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Isolating active orogenic wedge deformation in the southern Subandes of Bolivia

A new GPS-derived surface velocity field for the central Andean backarc permits an assessment of orogenic wedge deformation across the southern Subandes of Bolivia, where recent studies suggest that great earthquakes (>Mw 8) are possible. We find that the backarc is not isolated from the main plate boundary seismic cycle. Rather, signals from subduction zone earthquakes contaminate the velocity field at distances greater than 800 km from the Chile trench. Two new wedge-crossing velocity profiles, corrected for seasonal and earthquake affects, reveal distinct regions that reflect (1) locking of the main plate boundary across the high Andes, (2) the location of and loading rate at the back of orogenic wedge, and (3) an east flank velocity gradient indicative of décollement locking beneath the Subandes. Modeling of the Subandean portions of the profiles indicates along-strike variations in the décollement locked width (WL) and wedge loading rate; the northern wedge décollement has a WL of ~100 km while accumulating slip at a rate of ~14 mm/yr, whereas the southern wedge has a WL of ~61 km and a slip rate of ~7 mm/yr. When compared to Quaternary estimates of geologic shortening and evidence for Holocene internal wedge deformation, the new GPS-derived wedge loading rates may indicate that the southern wedge is experiencing a phase of thickening via reactivation of preexisting internal structures. In contrast, we suspect that the northern wedge is undergoing an accretion or widening phase primarily via slip on relatively young thrust-front faults

Plant procedures, principles of information processing, and incorporation of DOE guidelines: A juggling act

Procedure format and style--the manner in which information is organized and visually presented to the procedure user--strongly influence procedure usability, and therefore influence safety and efficiency. The purpose of this paper is to describe recent and on-going efforts at the Rocky Flats Plant (RFP) to enhance plant procedures by applying established principles of human information processing in procedure development, and to educate plant personnel (especially those involved in procedure development) to the importance of these issues in maintaining safe and efficient operations

Human Factoring the Procedures Element in a Complex Manufacturing System

As a result of Human Factors evaluations of procedures associated with incidents at Rocky Flats Plant (RFP) it was determined that the existing procedure format created significant opportunities for confusion in their attempt to convey information about a work process. For instance, there was no mechanism to clearly identify the participants and their roles during the Instructions portion of the procedure. In addition, procedure authors frequently used complex logic to convey a series of contingent actions within steps. It was also difficult to discern the actual procedure steps from other types of information in the procedure. These and other inadequacies prompted the Human Factors Engineering (HFE) department to propose solutions to these problems that followed well-researched principles of cognitive psychology, dealing with how humans process information. Format and style contribute to procedure usability, and therefore to safety and efficiency in operations governed by the procedures. Since it was difficult to tie specific performance failures to specific format and style characteristics and thereby clearly define costs and benefits, it was difficult on that basis to sell the idea that changes in procedure format and style were really necessary to improve safety and efficiency. In addition, we found that the socio-political systems governing this process, particularly at the subprocess interface level, were not functioning efficiently. Both the technological aspects of the process and the socio-political aspects were contributing to waste and considerable re-work. Fixing the customer feedback loop to the process owners not only minimized re-work and waste, but also provided the data to persuade subprocess owners to make the necessary changes that heretofore were being met with great resistance. </jats:p

Human factoring the procedures element in a complex manufacturing system

As a result of Human Factors evaluations of procedures associated with incidents at Rocky Flats Plant (RFP) it was determined that the existing procedure format created significant opportunities for confusion in their attempt to convey information about a work process. For instance, there was no mechanism to clearly identify the participants and their roles during the instructions portion of the procedure. In addition, procedure authors frequently used complex logic to convey a series of contingent actions within steps. It was also difficult to discern the actual procedure steps from other types of information in the procedure. These and other inadequacies prompted the Human Factors Engineering (HFE) department to propose solutions to these problems that followed well-researched principles of cognitive psychology, dealing with how humans process information. Format and style contribute to procedure usability, and therefore to safety and efficiency in operations governed by the procedures. Since it was difficult to tie specific performance failures to specific format and style characteristics and thereby dearly define costs and benefits, it was difficult on that basis to sell the idea that changes in procedure format and style were really necessary to improve safety and efficiency. In addition, we found that the socio-political systems governing this process, particularly at the subprocess interface level, were not functioning efficiently. Both the technological aspects of the process and the socio-political aspects were contributing to waste and considerable re-work. Fixing the customer feedback loop to the process owners not only minimized re-work and waste, but also provided the data to persuade subprocess owners to make the necessary changes that heretofore were being met with great resistance