Katmai National Park Research Articles

Multiple Seismogenic Processes for High-Frequency Earthquakes at Katmai National Park, Alaska: Evidence from Stress Tensor Inversions of Fault-Plane Solutions

The volcanological significance of seismicity within Katmai National Park has been debated since the first seismograph was installed in 1963, in part because Katmai seismicity consists almost entirely of high-frequency earthquakes that can be caused by a wide range of processes. I investigate this issue by determining 140 well-constrained first-motion fault-plane solutions for shallow (depth < 9 km) earthquakes occurring between 1995 and 2001 and inverting these solutions for the stress tensor in different regions within the park. Earthquakes removed by several kilometers from the volcanic axis occur in a stress field characterized by horizontally oriented σ1 and σ3 axes, with σ1 rotated slightly (12°) relative to the NUVEL1A subduction vector, indicating that these earthquakes are occurring in response to regional tectonic forces. On the other hand, stress tensors for earthquake clusters beneath several Katmai cluster volcanoes have vertically oriented σ1 axes, indicating that these events are occurring in response to local, not regional, processes. At Martin-Mageik, vertically oriented σ1 is most consistent with failure under edifice loading conditions in conjunction with localized pore pressure increases associated with hydrothermal circulation cells. At Trident-Novarupta, it is consistent with a number of possible models, including occurrence along fractures formed during the 1912 eruption that now serve as horizontal conduits for migrating fluids and/or volatiles from nearby degassing and cooling magma bodies. At Mount Katmai, it is most consistent with continued seismicity along ring-fracture systems created in the 1912 eruption, perhaps enhanced by circulating hydrothermal fluids and/or seepage from the caldera-filling lake. Manuscript received 25 April 2002.

Limnology of lakes in Katmai National Park and Preserve, Alaska: nutrients and plankton

(2002). Limnology of lakes in Katmai National Park and Preserve, Alaska: nutrients and plankton. SIL Proceedings, 1922-2010: Vol. 28, No. 2, pp. 1010-1016.

Magma storage and mixing conditions for the 1953–1974 eruptions of Southwest Trident volcano, Katmai National Park, Alaska

Between 1953 and 1974, approximately 0.5 km3 of andesite and dacite erupted from a new vent on the southwest flank of Trident volcano in Katmai National Park, Alaska, forming an edifice now known as Southwest (or New) Trident. Field, analytical, and experimental evidence shows that the eruption commenced soon after mixing of dacite and andesite magmas at shallow crustal levels. Four lava flows (58.3–65.5 wt% SiO2) are the dominant products of the eruption; these contain discrete andesitic enclaves (55.8–58.9 wt% SiO2) as well as micro- and macro-scale compositional banding. Tephra from the eruption spans the same compositional range as lava flows; however, andesite scoria (56–58.1 wt% SiO2) is more abundant relative to dacite tephra, and is the explosively erupted counterpart to andesite enclaves. Fe–Ti oxide pairs from andesite scoria show a limited temperature range, clustered around 1000 °C. Temperatures from grains found in dacite lavas possess a wider range; however, cores from large (>100 μm) magnetite and coexisting ilmenite give temperatures of ∼890 °C, taken to represent a pre-mixing temperature for the dacite. Water contents from dacite phenocryst melt inclusions and phase equilibria experiments on the andesite imply that the two magmas last resided at a water pressure of 90 MPa, and contained ∼3.5 wt% H2O, equivalent to 3 km depth if saturated. Unzoned pyroxene and sodic plagioclase in the dacite suggest that it likely underwent significant crystallization at this depth; highly resorbed anorthitic plagioclase from the andesite suggests that it originated at greater depths and underwent relatively rapid ascent until it reached 3 km, mixed with dacite, and erupted. Diffusion profiles in phenocrysts suggest that mixing preceded eruption of earliest lava by approximately one month. The lack of a compositional gap in the erupted rock suite indicates that thorough mixing of the andesite and dacite occurred quickly, via disaggregation of enclaves, phenocryst transfer from one magma to another, and direct mixing of compositionally distinct melt phases.

Limnology of two lake systems of Katmai National Park and Preserve, Alaska: Part II. Light penetration and Secchi depth

Seven large lakes in the Naknek River drainage and four in the Alagnak River drainage within the Katmai National Park and Preserve, Alaska, were surveyed once a summer during the period 1990–92 to determine baseline limnological conditions. All of the lakes are oligotrophic based on Secchi depth (SD) transparency and light penetration. Overall, SD transparency varied from 4.4 m to 17 m, the vertical light extinction coefficient (Kd) ranged from 0.411 m-1 to 0.070 m-1 and the depth of 1% light penetration (I1%) varied from 11 m to 67 m. However, because of greater light scattering, the percent of photosynthetic radiation (PAR) at SD was nearly twice as much in Battle Lake (30.4%) and Naknek Lake (32.8%), compared with the other nine lakes (mean 16%). Consequently, the ratio of I1% to SD was about 4 in these two lakes compared to a mean value of 2.6 for the other lakes. However, Battle Lake is a ‘deep blue’ calcium sulfate lake with little phytoplankton, whereas Naknek Lake contains some inorganic glacial flour and volcanic ash, as well as planktonic algae, but where sampled exhibits minimal turbidity. Biomass of planktonic algae (indexed by total chlorophyll concentration) explained most of the variation in SD (r2=0.66), Kd (r2=0.75), and I1% (r2=0.85). In contrast, neither color nor turbidity were significant predictors of any optical variable. Considering all 11 lakes, there was a significant linear relationship between SD and both Kd (r2=0.80) and I1% (r2=0.72); however, most of the unaccounted for variation was attributed to Battle Lake and Naknek Lake. Although changes in water transparency are often linked to changes in algal biomass (chlorophyll), simple measures of SD transparency alone may not be appropriate for assessing whole-scale watershed or regional changes toward oligotrophication or eutrophication in lakes of the remote and pristine Katmai National Park and Preserve.

Tephrochronology of the Brooks River Archaeological District, Katmai National Park and Preserve, Alaska: what can and cannot be done with tephra deposits

Abstract The Brooks River Archaeological District (BRAD) in Katmai National Park and Preserve is a classical site for the study of early humans in Alaska. Because of proximity to the active Aleutian volcanic arc, there are numerous tephra deposits in the BRAD, which are potentially useful for correlating among sites of archaeological investigations. Microprobe analyses of glass separates show, however, that most of these tephra deposits are heterogeneous mixtures of multiple glass populations. Some glasses are highly similar to pyroclasts of Aniakchak Crater (160 km to the south), others are similar to pyroclasts in the nearby Valley of Ten Thousand Smokes, and some are similar to no other tephra samples from the Alaska Peninsula. Moreover, tephra deposits in any one archaeological study site are not always similar to those from nearby sites, indicating inconsistent preservation of these mainly thin, fine-grained deposits. At least 15, late Holocene tephra deposits are inferred at the BRAD. Their heterogeneity is the result of either eruptions of mixed or heterogeneous magmas, like the 1912 Katmai eruption, or secondary mixing of closely succeeding tephra deposits. Because most cannot be reliably distinguished from one another on the basis of megascopic properties, their utility for correlations is limited. At least one deposit can be reliably identified because of its thickness (10 cm) and colour stratification. Early humans seem not to have been significantly affected by these tephra falls, which is not surprising in view of the resilience exhibited by both plants and animals following the 1912 Katmai eruption.

Seismicity at the volcanoes of Katmai National Park, Alaska; July 1995–December 1997

Upper-crustal seismicity located within Katmai National Park occurs mainly within four distinct clusters originating near Martin–Mageik (MM subnet) volcanoes, Trident volcano, Katmai caldera and Snowy volcano. Analyses of earthquake frequency–magnitude distributions reveal high b-values beneath MM subnet (∼1.5) normal b-values at Trident volcano (∼1.0) and intermediate b-values at Katmai caldera (∼1.3) for all seismicity occurring between July 1995 and December 1997. Detailed analyses of subsets of b-values and hypocenter locations at MM subnet reveal a temporal increase in b-value associated with an increase in the maximum depth of seismicity. The changes occurred during a shallow earthquake swarm beneath Mageik volcano between October 16 and 25, 1996 and again in November–December 1997. Before the swarm, the weighted least squares b-value was 1.01 at MM subnet, increased to 1.59 during the swarm and remained anomalously high until April 1997. The corresponding maximum depth of seismicity is generally less than 5 km for well located earthquakes occurring after September 18, 1996, but shifted to ∼10 km during both the October 1996 swarm and the November–December 1997 period. The November–December 1997 event is not associated with an increase in the rate of seismicity or the b-value. The October 1996 swarm had a cumulative moment release of 5.0×10 20 dyn-cm, and decayed from a peak rate of 110 events per day with a modified Omori law p-value of 1.06±0.11. Modelling by the flow law with a 10 km depth limit for seismicity suggests that temperature gradients are on the order of 20–40°C km −1 in agreement with the p-value estimate. We infer that a simple pressurizing intrusion was not associated with the October swarm because higher stresses should increase seismicity and lower the b-value, the opposite of what we observed. Alternatively, an actively degassing intrusion would reduce the effective stress and increase the b-value at shallow depths while the increased stress would induce seismicity at depth. Surface temperature measurements taken at the Mageik crater lake in July 1995, and again in July 1997, revealed an increase of about 10°C in the lake water temperature, consistent with a degassing intrusive event.

Multi-year Persistence of Oil Mousse on High Energy Beaches Distant from the Exxon Valdez Spill Origin

For at least 5 yr after the Exxon Valdez spill, relatively unweathered oil mousse has persisted on the exposed rocky shores of Shelikof Strait 500 km from Prince William Sound, Alaska. Previously it was thought that oil would be rapidly removed from such geomorphic settings by wave action. Oil mousse persists at sites in Katmai National Park and Preserve (NP&P) where it was stranded high in the intertidal zone under a lag of large boulders. These boulders armor the beach, preventing waves from disturbing the substrate and its included oil. Weathering of this strandf, ed mousse has been slight — mousse sampled in 1989, 1992 and 1994 show negligible changes in polynuclear aromatic hydrocarbons compared to 11-day old Exxon Valdez crude. The preservation of this oil is due to its transport as mousse boli whose interiors largely escape weathering, followed by its sheltering in the interstices of boulder-armored beaches. The transport of mousse may allow for the long distance dispersal of less weathered, and hence still toxic oil. Our findings suggest that the low ecological sensitivity ratings previously applied to exposed, rocky shorelines need to be modified. The biological threat posed by oil stranded on the Katmai NP&P coast probably is slight because of its small amount and sequestered state. However, it still possesses the ability to be chemically toxic and could be released through disturbance of the armoring boulders by unusually high wave events.

Capacity norms on bear viewing platforms

Normative theory provides a useful paradigm for collecting and understanding information about acceptable social and environmental impact levels. Initially applied to encounters and related social contact impacts in backcountry settings, normative concepts have since been applied to a greater diversity of impacts and settings. This paper applies the normative approach to capacities on two bear‐viewing platforms at Brooks River in Katmai National Park, Alaska. A sample of 244 bear viewers visiting during two distinct viewing seasons were asked to specify the acceptable number of people on the platforms at one time. The platforms differed in design, and one was considerably larger than the other. Most viewers had and could specify their norms, and there was strong agreement about some capacities. Norms were lower and levels of agreement were higher for the lower‐use September season, and for the smaller platform. Differences in norms for the two platforms were significant (p <.001), but not as large as expected, given the size and design differences between them. Results suggest there are upper limits for platform capacities irrespective of platform size and design. Implications for designing and managing platforms, or using platform capacities to develop area capacities, are discussed.

Deformation of New Trident Volcano measured by ERS‐1 SAR interferometry, Katmai National Park, Alaska

Using Synthetic Aperture Radar (SAR) interferometry, we detect several centimeters of uplift that accumulated during two years (1993–1995) around the vent of the New Trident volcano in Alaska's Katmai National Park. The areas of image coherence correspond to fresh, blocky lavas, while coherence is lost in ash‐covered areas. From the uplift gradient we estimate the depth of a pressure source under New Trident volcano to be approximately 0.8–2.0 km. Our results show that in spite of the difficult sub‐arctic environment of southern Alaska, strain build‐up can be monitored over a two‐year period, showing the potential for global monitoring of volcano deformation using SAR interferometry.

Limnology of two lake systems of Katmai National Park and Preserve, Alaska: Physical and chemical profiles, major ions, and trace elements

Six large lakes in the Naknek River drainage and fourin the Alagnak River drainage were sampled once asummer for three summers, 1990–1992, in a baselinewater quality study of Katmai National Park andPreserve. These pristine lakes are discontinuous coldpolymictic, mixing to great depths occasionallythrough the ice-free season due to frequent winds ofcoastal storms. Cation proportions were similar amonglakes with sodium somewhat overrepresented, mostlikely due to the location at the base of the AlaskaPeninsula in proximity to the influences of thePacific Ocean. Anion proportions varied. Six Nakneklakes and one Alagnak lake were typical calciumcarbonate lakes. Chloride and sulfate wereproportionally high in the others, resulting in theextreme in a ’triple water‘ lake (Kulik Lake) and acalcium sulfate lake (Battle Lake). The high chlorideproportions were, like sodium, probably due to theinfluences of ocean spray on precipitation. The highsulfate of Naknek Lake was probably due to volcanicinfluence, and there was some evidence of localgeothermal imputs to Kulik Lake. Iron Springs Lake andCreek, which form one of Battle Lake‘s inlets, areknown to be strongly influenced by sulfur minerals.The very low alkalinity of Battle Lake was associatedwith elevated concentrations of aluminum. Thesealuminum concentrations exceeded the freshwaterchronic criterion for the protection of aquaticlife.

Review: Tourism in Katmai Country: A History of Concessions Activity in Katmai National Park and Preserve, by Frank B. Norris

Book Review| January 01 1995 Review Tourism in Katmai Country: A History of Concessions Activity in Katmai National Park and PreserveFrank B. Norris James H. Ducker James H. Ducker Search for other works by this author on: This Site PubMed Google Scholar The Public Historian (1995) 17 (1): 113–115. https://doi.org/10.2307/3378367 Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Twitter LinkedIn Tools Icon Tools Get Permissions Cite Icon Cite Search Site Citation James H. Ducker; Review. The Public Historian 1 January 1995; 17 (1): 113–115. doi: https://doi.org/10.2307/3378367 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu nav search search input Search input auto suggest search filter All ContentThe Public Historian Search This content is only available via PDF. Copyright 1995 Regents of the University of California and the National Council on Public History Article PDF first page preview Close Modal You do not currently have access to this content.

Sandstone Petrography and Diagenesis of Lower Tertiary Sedimentary Rocks Along the Eastern Shore of Katmai National Park, Southwest Alaska

Sandstone Petrography and Diagenesis of Lower Tertiary Sedimentary Rocks Along the Eastern Shore of Katmai National Park, Southwest Alaska

Characteristics of Lower Tertiary Sedimentary Rocks Along the Eastern Shore of Katmai National Park, Southwest Alaska

Characteristics of Lower Tertiary Sedimentary Rocks Along the Eastern Shore of Katmai National Park, Southwest Alaska

A comparison of gas geochemistry of fumaroles in the 1912 ash-flow sheet and on active stratovolcanoes, Katmai National Park, Alaska

Abstract Fumarolic gas samples collected in 1978 and 1979 from the stratovolcanoes Mount Griggs, Mount Mageik, and the 1953-68 SW Trident cone in Katmai National Park, Alaska, have been analysed and the results presented here. Comparison with recalculated analyses of samples collected from the Valley of Ten Thousand Smokes (VTTS) in 1917 and 1919 demonstrates differences between gases from the short-lived VTTS fumaroles, which were not directly magma related, and the fumaroles on the volcanic peaks. Fumarolic gases of Mount Griggs have an elevated total He content, suggesting a more direct deep crustal or mantle source for these gases than those from the other volcanoes.

The plinian eruptions of 1912 at Novarupta, Katmai National Park, Alaska

The three-day eruption at Novarupta in 1912 consisted of three discrete episodes. Episode I began with plinian dispersal of rhyolitic fallout (Layer A) and contemporaneous emplacement of rhyolitic ignimbrites and associated proximal veneers. The plinian column was sustained throughout most of the interval of ash flow generation, in spite of progressive increases in the proportions of dacitic and andesitic ejecta at the expense of rhyolite. Accordingly, plinian Layer B, which fell in unbroken continuity with purely rhyolitic Layer A, is zoned from >99% to ∼15% rhyolite and accumulated synchronously with emplacement of the correspondingly zoned ash flow sequence in Mageik Creek and the Valley of Ten Thousand Smokes (VTTS). Only the andesiterichest flow units that cap the flow sequence lack a widespread fallout equivalent, indicating that ignimbrite emplacement barely outlasted the plinian phase. On near-vent ridges, the passing ash flows left proximal ignimbrite veneers that share the compositional zonation of their valley-filling equivalents but exhibit evidence for turbulent deposition and recurrent scour. Episode II began after a break of a few hours and was dominated by plinian dispersal of dacitic Layers C and D, punctuated by minor proximal intraplinian flows and surges. After another break, dacitic Layers F and G resulted from a third plinian episode (III); intercalated with these proximally are thin intraplinian ignimbrites and several andesite-rich fall/flow layers. Both CD and FG were ejected from an inner vent <400 m wide (nested within that of Episode I), into which the rhyolitic lava dome (Novarupta) was still later extruded. Two finer-grained ash layers settled from composite regional dust clouds: Layer E, which accumulated during the D-F hiatus, includes a contribution from small contemporaneous ash flows; and Layer H settled after the main eruption was over. Both are distinct layers in and near the VTTS, but distally they merge with CD and FG, respectively; they are largely dacitic but include rhyolitic shards that erupted during Episode I and were kept aloft by atmospheric turbulence. Published models yield column heights of 23–26 km for A, 22–25 km for CD, and 17–23 km for FG; and peak mass eruption rates of 0.7–1x108, 0.6–2x108, and 0.2–0.4x108 kg s-1, respectively. Fallout volumes, adjusted to reflect calculated redistribution of rhyolitic glass shards, are 8.8 km3, 4.8 km3, and 3.4 km3 for Episodes I, II, and III. Microprobe analyses of glass show that as much as 0.4 km3 of rhyolitic glass shards from eruptive Episode I fell with CDE and 1.1 km3 with FGH. Most of the rhyolitic ash in the dacitic fallout layers fell far downwind (SE of the vent); near the rhyolite-dominated ignimbrite, however, nearly all of Layers E and H are dacitic, showing that the downwind rhyolitic ash is of ‘co-plinian’ rather than co-ignimbrite origin.

A geodetic network in the Novarupta area, Katmai National Park, Alaska

A small geodetic network was established in 1989 and 1990 to monitor ground deformation in the Novarupta area, Katmai National Park, Alaska. Slope distances and zenith angles for three lines were repeated in 1990. A comparison of the two surveys indicates changes that are within the error of the measurements. Mean mark‐to‐mark slope distance changes are 1.17±1.46 ppm. Two benchmarks were added to the network in 1990 to configure a five‐endpoint braced quadrilateral centered about the Novarupta dome.

Seismic evidence for magma in the vicinity of Mt. Katmai, Alaska

P‐wave traveltime delays of as much as 0.9 sec are consistently observed at one seismic station from local and regional earthquakes 70 to 150 km deep. This station is on the southwest flank of Mt. Trident, the most recently active volcano within Katmai National Park, Alaska. Delays from local shallow earthquakes are typically less than 0.3 sec, suggesting that most of the major delay results from anomalous material at depths of more than a few kilometers. This station is located near the center of a bowlshaped low in the Bouguer gravity field that is approximately 15 km in diameter and more than 25 mgals deep. These anomalies suggest, but do not prove, the presence of considerable amounts of magma in the shallow part of the crust that could have been the source for all magma erupted in the vicinity of Mt. Katmai and Mt. Trident this century.

Time‐domain electromagnetic soundings in the vicinity of Novarupta, Katmai National Park, Alaska

A time‐domain electromagnetic survey was conducted near the rhyolite dome Novarupta. We found a continuous (60 to 100 m thick) high‐resistivity surface layer, which represents the unsaturated or unaltered tephra and whose base is probably the water table. This layer is thinnest near fumaroles; the largest thin areas lie under the tephra ring surrounding Novarupta, where the altered zones extend to a depth of more than 100 m. A deeper conductive layer is associated with the top of the underlying sedimentary rocks and is inferred to indicate the depth to the pre‐eruptive surface.

Depth of the ash flow deposit in the Valley of Ten Thousand Smokes, Katmai National Park, Alaska

In anticipation of a drill hole, seismic refraction and gravity profiles acquired more than 20 years ago have been reinterpreted in light of new density data to determine the thickness of the ash flow deposit in the Valley of the Thousand Smokes (VTTS). The data show the ash flow is at least 170m thick and most likely welded in its lower portion. Its average density is ∼1800 kg m−3. Seismic velocities range from 0.6 to 1 km/sec for the deposit's unwelded 30‐to‐50m‐thick top section and 1.8 to 2.5 km/sec for the lower welded section. The data confirm the first realistic estimate of the volume of the ash flow of about 11 km³ by Curtis (1968), based on a geomorphic analysis of stream profiles.

Argillic alteration in the Novarupta Vent Region, Katmai National Park, Alaska

Secondary mineralogy in the 1912 vent region at Novarupta illustrates an alteration history that evolved from high‐temperature degassing of ejecta through surficial argillic alteration to near‐neutral, wet‐steam alteration as the posteruptive volcanic system cooled. The locallized distribution of surficial argillization appears to have been controlled mainly by fractures related to slumping and compaction in the near‐surface fallback ejecta. The fractures guiding the surviving warm, near‐neutral fumarolic fluids, however, must be connected with deeper vent structures that reach a subsurface heat source, perhaps the boiling zone of a hydrothermal system. Trace metals, including Mo, Pb, Cu, Cd, and Zn, concentrated by high‐temperature, vapor‐phase mobilization, have subsequently been partly removed by argillization processes; in contrast, Hg, Sb, Tl, Bi, and As remain high even though the fumaroles now emit only low‐temperature, near‐neutral wet steam.