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 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...
This article summarizes the geotechnical effects of the 25 April 2015 M 7.8 Gorkha, Nepal, earthquake and aftershocks, as documented by a reconnaissance team that undertook a broad engineering and scientific assessment of the damage and collected perishable data for future analysis. Brief descriptions are provided of ground shaking, surface...
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 2014 Working Group on California Earthquake Probabilities (WGCEP 2014) presents time-dependent earthquake probabilities for the third Uniform California Earthquake Rupture Forecast (UCERF3). Building on the UCERF3 time-independent model published previously, renewal models are utilized to represent elastic-rebound-implied probabilities. A new methodology has been developed that solves applicability issues in...
Maximum earthquake magnitude (m[subscript x]) is a critical parameter in seismic
hazard and risk analysis. However, some recent large earthquakes have shown that
most of the existing methods for estimating m[subscript x] are inadequate. Moreover, m[subscript x] itself is ill-defined because its meaning largely depends on the context, and it...
The 2014 Working Group on California Earthquake Probabilities
(WGCEP14) present the time-independent component of the Uniform California
Earthquake Rupture Forecast, Version 3 (UCERF3), which provides authoritative
estimates of the magnitude, location, and time-averaged frequency of potentially
damaging earthquakes in California. The primary achievements have been to relax
fault segmentation and...
As we contemplate the future of forest landscapes under changing climate conditions and land-use demands, there is increasing value in studying historic forest conditions and how these landscapes have changed following past disturbances. Historic landscape paintings are a potential source of data on preindustrial forests with highly detailed, full-color depictions...
Pyrosomes are colonial pelagic tunicates that have fascinated marine biologists for over a century. Their name comes from the “fiery” bioluminescence that luminous organs produce at night time. Blooms of pyrosomes, identified as Pyrosoma atlanticum (Peron, 1804), have recently appeared in the North Pacific Ocean, prompting questions about environmental factors...
Managing multiple ecosystem services (ESs) across landscapes presents a central challenge for ecosystem-based management, because services often exhibit spatiotemporal variation and weak associations with co-occurring ESs. Further focus on the mechanistic relationships among ESs and their underlying biophysical processes provides greater insight into the causes of variation and covariation among...
Disease, overharvesting, and pollution have impaired the role of bivalves on coastal ecosystems, some to the point of functional extinction. An underappreciated function of many bivalves in these systems is shell formation. The ecological significance of bivalve shell has been recognized; geochemical effects are now more clearly being understood. A...
Ballast water discharges are a major source of species introductions into marine and estuarine ecosystems. To mitigate the introduction of new invaders into these ecosystems, many agencies are proposing standards that establish upper concentration limits for organisms in ballast discharge. Ideally, ballast discharge standards will be biologically defensible and adequately...
Climate changes in the Pacific Northwest, USA, may cause both retreat of alpine glaciers and increases in the frequency and magnitude of storms delivering rainfall at high elevations absent significant snowpack, and both of these changes may affect the frequency and severity of destructive debris flows initiating on the region's...
Sensor design and mission planning for satellite ocean color measurements requires careful consideration of the signal dynamic range and sensitivity (specifically here signal-to-noise ratio or SNR) so that small changes of ocean properties (e.g., surface chlorophyll-a concentrations or Chl) can be quantified while most measurements are not saturated. Past and...
Vegetation at the aquatic–terrestrial interface can alter landscape features through its growth and interactions with sediment and fluids. Even similar species may impart different effects due to variation in their interactions and feedbacks with the environment. Consequently, replacement of one engineering species by another can cause significant change in the...
Remote-sensing reflectance is easier to interpret for the open ocean than for coastal regions because the optical signals are highly coupled to the phytoplankton (e.g., chlorophyll) concentrations. For estuarine or coastal waters, variable terrigenous colored dissolved organic matter (CDOM), suspended sediments, and bottom reflectance, all factors that do not covary...
We present the results of a study of optical scattering and backscattering of particulates for three coastal sites that represent a wide range of optical properties that are found in U.S. near-shore waters. The 6000 scattering and backscattering spectra collected for this study can be well approximated by a power-law...
Oceanic waves have been found to contribute enhanced back-scattering in the direction of the illumination source in studies that assumed the ocean surface to be a random sum of waves. Here we investigate enhanced back-scattering by coherent capillary-gravity wave trains that co-exist near the crests of short gravity waves in...
Narrow angle light scattering measurements were made for various sizes of spherical particles suspended in water. These were compared to calculated theoretical scattering values as derived from the theory of Mie (1908). Through measurements with different particle concentrations at angles between 0.2° and 0.7° the effect of the unscattered main...
We examine and compare near-forward light scattering that is caused by turbulence and typical particulate assemblages in the ocean. The near-forward scattering by particles was calculated using Mie theory for homogeneous spheres and particle size distributions representative of natural assemblages in the ocean. Direct numerical simulations of a passive scalar...