Crooked Line Research Articles

Simultaneous estimation of residual static and crossdip corrections

Seismic surveys on land are frequently conducted along nonlinear survey lines. Familiar examples include crooked lines controlled by existing road networks or by surface typography, lines that are otherwise linear but along which shotpoints occasionally must be offset laterally, and intentionally designed three‐dimensional (3-D) or broad‐line surveys. Departures from linear profiles introduce an element of complexity—crossdip—into the problem of estimating residual near‐surface reflection static time corrections (statics). Crossdip is the component of dip normal to the local profile direction. We have incorporated the effect of crossdip into the system of simultaneous equations that model residual static anomalies. The observed traveltimes of all reflections selected for analysis are represented as linear combinations of source and receiver static anomalies, structural shapes, residual normal moveouts, and crossdip terms. The static time components are taken to be surface‐consistent and independent of reflecting horizon, whereas the other solution parameters are subsurface‐consistent and pertain to specific horizons. Unfortunately, the inclusion of crossdip in the equations increases the degree of nonuniqueness of residual statics solutions. Its inclusion, however, is a necessity wherever horizons having differing crossdips are analyzed simultaneously. Such simultaneous analysis often is the best means for upgrading the reliability of the crosscorrelation estimates (i.e., the traveltime observations) upon which all statics are based. Synthetic‐data examples demonstrate the degree to which crossdip estimates and statics estimates can be separated from one another. Although estimates of crossdips are a useful by‐product, the accuracy of the static corrections is considered of prime importance. When critical crossdip terms are ignored in a statics solution, the quality of the common‐depthpoint (CDP) stacks suffer, as shown in comparison processings of field sections. Moreover, crossdip estimates from 3-D or broad‐line surveys are questionable if crossdip and static corrections are not considered in a unified solution.

TRANSFORMATION OF DIPOLE SOUNDINGS OBTAINED ALONG A CROOKED LINE *

AbstractData collected in a dipole‐dipole sounding along a crooked line can be transformed to form an approximately equivalent Schlumberger sounding, using a simple matrix inversion technique. The equivalent curve can be interpreted using rapid interpretation methods.

The Literary Uses of a Proverb

TEN years ago there was a brief flurry of notes on the provenience of the proverb 'Deus escreve direito por linhas tortas,' rendered in English as 'God writes straight with crooked lines.' Tradition attributes this proverb to the Portuguese, but discussion of it at the time centred on the possibility that its ultimate source was St Augustine. The controversy ended inconclusively. The suggestion that the proverb derives from Augustine was based on a puzzling entry in Burton Stevenson's Home Book ofProverbs, Maxims and Familiar Phrases (Macmillan: New York, 1948; p. 969). Stevenson misleads by associating the proverb with Augustine: 'St. Augustine, Apothegm (C. AD 400) [-] A Portuguese proverb, quoted by Paul Claudel as the theme of his play, The Satin Slipper (1931).' Stevenson's error appears to have sprouted from a rather careless reading of Claudel's epigraphic use in Le Soulier de Satin of the proverb, which he clearly labels as Portuguese, in tandem with a quotation-'Etiam peccata' ('Even sins')-which he just as clearly attributes to Augustine. Claudel's application of the proverb remains its best known literary use. Virtually unknown, however, are two contemporary American uses. Interestingly enough, the Americans are, like Claudel, Roman Catholics, and both of them employ the proverb to illustrate and to support accounts of spiritual conversion-one in a series of closely related autobiographical poems, the other in a novel about a Catholic cleric. The writers in question are J. F. Powers (1917) and William O. Everson (1912); the latter, a one-time lay brother in the Dominican Order, is better known as Brother Antoninus.2 Fifteen years ago Brother Antoninus published a collection of poems written in a five-year period, beginning in 1949. Published as The Crooked Lines of God (University of Detroit Press, 1959), these poems are organized into three discrete series, each of which records, in the author's words, 'a particular phase of spiritual development'. The book bears as its epigraph the Portuguese proverb that provided his title. How much this proverb meant to Brother Antoninus and just how essential it was to his understanding of the purpose of his spiritual odyssey is revealed in a thematic foreword. 'These Crooked Lines,' as he calls it, opens with this paragraph:

Needed for Liberalism: A New Metaphysics and a New Program

THESE are generally conceded to be dark days for liberals. The The peoples of the world, now rather loosely divided into two great opposing groups, are being dominated increasingly by ideological extremes. One large group is already in bondage to totalitarianism. In the other group, the impulses to totalitarianism are active and strong. The liberal, being moderate in tendency, is caught in between. As he is cuffed by the bears of the Left, he is being gored by the bulls of the Right. Both would level down the freedom for which he stands to a narrow and crooked line of action, and a narrow and crooked line of thought. The liberal should not be surprised at this. His inveterate effort is to maintain a reasonable position and a middle course. Inevitably this subjects him to double exposure. To the nearsighted hatchet men of the Right, he can only seem over on the Left, a dupe, pinko, or fronter. To the mechanically minded men of the Left, he must belong dialectically to the Right, to the soft decadent outer crust of a diseased and dying civilization. In our tense and angry world, inevitable as this dilemma is, it is also extremely dangerous for the liberal. It invites enmity from two directions, indeed, from the two really strong and opposite entrenchments facing each other today. The question naturally arises: Is not this a time for the liberal to duck, to let the big boys go at each other alone, and cut each other down? Can liberalism

The recent formations and glacial phenomena of Strathnairn

Subject of Paper. The paper read by Mr Wallace before this Society, in February 1879, gave an account of the rock formations of the Strathnairn district. The intention of this paper (which may be considered as a supplement to Mr Wallace’s) is to give some account of the boulder-clay, gravels, and other recent formations found overlying the Gneiss and Old Red Sandstone, and of the extraordinary evidences of glacial denudation exhibited by the rocks and boulders. Description of District. The River Nairn flows in a due north-easterly direction. Its drainage area is 30 miles long and from 2 to 7½ miles wide, the narrowest point being at the parish church of Daviot, about midway between the source of the river and the sea. It will be well to note, at the outset, the position of the church of Daviot on the map, as it forms a convenient point for reference. On the east side of the river, and opposite the Daviot church, is the Craggie Burn, and 4 miles south-east of Craggie is Loch Moy, both of which will be afterwards mentioned. The watershed between the Nairn and the Findhorn runs in a crooked line along a range of high, smooth-topped, and heath-covered mountains of gneiss and granite rocks, from Carn-nan-tri-Tighearnan, 2013 feet high, at the source of the Cawdor Burn, to Carn Ghriogair, 2637 feet high, at the extreme source of the Nairn. The three lowest points or gaps in this watershed are,—(1) the opening above Craggie, through which