Newly Published: Chehalis River Floodplain Geomorphic Mapping

We’re pleased to announce the release of a new publication!

Geomorphic mapping of the Chehalis River floodplain, Cosmopolis to Pe Ell, Grays Harbor, Thurston, and Lewis Counties, Washington

by S. L. Slaughter and I. J. Hubert

Relative elevation model of a portion of the study area approximately 5 miles east of Montesano showing the junction of the Chehalis River floodplain with the Satsop River.

Summary:  A relative elevation model of the Chehalis River floodplain was generated using 1- and 2-meter lidar and 12-inch-resolution aerial images in order to delineate subtle landforms on the floodplain for a 110-mile reach of the Chehalis River between Pe Ell and Cosmopolis, Washington. The relative elevation model represents elevation of features on the floodplain relative to the Chehalis River’s water surface by removing downstream changes in elevation associated with the channel gradient. Subtle landform features, such as primary, secondary, and abandoned channels, sloughs, swales, and natural and artificial levees were then identified within the floodplain. This information is useful to biologists, wetland scientists, land managers, property owners, and floodplain and watershed managers. The report contains 59 pages of maps at 1:28,000-scale and two pages of text.


Two New DGER Publications Released

We’re happy to announce the release of two new DGER publications!

Geothermal Favorability Model of Washington State

by D. E. Boschmann, J. L. Czajkowski, and J. D. Bowman 

Geothermal Resource Potential Map of Washington State

Geothermal Resource Potential Map of Washington State

Summary:  Geographic Information System (GIS) modeling of statewide heat, permeability, and infrastructure data, including volcanic centers, faults, earthquakes, temperature-gradient wells, thermal springs, young silicic intrusive rocks, and transmission lines produced layers showing relative geothermal favorability in Washington State. Regional modeling like this is one way to reduce costs in geothermal exploration by helping to more precisely locate areas worthy of additional research.

Landslide and liquefaction maps for the Ocean Shores and Westport peninsulas, Grays Harbor County, Washington: Effects on tsunami Inundation zones of a Cascadia subduction zone earthquake

by S. L. Slaughter, T. J. Walsh, Anton Ypma, and Recep Cakir

Ocean Shores and Westport liquefaction susceptibility from a Cascadia subduction zone 9+ earthquake

Ocean Shores and Westport liquefaction susceptibility from a Cascadia subduction zone 9+ earthquake

Summary:  Modeling of earthquake-induced soil liquefaction from ground shaking associated with a M9+ Cascadia subduction zone earthquake was performed as part of the National Tsunami Hazard Mitigation Program for the Ocean Shores and Westport peninsulas. Earthquake-induced ground failures, such as liquefaction or landslides, may adversely affect tsunami evacuation by blocking or damaging evacuation routes; the creation of these maps will aid emergency management officials in evaluating the suitability of existing evacuation routes and assembly areas.

Happy Reading!

Jari Roloff, Geology Editor at DGER, retires

Jari Roloff

Jari at the garden of Little & Lewis, Bainbridge Island, Washington

Last Monday was Jari Roloff’s last day with the Division of Geology and Earth Resources. After 23 years with the Division eliminating extraneous parentheticals, shortening run-on sentences, and generally saving us all from embarrassment, she is leaving us to finally relax.

We will miss her witty exasperation at our more-than-occasional use of incoherent grammar and her gentle, yet critical eye for detail. We are grateful for her uncanny ability to edit while leaving the authors their ‘voice’ intact. Her artistry, style, and experienced eye are evident on every publication we’ve produced for a very long time; thanks to her refinement of graphics to the level of a pixel, some of those publications won awards.

So please raise your coffee mugs to Jari Roloff, geology editor extraordinaire, gerund master, past and present perfectionist. May her subjects and verbs always agree. More importantly, may she think back fondly on us and her time here in Geology and may she visit us often. We only hope that she’s left enough clues and dropped sufficient hints so that we can continue to not embarrass ourselves in the future.

New TsuInfo Alert newsletter has been published

TsuInfo Alert is a bi-monthly newsletter that links scientists, emergency responders, and community planners to the latest tsunami research. This newsletter is published by the Washington Department of Natural Resources, Division of Geology and Earth Resources on behalf of the National Tsunami Hazard Mitigation Program, a state/federal partnership funded through the National Oceanic and Atmospheric Administration. It is made possible by a grant from the Federal Emergency Management Agency via the Washington Military Department, Division of Emergency Management.

February (v. 16, no. 1) [PDF; 2 MB]

Dating rocks on Valentine’s Day!

Valentines Foraminifera with scale bar

DGER geologists Trevor Contreras, Michael Polenz, Annette Patton and Harley Gordon are collaborating with the University of Washington’s Burke Museum to better date Tertiary rock formations along Hood Canal. Just as with macrofossil assemblages, microscopic fossils can be used to correlate an unidentified rock with known units. These tiny fossils pack quite a punch, despite their small size. The species of fossils in a given sample can indicate the specific age of the rock and allow researchers to deduce key information about environmental conditions at the time the microfossils and their accompanying sediments were deposited. Such knowledge provides valuable insight into our understanding of the age and stratigraphy of Tertiary sandstones and mudstones exposed in the current mapping area between Discovery Bay and Quilcene.


Foraminifera, like those pictured here, are members of a group of single-celled protozoans that primarily live in marine environments. The living organisms construct chambered shells in a variety of shapes and sizes, either by secreting a solid calcite shell or by cementing together grains that they pick up from the ocean floor. These organisms are particularly valuable microfossils because they are abundant, diverse, and morphologically distinct. Foraminifera also make useful biostratigraphic markers because most species are benthic (they live on the ocean floor). Unlike many planktonic organisms that float along ocean currents, such species remain geographically confined and form unique and local assemblages of fossils.

New and improved! Have another look at DNR’s landslide hazard website

There have been some important changes to our landslide hazard website since we last blogged about it on November 1, 2012. We have improved the resolution of the map by adding the National Weather Service (NWS) forecast zones. A shaded relief of elevation, along with the addition of salt and fresh water features, improves the look of the map, and makes it easier to locate the place(s) you may be interested in. Behind the scenes, an improved algorithm and the use of NWS precipitation forecasts makes the hazard level indicated on the map more closely relate to what is happening on the ground.

As was true before, the webpage is a test project of the DNR and NWS intended to raise awareness of shallow landslide hazards caused by periods of prolonged rainfall. The map is not intended to predict landslides at any particular time or location; it only rates the overall risk that one might occur, based on rainfall measurements over the past week and forecasts for the coming 48 hours.