#### Filter Results:

- Full text PDF available (23)

#### Publication Year

1998

2012

- This year (0)
- Last 5 years (3)
- Last 10 years (12)

#### Publication Type

#### Co-author

#### Journals and Conferences

Learn More

Groundwater recharge at Mt. Hood, Oregon, is dominated by spring snow melt which provides a natural largeamplitude and narrow-width pore-fluid pressure signal. Time delays between this seasonal groundwater recharge and seismicity triggered by groundwater recharge can thus be used to estimate large-scale hydraulic diffusivities and the state of stress in the… (More)

[1] A comparison of time series of basaltic and silicic eruptions in eastern California over the last 400 kyr with the contemporaneous global record of glaciation suggests that this volcanism is influenced by the growth and retreat of glaciers occurring over periods of about 40 kyr. Statistically significant cross correlations between changes in eruption… (More)

- M. O. Saar, M. Manga
- 2004

[1] We investigate the decrease in permeability, k, with depth, z, in the Oregon Cascades employing four different methods. Each method provides insight into the average permeability applicable to a different depth scale. Spring discharge models are used to infer shallow (z < 0.1 km) horizontal permeabilities. Coupled heat and groundwater flow simulations… (More)

- Martin O. Saar, Michael Manga, Katharine V. Cashman, Sean Fremouw
- 2001

The formation of a continuous crystal network in magmas and lavas can provide finite yield strength, dy, and can thus cause a change from Newtonian to Bingham rheology. The rheology of crystal^melt suspensions affects geological processes, such as ascent of magma through volcanic conduits, flow of lava across the Earth's surface, melt extraction from… (More)

- M. D. Covington, A. J. Luhmann, F. Gabrov, M. O. Saar, C. M. Wicks
- 2011

[1] Previous studies, motivated by understanding water quality, have explored the mechanisms for heat transport and heat exchange in surface streams. In karst aquifers, temperature signals play an additional important role since they carry information about internal aquifer structures. Models for heat transport in karst conduits have previously been… (More)

The permeability k and porosity φ of vesicular basalts are measured. The relationship between k and φ reflects the formation and emplacement of the basalts and can be related to the crystal and vesicle microstructure obtained by image analysis. Standard theoretical models relating k and φ that work well for granular materials are unsuccessful for vesicular… (More)

[1] Simple mathematical models often allow an intuitive grasp of the function of physical systems. We develop a mathematical framework to investigate reactive or dissipative transport processes within karst conduits. Specifically, we note that for processes that occur within a characteristic timescale, advection along the conduit produces a characteristic… (More)

- M. O. Saar
- 2005

[1] We measure all stable noble gases (He, Ne, Ar, Kr, Xe) in spring waters in the Oregon Cascades volcanic arc and in eastern Oregon, USA. We show that in order to estimate magmatic helium (He) contributions it is critical to simultaneously consider He isotopic ratios, He concentrations, and mixing of He components. Our component mixing analysis requires… (More)

- Martin O Saar, Michael Manga
- Physical review. E, Statistical, nonlinear, and…
- 2002

We study continuum percolation of three-dimensional randomly oriented soft-core polyhedra (prisms). The prisms are biaxial or triaxial and range in aspect ratio over six orders of magnitude. Results for prisms are compared with studies for ellipsoids, rods, ellipses, and polygons and differences are explained using the concept of the average excluded… (More)

We examine 20-yr data sets of seismic activity from 10 volcanic areas in the western United States for annual periodic signals (seasonality), focusing on large calderas (Long Valley caldera and Yellowstone) and stratovolcanoes (Cascade Range). We apply several statistical methods to test for seasonality in the seismic catalogs. In 4 of the 10 regions,… (More)