Publications

Fire is a particularly important control on the carbon (C) balance of the boreal forest, and fire-return intervals and fire severity appear to have increased since the late 1900s in North America. In addition to the immediate release of stored C to the atmosphere through organic-matter combustion, fire also modifies soil conditions, possibly affecting C exchange between terrestrial and...

This preliminary assessment of (1) bed-material transport in the Hunter Creek basin, (2) historical changes in channel condition, and (3) supplementary data needed to inform permitting decisions regarding instream gravel extraction revealed the following: Along the lower 12.4 km (kilometers) of Hunter Creek from its confluence with the Little South Fork Hunter Creek to its mouth, the...

When debris flows grow by entraining sediment, they can become especially hazardous owing to increased volume, speed, and runout. To investigate the entrainment process, we conducted eight largescale experiments in the USGS debris-flow flume. In each experiment, we released a 6 m3 water-saturated debris flow across a 47-m long, ~12-cm thick bed of partially saturated sediment lining the...

Pore-fluid pressure plays a crucial role in debris flows because it counteracts normal stresses at grain contacts and thereby reduces intergranular friction. Pore-pressure feedback accompanying debris deformation is particularly important during the onset of debrisflow motion, when it can dramatically influence the balance of forces governing downslope acceleration. We consider further...

At 0258 Hawaii‐Aleutian Standard Time (HST) on 19 March 2008, a small explosion scattered altered and fresh lithic debris across a 40‐hectare area at the summit of Kilauea volcano. This explosion, the first recorded there since 1924, issued from a vent about 35 meters wide along the east wall of Halema'uma'u Crater. Ballistic fragments—the largest measuring nearly 1 meter across—were...

This assessment of bed-material transport uses methods developed in a previous study (Wallick and others, 2010) to estimate bed-material flux at the USGS Chetco River streamflow gaging station located at flood-plain kilometer 15 (14400000). On the basis of regressions between daily mean flow and transport capacity, daily bed-material flux was calculated for the period October 1, 2008 to...

This report presents 130 gas analyses and 31 related water analyses on samples collected from thermal features at Yellowstone between 2003 and 2009. An overview of previous studies of gas emissions at Yellowstone is also given. The analytical results from the present study include bulk chemistry of gases and waters and isotope values for water and steam (delta18O, dealtaD), carbon...

The first eruptive activity at Kīlauea Volcano’s summit in 25 years began in March 2008 with the opening of a 35-m-wide vent in Halema‘uma‘u crater. The new activity has produced prominent very-long-period (VLP) signals corresponding with two new behaviors: episodic tremor bursts and small explosive events, both of which represent degassing events from the top of the lava column...

We report results of yearly measurements of the diffuse CO2 flux and shallow soil temperatures collected since 2006 across two sets of tree-kill areas at Long Valley Caldera, California. These data provide background information about CO2 discharge during a period with moderate seismicity, but little to no deformation. The tree kills are located at long-recognized areas of weak thermal...

Early on the morning of October 15, 2006, two moderate earthquakes—the largest in decades—struck the Island of Hawai‘i. The first of these, which occurred at 7:07 a.m., HST (1707 UTC), was a magnitude (M) 6.7 earthquake, centered beneath Kīholo Bay on the northwestern coast of the island (19.878°N, 155.935°W), at a depth of 39 km. The second earthquake, which struck 6 minutes, 24 seconds...

In response to a request from the U.S. Department of Energy, we estimate the thickness of tephra accumulation that has an annual probability of 1 in 10,000 of being equaled or exceeded at the Hanford Site in south-central Washington State, where a project to build the Tank Waste Treatment and Immobilization Plant is underway. We follow the methodology of a 1987 probabilistic assessment...

Pacific climate is known to have varied during the Holocene, but spatial patterns remain poorly defined. This paper compiles terrestrial and marine proxy data from sites along the northeastern Pacific margins and proposes that they indicate 1) suppressed ENSO conditions during the middle Holocene between ∼8000 and 4000 cal BP with a North Pacific that generally resembled a La Niña-like...