 29 and...
Signals from the R/V Langseth’s tuned airgun array were recorded on an array of 33 EarthScope FlexArray seismometers deployed in the Oregon Coast Range from 43.5° to 45°N as part of the 2012 Ridge2Trench experiment to image the structure of the Juan de Fuca plate. This segment of the Juan...
Both travel times and amplitudes of large offset refracted and reflected arrivals
observed during GLIMPCE (Great Lakes International Multidisciplinary Program on
Crustal Evolution) along line A in Lake Superior have been modeled using two-dimensional
ray tracing techniques. Forward modeling was used to iteratively refine an
initial velocity model that was...
Methane hydrates and biohydrogen are two disparate subjects that are of interest in the growing field of alternative energy research. However, before commercial use becomes a viable option, each has challenges that need to be overcome. Methane hydrates require large investments of time and capital to locate. In this thesis,...
The south central Chilean margin is one of the most seismically active subduction zones on Earth, generating some of the largest earthquakes on the planet, including the largest ever recorded in 1960 near Valdivia, Chile (Mw 9.5). Using the 15 km streamer and 6600 in3 tuned seismic airgun array aboard...
This thesis presents elastic finite difference simulations of two dimensional wavefield propagation for line-9, recorded during the 1993 part of the multi-institutional, multi-year Mendocino Triple Junction (MTJ) Seismic Experiment. Line-9 is a high-resolution, large-aperture seismic profile oriented in north-south direction, extending from the subduction regime north of the MTJ to...
Magnetic and gravity modelling was completed along two E-W transects offshore central Oregon. These models indicate that the backstop-forming western edge of the Siletz terrane has a seaward dip of approximately 40° to 49° at 44°48'N, shallowing to ~28° at 44°1 1 'N. This is a well-determined result, given available...
A 3D seismic volume was acquired summer 2000 over the southern end of Hydrate Ridge (FIR), an anomalously shallow ridge 100 km offshore Newport, Oregon. The survey followed a succession of scientific expeditions aimed at studying the gas hydrates present in the shallow subsurface that gave the name to the...
Multiple earthquake events have been recorded off the coast of Oregon, yet their locations have great uncertainty. The largest source of uncertainty is the simple models of the crust that are used to interpret seismic recordings. Because the relationship between earthquake locations and crust are diagnostic of tectonic activity, it...
To investigate the dynamic response of the outer accretionary wedge updip from the patch of greatest slip during the Mw8.8 2010 Maule earthquake, 10 Ocean Bottom Seismometers (OBS) were deployed from May 2012 to March 2013 in a small array with an inter-instrument spacing of ~10 km. Nine instruments were...
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Anne M. Tréhu
To investigate the dynamic response of the outer accretionary wedge updip from
The Gorda Escarpment (40.4° N and from 126° W to 124.7° W) is a topographic high which is the eastern portion of the Mendocino Transform Fault. The Vizcaino Block is the anomalously shallow portion of the Pacific plate immediately south of the Gorda Escarpment. Sediments of the Vizcaino Block record...
Seismic refraction data collected in 1985 by the USGS were used in
this study to derive the P and S velocity structure of the crust beneath the
Gulf of Maine. The data quality differs among instruments and is affected
by surficial lateral heterogeneities, a ringy source signature and
reverberations. Velocity...
The Queen Charlotte Fault system is a segment of the North America - Pacific
plate boundary. From 45 Ma - 5 Ma, plate motion has been primarily translational.
Since 5 Ma, transpression has been the dominant mode of interaction. The plate
boundary west of the Queen Charlotte Islands is characterized...
Several approaches to interpreting the Cascadia paleoseismic record are
used to derive relationships between fault area, slip, and moment and to compare the
results with the scaling relationships determined by Somerville et al. (2015) for recent
subduction-zone events. In two models (CA12a and CA12b), taken from Goldfinger
et al. (2012),...
Full Text:
Paleoseismic Record
by Anne M. Tréhu
This electronic supplement contains figures and a table summarizing the
During Ocean Drilling Program Leg 204, 80 in situ measurements of
subseafloor temperature were made; 68 of these showed good frictional
pulses on insertion and extraction from the seafloor and were used to
constrain the subsurface temperature. Considering uncertainties from
various sources, uncertainties in the in situ temperatures are estimated...
Several approaches to interpreting the Cascadia paleoseismic record are
used to derive relationships between fault area, slip, and moment and to compare the
results with the scaling relationships determined by Somerville et al. (2015) for recent
subduction-zone events. In two models (CA12a and CA12b), taken from Goldfinger
et al. (2012),...
Full Text:
Cascadia Paleoseismic Record
by Anne M. Tréhu
Abstract Several approaches to interpreting the Cascadia
Several approaches to interpreting the Cascadia paleoseismic record are used to derive relationships between fault area, slip, and moment and to compare the results with the scaling relationships determined by Somerville et al. (2015) for recent subduction-zone events. In two models (CA12a and CA12b), taken from Goldfinger et al. (2012),...
The dense Corvallis array deployed in January of 2022 aided in the high-resolution study of local geology. This array was made of 177 SmartSolo 3-component 5 Hz geophones around Corvallis, with a 93 geophone profile going west towards Bald Hill for approximately 5 km at an average of 64 m...
Strong ground motions from earthquakes can result in the reduction of the shear modulus and wave propagation characteristics of soils, and can produce liquefaction and cyclic softening during shaking and for some time following the seismic event. While the ground motions produced from controlled blasting are different than those in...
Residents in South Falls City, a small town in the foothills of Oregon's Coast Range, battle intense flooding during the rainy season. Disagreements about surface water management pit neighbor against neighbor, but preliminary evidence suggests that groundwater flooding is an underlying cause. OSU researchers pair the emerging literature on groundwater...
Distributed deformation in the backarc of Cascadia is complex. Off the west coast lies the Cascadia convergent margin. East of the plate boundary, clockwise rotation of the Oregon Coast Range block with respect to stable North America influences backarc deformation, causing extensional faults in southeast Oregon, contraction folding in southeast...
In the past several years, international interest in gas hydrates in marine sediments has
increased considerably because of increasing recognition that the large volume of gas stored
in hydrates or trapped beneath them is a significant fraction of the global methane budget,
and may therefore be a source of energy...
Models of magnetic and gravity anomalies along two E-W transects offshore central Oregon, one of which is coincident with a detailed velocity model, provide quantitative limits on the structure of the subducting oceanic crust and the crystalline backstop. The models indicate that the backstop-forming western edge of the Siletz terrane,...
The Vizcaino block is an anomalously shallow region of the western U.S continental margin located southwest of the Mendocino triple junction. It originated as part of the accretionary prism of the North America plate and was transferred to the Pacific plate in the Miocene as the Pacific-North America plate boundary...
Three-dimensional gravity analysis is the process of removing the predictable
components from the free-air gravity anomalies and has proven to be useful for
interpreting the subsurface structures and active processes at mid-ocean ridges. The
three-dimensional effects of the seafloor and Moho topography, assuming a constant
crustal thickness and constant crust...
The passive charge compensation (PCC) technique was introduced for switched capacitor (SC) circuit to increase the slew rate and enhance the linearity performance, as PCC techniques are used on the Delta-Sigma modulator (DSM) in ADC circuitry. The PCC technique of the project was applied to the design of a SC...
Portions of Yellowstone Lake sit on top of a vigorous but not well understood hydrothermal system situated in a region of intense geologic and environmental forcings. A heat flow study conducted over the Stevenson Island Vent Field (SIVF), a vent field at the bottom of Yellowstone Lake underlain by an...
End users develop more software than any other group of programmers, using software authoring devices such as e-mail filtering editors, by-demonstration macro builders, and spreadsheet environments. Despite this, there has been only a little research on finding ways to help these programmers with the dependability of the software they create....
Survival of ecological systems pivot on critical moments. In the arid John Day Basin of Eastern Oregon, extensive restoration of the stream and floodplain focused on supporting salmon has been ongoing for the past 20 years, but recurring short periods of extreme temperature increase and low flows result in mortality...
In coastal and ocean engineering, understanding the ocean environment and the forces from waves, tsunamis and waterborne debris on structures and floating bodies is an important aspect of designing safe and effective infrastructure. Understanding the impact of these forces on structures becomes an important question in the design process. Answering...
Cross-laminated timber (CLT) is revolutionizing the use of wood in the construction sector of North America as a solution for walls and diaphragms in mid-rise or even high-rise timber structures on account of its environmental advantages, high strength-to-weight ratio, fire-safety performance, and propensity for prefabrication. However, considering the hygroscopic nature...
CLT is becoming global. New countries and regions increasingly realize the potential of what can be done with CLT. As a result, new markets are forming and new companies are entering the industry. Every new region or country that opens its doors to CLT has its own challenges and opportunities....
The aim of this research is to understand and quantify the modeling differences between CSiBridge and OpenSees, and to determine sensitive model parameters. When designing bridges for the high seismic region of California, the California Department of Transportation (Caltrans) performs nonlinear time history analysis of their bridge models. For three-dimensional...
The development of cross-laminated timber (CLT) panel technology has opened up new opportunities for wood in tall buildings. Several characteristics including seismic performance and speed of construction have raised interest among designers. As CLT gains acceptance in the industry, alternative structural solutions need to be investigated to improve performance of...
Three successful vertical seismic profiles (VSPs) were acquired during
Ocean Drilling Program (ODP) Leg 204 at South Hydrate Ridge. The
data confirm earlier results from ocean bottom seismometer data and
analysis of moveout from common midpoint reflection data that the
average velocity between the seafloor and the bottom-simulating reflector
(BSR)...
Bathymetry and magnetic anomalies indicate that a seamount on the Juan de Fuca plate has been subducted beneath the central Cascadia accretionary complex and is now located similar to 45 km landward of the deformation front. Passage of this seamount through the accretionary complex has resulted in a pattern of...
Ocean Drilling Program (ODP) Leg 204 to Hydrate Ridge, located on the continental slope offshore Oregon (USA), was the first drilling expedition dedicated to understanding gas hydrate processes in accretionary complexes and provided a testbed for a number of different techniques for estimating the gas hydrate content of sediments. It...
High‐resolution three‐dimensional (3‐D) seismic reflection data acquired on the R/V Thomas G. Thompson in 2000 reveal a pair of bottom simulating reflections (BSRs) across a broad region of southern Hydrate Ridge, offshore Oregon. The primary BSR (BSRp) is a regionally extensive reflection that lies 120–150 m below seafloor and exhibits...
Seismic reflection profiles shot across the Cascadia forearc show that a 5–15 km thick band of reflections, previously interpreted as a lower crustal shear zone above the subducting Juan de Fuca plate, extends into the upper mantle of the North American plate, reaching depths of at least 50 km. In...
From December 2006 to November 2011, the Pacific Northwest Seismic Network (PNSN)
reported 467 earthquakes in a swarm 60 km east of Mt Hood near the town of Maupin, Oregon.
The swarm included 20 M[subscript D] ≥ 3.0 events, which account for over 80 per cent of the cumulative
seismic...
The Queen Charlotte Fault is a transpressive transform plate boundary between the Pacific and North American plates offshore western Canada. Previous models for the accommodation of transpression include internal deformation of both plates adjacent to the plate boundary or oblique subduction of the oceanic plate; the latter has been the...
As the Mendocino Triple Junction migrates northward along the California margin it is widely presumed to leave a "slab-free" or "asthenospheric" window in its wake. A 250-km-long south-north seismic refraction-reflection profile crossing the transition from transform to subduction regimes allows us to compare and contrast crust and upper mantle of...
In 1989, we conducted an onshore/offshore seismic experiment to image the crustal structure of the Cascadia forearc. In this paper, we discuss the processing and interpretation of a multichannel seismic reflection profile across the continental margin that was collected as part of this effort. This profile reveals several features of...
A simultaneous inversion for velocity and attenuation structure using multiple seismic attributes has been applied to refraction data from the 1986 GLIMPCE Lake Superior experiment. The seismic attributes considered include envelope amplitude, instantaneous frequency, and travel time of first arrival data. Instantaneous frequency is converted to t* using a matching...
Diking and channelizing in the Toppenish Creek basin, associated with irrigated agricultural development, has altered its natural ecosystem function and hydraulic processes. We seek to answer two research questions: if surface waters are diverted for aquifer recharge in the winter, will this water be available for ecosystem function in the...
The seismic response of deep deposits of liquefiable and cyclic-softening susceptible soils has presented the geotechnical profession with significant engineering challenges. Strong ground motions may serve to soften soils under cyclic shear, trigger liquefaction, and produce damaging displacements as a consequence. This study improves the understanding of the in-situ, nonlinear,...
This dissertation explores the idea of applying machine learning technologies to help computer users find information and better organize electronic resources, by presenting the research work conducted in the following three applications: FolderPredictor, Stacking Recommendation Engines, and Integrating Learning and Reasoning.
FolderPredictor is an intelligent desktop software tool that helps...
Contiential margins on plate boundaries are complex systems with morphologies and characteristics dictated by the interplay of sediment deposition and erosion, tectonic faulting, folding, and strong ground motion generating mass wasting events. With ever increasing advances in high-resolution remote sensing techniques these systems are increasingly becoming illuminated.
A ~120 km...
Damage estimates to the built environment from tsunamis are important for disaster mitigation, including planning emergency response and recovery. This dissertation evaluates the damage states of buildings in a small urban coastal city, Seaside, Oregon, from tsunami hazards generated by a Cascadia Subduction Zone (CSZ) event. This study is separated...
The Mahakam Delta which was once among the largest mangrove forests in Indonesia, has been subjected to dramatic changes in structure and function due to massive shifts from mangrove forest to shrimp ponds and oil and gas development. To understand the impacts of mangrove loss to the greenhouse gas (GHG)...
Microbial communities in aquatic systems are dominant drivers of chemical transformation, including contaminants of emerging concern (CECs). This study quantified shifts in microbial communities and their relationship to shifts in chemical composition in surface waters in the Willamette Valley, Oregon. In addition to bulk chemical composition shifts, the relationship between...
The Central Oregon High Cascade Range is an anomalously mafic segment of the Cascade Arc due to ongoing intra-arc extension, which allows most magmas to traverse the crust without stalling and evolving to more evolved compositions. North Sister, a composite volcano in this arc segment, has produced a seemingly monotonous...
During the last 15 years, numerous geophysical surveys and geological sampling and coring expeditions have helped to characterize the tectonic setting, subsurface stratigraphy, and gas hydrate occurrence and abundance within the region of the accretionary wedge surrounding Hydrate Ridge. Because of these investigations, Hydrate Ridge has developed as an international...
While bubble plumes have been acoustically imaged in the water column above marine gas
hydrate deposits in many studies, little is known about the temporal variation in plume intensity. In
July 2008, we conducted surveys using 3.5 and 12 kHz echosounders and a 75 kHz acoustic Doppler
current profiler (ADCP)...
This paper presents a seismic sequence and structural analysis of a high-resolution three-dimensional seismic reflection survey that was acquired in June 2000 in preparation for Ocean Drilling Program (ODP) Leg 204. The seismic data were correlated with coring and logging results from nine sites drilled in 2002 during Leg 204....
Drilling in the Cascadia accretionary complex enable us to evaluate the contribution of dehydration reactions and gas hydrate dissociation to pore water freshening. The observed freshening with depth and distance from the prism toe is consistent with enhanced conversion of smectite to illite, driven by increase in temperature and age...
While bubble plumes have been acoustically imaged in the water column above marine gas
hydrate deposits in many studies, little is known about the temporal variation in plume intensity. In
July 2008, we conducted surveys using 3.5 and 12 kHz echosounders and a 75 kHz acoustic Doppler
current profiler (ADCP)...
Submersible investigations of the Cascadia accretionary
complex have identified localized venting of methane gas
bubbles in association with gas hydrate occurrence. Acoustic
profiles of these bubble plumes in the water column in the
vicinity of Hydrate Ridge offshore Oregon provide new
constraints on the spatial distribution of these gas vents...
Wide-angle and vertical incidence seismic data from Seismic Hazards Investigations in Puget Sound (SHIPS), gravity modeling, and seismicity are used to derive two-dimensional crustal models beneath the Strait of Juan de Fuca. The Eocene volcanic Crescent-Siletz terrane is significantly thicker than previously recognized and extends from near the surface to...
In spite of an order of magnitude increase over the past 15 years in spatial sampling of the wavefield, a major uncertainty in the analysis of active source seismic data remains phase identification. This uncertainty results in part from the wide range of spatial scales of velocity heterogeneity in the...
While bubble plumes have been acoustically imaged in the water column above marine gas
hydrate deposits in many studies, little is known about the temporal variation in plume intensity. In
July 2008, we conducted surveys using 3.5 and 12 kHz echosounders and a 75 kHz acoustic Doppler
current profiler (ADCP)...
The Gorda Escarpment is a north facing scarp immediately south of the Mendocino transform fault (the Gorda/Juan de Fuca-Pacific plate boundary) between 126°W and the Mendocino triple junction. It elevates the seafloor at the northern edge of the Vizcaino block, part of the Pacific plate, ~1.5 km above the seafloor...
Two examples of Pacific rim plate boundary deformation are presented. In the first
part of the thesis crustal models are derived for the northwestern part of the Vizcaino
block in California using marine seismic and gravity data collected by the Mendocino
Triple Junction Seismic Experiment. A northwest-southeast trending kink in...
The purpose of this research study was to describe and improve understanding of the meaning of institutionalized sustainability and the role that a college president plays in institutionalizing sustainability on a community college campus. The following questions guided the research: (a) What does it mean to have sustainability “institutionalized” at...
Hydrate Ridge is an accretionary thrust ridge located on the lower slope of the central Cascadia convergent margin. Structural mapping based on two-dimensional and three-dimensional multichannel seismic reflection profiles and gridded bathymetry coupled with deep-towed sidescan sonar data and Ocean Drilling Program (ODP) biostratigraphy suggests that seafloor fluid venting patterns...
The Queen Charlotte fault (QCF) is a dextral transform system located offshore of southeastern Alaska and western Canada, accommodating ∼4.4 cm/yr of relative motion between the Pacific and North American plates. Oblique convergence along the fault increases southward, and how this convergence is accommodated is still debated. Using seismic reflection...
The workshop was funded by the National Science Foundation (NSF), OCE Division of Ocean Sciences (Award # 1817257). This report summarizes the key findings, outcomes, and recommendations of the workshop and serves as a draft of the comprehensive roadmap.
Geophysical and biogeochemical processes associated with fluid venting from active and passive continental margins will receive significant scientific and economic attention
into the next century and are of major societal relevance. An important unknown among these interrelated processes is the role played by methane gas hydrates, at and below the...
A massive release of methane on the Cascadia Hydrate Ridge was documented
during a ROPOS program in August 1998, consistent with previously reported
observations in 1996. An extensive survey of the seafloor revealed that the
seeps lie within a narrow band trending 109 degrees. This feature parallels larger
mounds imaged...
Log and core data document gas saturations as high as
90% in a coarse-grained turbidite sequence beneath the gas
hydrate stability zone (GHSZ) at south Hydrate Ridge, in the
Cascadia accretionary complex. The geometry of this gas-saturated
bed is defined by a strong, negative-polarity
reflection in 3D seismic data. Because...
Seismic data and seafloor samples indicate the presence of free gas, gas hydrate, and
fluid seeps south of the Gorda Escarpment, a topographic feature that marks the eastern
end of the Gorda/Pacific transform plate boundary southwest of Cape Mendocino,
California. In spite of high sedimentation rates and high biological productivity,...
The Queen Charlotte Fault (QCF) is a major strike-slip fault that forms the boundary between the Pacific and North American plates from 51° to 58° N. Near 53.2° N, the angle of oblique convergence predicted by the Mid-Ocean Ridge VELocity (MORVEL) interplate pole of rotation decreases from >15° in the...
Increasing public awareness that the Cascadia subduction zone in the Pacific Northwest is capable of great earthquakes (magnitude 9 and greater) motivates the Cascadia Initiative, an ambitious onshore/offshore seismic and geodetic experiment that takes advantage of an amphibious array to study questions ranging from megathrust earthquakes, to volcanic arc structure,...
Using temperature gradients measured in 10 holes at 6 sites, we generate the first high fidelity heat flow measurements from Integrated Ocean Drilling Program drill holes across the northern and central Lesser Antilles arc and back arc Grenada basin. The implied heat flow, after correcting for bathymetry and sedimentation effects,...
Hydrate Ridge has the distinction of hosting the first documented subduction-driven cold seep system that supports chemosynthetic life by Anaerobic Oxidation of Methane as well as the most widely researched methane hydrate setting at any active continental margin. Today this site is a vital node of Northeast Pacific regional long-term...
We used data from Cascadia Initiative and Blanco Transform Fault Zone array of ocean bottom seismometers and hydrophone to look at the seismicity and specially depth of the Central Cascadia Continental Margin events. Events were detected and located automatically with Antelope software package (Boulder Real Time Technologies). We looked at...
We used data from Cascadia Initiative and Blanco Transform Fault Zone array of ocean bottom seismometers and hydrophone to look at the seismicity and specially depth of the Central Cascadia Continental Margin events. Events were detected and located automatically with Antelope software package (Boulder Real Time Technologies). We looked at...
Methane derived authigenic carbonate (MDAC) precipitation occurs within marine sediments as a byproduct of the microbial anaerobic oxidation of methane (AOM). While these carbonates form in chemical and isotopic equilibrium with the fluids from which they precipitate, burial diagenesis and recrystallization can overprint these signals. Plane polarized light (PPL) and...
The Cascadia subduction zone has been characterized as a typical Chilean-type
subduction zone based on qualitative comparisons of plate age and convergence rate, with
simple forearc structure. However, the discovery of unusual structural styles of
deformation, variations in the morphology of the forearc, and its absence of seismic activity
suggest...
Increased water temperatures and thermal loading due to anthropogenic inputs has
been shown to negatively impact the lifecycles of aquatic organisms in riverine
systems (Poole and Berman 2001; Hannah, Malcolm et al. 2004; Quinn, Gagne et al.
2004). The studies enclosed in this thesis evaluate and quantify the heat fluxes...
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Selker and Dr. AnneTrehu. I thank John
for his encouragement and assistance with the fiber optic
The overall objective of this study is to address questions concerning the long-term
mechanical strength of the lithosphere across the equatorial margin of Brazil. The
approach used in this study consists of calculating the frequency response function
estimates, also called admittance, using gravity and bathymetry data. These
experimental estimates are...
The Central Oregon High Cascade Range is an anomalously mafic segment of the
Cascade Arc due to ongoing intra-arc extension, which allows most magmas to traverse
the crust without stalling and evolving to more evolved compositions. North Sister, a
composite volcano in this arc segment, has produced a seemingly monotonous...
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committee members, Dr. Roger Nielsen, Dr. David Graham, Dr. AnneTrehu,
and graduate school representative
Heat flow analysis of the Costa Rica convergent margin is carried out for seven core sites drilled during Integrated Ocean Drilling Program (IODP) Expeditions 334 and 344 as part of the Costa Rica Seismogenesis Project (CRISP). These expeditions were designed to develop a better understanding of erosional subduction zones. Heat...
Twelve years ago I was new to the Oregon coast and eager to learn about the natural setting. Field guides were available to birds, marine mammals, tide pools, seaweeds, and forest plants. Not so geology. I looked at a field guide to rocks and minerals, but it was hard to...
By researching aspects of the geology of Redwood National and State Parks (RNSP) and
serving for two summers as a seasonal interpretive ranger, I have developed a training manual designed for fellow rangers. The descriptive nature of the manual, combined with its vivid illustrations, is designed to enable rangers of...
This thesis presents a detailed seismotectonic investigation of the Himalayan region and the Tibetan plateau as part of project HiCLIMB to explore the state of stress and the kinematics of the world’s largest continental collision zone. Using full regional waveforms for moment tensor inversion, source parameters for 107 earthquakes were...
Measuring surface heat flow at the Hikurangi Trough is key toward characterizing the local thermal regime and the influence of thermally sensitive processes such as fluid flow and slow slip. Marine heat flow data were collected during May– June 2015 in the northern Hikurangi Trough at sites seaward and landward...
Recent geophysical and geological investigations of the Tibetan plateau have given rise to conflicting models of plateau growth and deformation, where the presence and extent of partial melt in the crust could be a determining factor. Here we investigate the attenuation structure of the crust and upper mantle, as attenuation...
In order to evaluate the shallow stratigraphy along the southern Cascadia abyssal margin and northern California abyssal plain, CHIRP subbottom profiles capable of imaging individual turbidite beds in the upper tens of meters of the subsurface were collected. Reflectors imaged with the 3.5 kHz CHIRP subbottom data represent turbidite beds...
On November 6, 1988, two strong earthquakes (Mw: 7.0 and 6.8) separated
by about 13 minutes occurred in Yunnan Province, China. The aftershocks located
by Kunming Telemetered Seismic Network form a lineament approximately 120 km
long and 20 km wide with the long dimension oriented approximately N30°W. The
epicenter of...
Parallel processors are classified into two classes: shared-memory multiprocessors and distributed- memory multiprocessors. In the shared-memory system, processors communicate through a common memory unit. However, in the distributed multiprocessor system, each processor has its own memory unit and the communications among the processors are performed through an interconnection network. Thus,...
Stratigraphy and chronology are essential to sedimentological study of Earth system histories. And, stratigraphy and chronology are often challenging and interesting problems themselves. The Quaternary (2.588 Ma - present) experienced paleoenvironmental and paleo-geomagnetic variability well outside the range of the recent instrumental record, providing the opportunity to place recent observations...