1855 and 1991 Surveys of the San Andreas Fault: Implications for Fault Mechanics

Two monuments from an 1855 cadastral survey that span the San Andreas fault in the Carrizo Plain have been right-laterally displaced 11.0 ± 2.5 m by the 1857 Fort Tejon earthquake and associated seismicity and afterslip. This measurement confirms that at least 9.5 ± 0.5 m of slip occurred along the main fault trace, as suggested by measurements of offset channels near Wallace Creek. The slip varied by 2 to 3 m along a 2.6-km section of the main fault trace. Using radiocarbon dates of the penultimate large earthquake and measurements of slip from the 1857 earthquake, we calculate an apparent slip rate for the last complete earthquake cycle that is at least 25% lower than the late-Holocene slip rate on the main fault trace. Comparison of short-term broad-aperture strain accumulation rates with the narrow-aperture late-Holocene slip rate indicates that the fault behaves nearly elastically over a time scale of several earthquake cycles. Therefore, slip in future earthquakes should compensate the slip-rate deficit from the 1857 earthquake

Global Seismic Nowcasting With Shannon Information Entropy.

Seismic nowcasting uses counts of small earthquakes as proxy data to estimate the current dynamical state of an earthquake fault system. The result is an earthquake potential score that characterizes the current state of progress of a defined geographic region through its nominal earthquake "cycle." The count of small earthquakes since the last large earthquake is the natural time that has elapsed since the last large earthquake (Varotsos et al., 2006, https://doi.org/10.1103/PhysRevE.74.021123). In addition to natural time, earthquake sequences can also be analyzed using Shannon information entropy ("information"), an idea that was pioneered by Shannon (1948, https://doi.org/10.1002/j.1538-7305.1948.tb01338.x). As a first step to add seismic information entropy into the nowcasting method, we incorporate magnitude information into the natural time counts by using event self-information. We find in this first application of seismic information entropy that the earthquake potential score values are similar to the values using only natural time. However, other characteristics of earthquake sequences, including the interevent time intervals, or the departure of higher magnitude events from the magnitude-frequency scaling line, may contain additional information

Knowledge Diffusion in R&D Groups: The Impact of Internet Technologies

判型：B5，昭和55年7月12

Knowledge Diffusion in R&D Groups: The Impact of Internet Technologies

Knowledge flows are the lifeblood of any R&D organisation. These firms are increasingly discovering that the knowledge they require is often located beyond their boundaries. In this paper, we investigate how R&D groups acquire and diffuse external knowledge and the role Internet technologies play in this process. The focus of our study is on the technological gatekeeper. Previous studies have found that gatekeepers are key nodes in the innovation process. These sporadic individuals have the skills to identify useful knowledge outside the firm and disseminate this among their local colleagues. However, much of the seminal gatekeeper research has been conducted over two decades ago. In the time since, there have been huge advances in ICT and especially Internet technologies. These technologies have dramatically altered how knowledge workers source and share their information. Our objective is to advance the gatekeeper theory into an era where the knowledge worker is saturated with information. Using case study methods, we examine knowledge flows in the R&D group of an Irish medical devices firm. Our results indicate that due to advances in Internet technology, the traditional gatekeeper no longer exists to any great extent. Instead, the modern R&D lab acquires and diffuses external knowledge through a combination of a ‘web gatekeeper’ and a ‘knowledge transformer.

Parental Co‐Construction of 5‐ to 13‐Year‐Olds\u27 Global Self‐Esteem Through Reminiscing About Past Events

The current study explored parental processes associated with children\u27s global self‐esteem development. Eighty 5‐ to 13‐year‐olds and one of their parents provided qualitative and quantitative data through questionnaires, open‐ended questions, and a laboratory‐based reminiscing task. Parents who included more explanations of emotions when writing about the lowest points in their lives were more likely to discuss explanations of emotions experienced in negative past events with their child, which was associated with child attachment security. Attachment was associated with concurrent self‐esteem, which predicted relative increases in self‐esteem 16 months later, on average. Finally, parent support also predicted residual increases in self‐esteem. Findings extend prior research by including younger ages and uncovering a process by which two theoretically relevant parenting behaviors impact self‐esteem development

Gutenberg-Richter statistics in topologically realistic system-level earthquake stress-evolution simulations

We discuss the problem of earthquake forecasting in the context of new models for the dynamics based on statistical physics. Here we focus on new, topologically realistic system-level approaches to the modeling of earthquake faults. We show that the frictional failure physics of earthquakes in these complex, topologically realistic models leads to self-organization of the statistical dynamics, and produces statistical distributions characterizing the activity, notably the Gutenberg-Richter magnitude frequency distribution, that are similar to those observed in nature. In particular, we show that a parameterization of friction that includes a simple representation of a dynamic stress intensity factor is needed to organize the dynamics. We also show that the slip distributions for synthetic events obtained in the model are also similar to those observed in nature

Panel: Going Virtual: Are there Real Opportunities for Business in Virtual Worlds?

Summary of Panel Topic (related to ICIS track theme on Social Networking

Systematic procedural and sensitivity analysis of the pattern informatics method for forecasting large (M > 5) earthquake events in southern California

Recent studies in the literature have introduced a new approach to earthquake forecasting based on representing the space-time patterns of localized seismicity by a time-dependent system state vector in a real-valued Hilbert space and deducing information about future space-time fluctuations from the phase angle of the state vector. While the success rate of this Pattern Informatics (PI) method has been encouraging, the method is still in its infancy. Procedural analysis, statistical testing, parameter sensitivity investigation and optimization all still need to be performed. In this paper, we attempt to optimize the PI approach by developing quantitative values for "predictive goodness" and analyzing possible variations in the proposed procedure. In addition, we attempt to quantify the systematic dependence on the quality of the input catalog of historic data and develop methods for combining catalogs from regions of different seismic rates.Comment: 39 pages, 4 tables, 9 figures. Submitted to Pure and Applied Geophysics on 30 November 200