Debris flow magnitudes: a global catalog

The episodic occurrence of debris flow events in response to stochastic precipitation and wildfire events makes hazard prediction challenging. Previous work has shown that frequency-magnitude distributions of non-fire-related debris flows follow a power law, but less is known about the distribution of post-fire debris flows. As a first step in parameterizing hazard models, we use frequency-magnitude distributions and cumulative distribution functions to compare volumes of post-fire debris flows to non-fire-related debris flows. Due to the large number of events required to parameterize frequency-magnitude distributions, and the relatively small number of post-fire event magnitudes recorded in the literature, we collected data on 73 recent post-fire events in the field. The resulting catalog of 988 debris flow events is presented as an appendix to this article. We found that the empirical cumulative distribution function of post-fire debris flow volumes is composed of smaller events than that of non-fire-related debris flows. In addition, the slope of the frequency-magnitude distribution of post-fire debris flows is steeper than that of non-fire-related debris flows, evidence that differences in the post-fire environment tend to produce a higher proportion of small events. We propose two possible explanations: 1) post-fire events occur on shorter return intervals than debris flows in similar basins that do not experience fire, causing their distribution to shift toward smaller events due to limitations in sediment supply, or 2) fire causes changes in resisting and driving forces on a package of sediment, such that a smaller perturbation of the system is required in order for a debris flow to occur, resulting in smaller event volumes.

Harpers Ferry, West Virginia, and vicinity, 1862 (Raster Image)

This layer is a georeferenced raster image of the untitled historic paper manuscript map: [Map of the country between Harpers Ferry and Leesburg, 1862]. It was sketched by Union General John White Geary, Oct. 21st, 1862. Scale not given. Covers Harpers Ferry region, West Virginia, including portions of Loudoun County, Virginia, Frederick and Washington Counties, Maryland, and Jefferson County, West Virginia. The image inside the map neatline is georeferenced to the surface of the earth and fit to the Virginia State Plane North Coordinate System (in Meters) (Fipszone 4501). All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, or other information associated with the principal map. This map shows features such as roads, towns and villages, drainage, and more. Relief shown by form lines. This layer is part of a selection of digitally scanned and georeferenced historic maps of the Civil War from the Harvard Map Collection. Many items from this selection are from a collection of maps deposited by the Military Order of the Loyal Legion of the United States Commandery of the State of Massachusetts (MOLLUS) in the Harvard Map Collection in 1938. These maps typically portray both natural and manmade features, in particular showing places of military importance. The selection represents a range of regions, originators, ground condition dates, scales, and purposes.

Battle of Cold Harbor, Virginia and vicinity, 1864 (Raster Image)

This layer is a georeferenced raster image of the untitled historic paper manuscript map: [Map of the Battle of Cold Harbor, Virginia and vicinity]. Scale not given. Covers a portion of Hanover County, Virginia, showing features in the region surrounding the Cold Harbor Battlefield, Virginia, 1864. The image inside the map neatline is georeferenced to the surface of the earth and fit to the Virginia State Plane South Coordinate System (in Meters) (Fipszone 4502). All map collar and inset information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, or other information associated with the principal map. This map shows features such as roads, towns and villages, drainage, dwellings with names of inhabitants, troop locations with dates, and more. This layer is part of a selection of digitally scanned and georeferenced historic maps of the Civil War from the Harvard Map Collection. Many items from this selection are from a collection of maps deposited by the Military Order of the Loyal Legion of the United States Commandery of the State of Massachusetts (MOLLUS) in the Harvard Map Collection in 1938. These maps typically portray both natural and manmade features, in particular showing places of military importance. The selection represents a range of regions, originators, ground condition dates, scales, and purposes.

Journal of the ... annual convention, Diocese of Virginia.

Title varies slightly.

The Virginia seminary magazine.

"Published under the supervision of the faculty of the Theological Seminary of Virginia."

A memoir of a portion of the Bolling family in England and Virginia.

Introduction signed: T.H.W. [i.e. Thomas H. Wynne]

Remarks on a pamphlet concerning the canon on lay discipline, passed at the recent Convention of Virginia, held in Alexandria, May, 1850.

Mode of access: Internet.

Thermal Imaging Applications In Urban Deer Control

Control of burgeoning populations of white-tailed deer (Odocoileus virginianus) is a challenging endeavor under the best of circumstances. The challenge is further complicated when control programs are attempted within an urban or suburban area. Wildlife managers often consider management techniques and equipment which have a proven track record. New challenges require new and innovative techniques. The deer management program in Fairfax County, Virginia has employed thermal imaging technology in a variety of ways to better address these unique challenges. In addition to the more commonly used aircraft-mounted FLIR (forward looking infrared), this program utilizes vehicle-mounted and hand-held thermal imaging devices. Thermal imaging is used in determining herd densities, ensuring that control areas are free of humans, locating deer, assessing target attributes and recovering culled deer. These devices bring a higher level of safety, efficiency and efficacy to control programs operating within these difficult environs.

Letters and legal opinion, 1798-1823

Legal opinion on an equity case (1798). Four letters to an unnamed correspondent (1801) regarding a shipment of papers; Joseph Hopkinson, member of Congress (1817) regarding a judiciary bill; a note (1818) to the cashier of the Bank of Columbia; and to Charles T. Mercer (1823) regarding property in Loudoun County, Virginia. Folder also contains newspaper clippings (ca. 1830-1842) regarding Washington's life and career, including one taken from the Journal of Law.

Grant, 1778, November 18

Grant of 38 acres of land in Culpeper County, Virginia, by Thomas, lord Fairfax, baron Cameron, "proprietor of the northern neck of Virginia," to Philip Pendleton. Issued in Frederick County, Virginia.

Eine Verhandlung : von der äusserlichen Wasser-Taufe, und Erklärung einiger Irrthümer, wie auch von der Feuer-Taufe und wie in Christo das gesetzliche Osterlamm aufgehöret, und das Abendmahl eingesetzt, und wie man den Geist Gottes erkennen soll von den Geistern des Irrthums /

Mode of access: Internet.

Historical sketches and reminiscences of an octogenarian.

Sketches of Washington County, Virginia, including an account of the Preston family.

Religious pamphlets

A collection of miscellaneous pamphlets on religion.

Journal of the annual council.

Mode of access: Internet.

Land ownership map: 1669-1796.

Scale ca. 1:14,400.