322,882 research outputs found
Tsunami threat in the Indian Ocean from a future megathrust earthquake west of Sumatra
No full textAbstract not availableJohn McCloskey, Andrea Antonioli, Alessio Piatanesi, Kerry Sieh, Sandy Steacy, Suleyman Nalbant, Massimo Cocco, Carlo Giunchi, JianDong Huang, Paul Dunlo
Interseismic coupling, stress evolution, and earthquake slip on the Sunda megathrust
No full textThe extent to which interseismic coupling controls the slip distribution of large megathrust earthquakes is unclear, with some authors proposing that it is the primary control and others suggesting that stress changes from previous earthquakes are of first-order importance. Here, we develop a detailed stress history of the Sunda megathrust, modified by coupling, and compare the correlation between slip and stress with that of slip versus coupling. We find that the slip distributions of recent earthquakes are more consistent with the stress field than with the coupling distributions but observe that in places, the stress pattern is strongly dependent on poorly constrained values of slip in historical earthquakes. We also find that of the 13 earthquakes in our study for which we have hypocentral locations, only two appear to have nucleated in areas of negative stress, and these locations correspond to large uncertainties in the slip distribution of pre-instrumental events.Suleyman Nalbant, John McCloskey, Sandy Steacy, Mairead NicBhloscaidh, and Shane Murph
A Hybrid ETAS‐Coulomb Approach to Forecast Spatiotemporal Aftershock Rates
No full textAftershock sequences are an ideal testing ground for operational earthquake forecasting models as they contain relatively large numbers of earthquakes clustered in time and space. To date, most successful forecast models have been statistical, building on empirical observations of aftershock decay with time and earthquake size frequency distributions. Another approach is to include Coulomb stress changes from the mainshock which influence the spatial location of the aftershocks although these models have generally not performed as well as the statistical ones. Here we develop a new hybrid Epidemic‐Type Aftershock Sequence (ETAS)/Coulomb model which attempts to overcome the limitations of its predecessors by redistributing forecast rate from negatively to positively stressed regions based on observations in the model learning period of the percentage of events occurring in those positively stressed regions. We test this model against the 1992 Landers aftershock sequence using three different ETAS kernels and five different models for slip in the Landers earthquake. We also consider two variations of rate redistribution, one based on a fixed value and the other variable depending on the percentage of aftershocks observed in positively stressed Coulomb regions during the learning period. We find that the latter model performs at least as well as ETAS on its own in all tests and better than ETAS in 14 of 15 tests in which we forecast successive 24‐hr periods. Our results suggest that including Coulomb stress changes can improve operational earthquake forecasting models.T. Reverso, S. Steacy, D. Marsa
A tale of two disasters: biases in risk communication
No full textTheme for 2016: Recognizing and representing eventsRisk communication, where scientists inform policy-makers
or the populace of the probability and magnitude of possible
disasters, is essential to disaster management – enabling
people to make better decisions regarding preventative steps,
evacuations, etc. Psychological research, however, has
identified multiple biases that can affect people’s
interpretation of probabilities and thus risk. For example,
availability (Tversky & Kahneman, 1973) is known to
confound probability estimates while the descriptionexperience
gap (D-E Gap) (Hertwig & Erev, 2009) shows low
probability events being over-weighted when described and
under-weighted when learnt from laboratory tasks. This paper
examines how probability descriptions interact with real
world experience of events. Responses from 294 participants
across 8 conditions showed that people’s responses, given the
same described probabilities and consequences, were altered
by their familiarity with the disaster (bushfire vs earthquake)
and its salience to them personally. The implications of this
for risk communication are discussed.Matthew B. Welsh, Sandy Steacy, Steve H. Begg, Daniel J. Navarr
Diffusive author(s), cohesive author: Analysis of S/N (1994)
No full textThis study indicates the ways in which various aspects of the author(s) are brought forth in Dumb type’s performance art, the S/N production. Previous research has suggested a non-hierarchical organization of Dumb type and the absence of a “privileged author” in Dumb type’s collaborative work, S/N. However, the results that I have investigated from member’s interviews on the creative process of S/N along with my analysis of the recorded images of S/N, indicate a different aspect of the author(s). First, S/N was created through, so to speak, the collective ideas of the members of Dumb type. Further, S/N has at least nine quotations from previous performances, installations, and printed writings, besides the work-in-progress technique. Explicating one of the “author functions” as given by Michel Foucault, each text has plural subjects of the author. However, it has been revealed from members’ interviews that Teiji Furuhashi had a decision-making role in selecting the members’ ideas within the performance. Since then, S/N has had plural subjects of creation; however, Furuhashi is one of the subjects of creation along with the “privileged author.” S/N has plural authors (diffusive authors) yet at the same time, it has a “privileged author,” Teiji Furuhashi (cohesive author)
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Stress triggering and the Canterbury earthquake sequence
No full textThe Canterbury earthquake sequence, which includes the devastating Christchurch event of 2011 February, has to date led to losses of around 40 billion NZ dollars. The location and severity of the earthquakes was a surprise to most inhabitants as the seismic hazard model was dominated by an expected Mw > 8 earthquake on the Alpine fault and an Mw 7.5 earthquake on the Porters Pass fault, 150 and 80km to the west of Christchurch. The sequence to date has included an Mw = 7.1 earthquake and 3 Mw >/= 5.9 events which migrated from west to east. Here we investigate whether the later events are consistent with stress triggering and whether a simple stress map produced shortly after the first earthquake would have accurately indicated the regions where the subsequent activity occurred. We find that 100 percent of M > 5.5 earthquakes occurred in positive stress areas computed using a slip model for the first event that was available within 10 d of its occurrence. We further find that the stress changes at the starting points of major slip patches of post-Darfield main events are consistent with triggering although this is not always true at the hypocentral locations. Our results suggest that Coulomb stress changes contributed to the evolution of the Canterbury sequence and we note additional areas of increased stress in the Christchurch region and on the Porters Pass fault.Sandy Steacy, Abigail Jimenez and Caroline Holde
Author's address:
No full textCan archives of audiovisual TV interviews be used to make authors more visible to students, and thereby reduce the learning gap between native and non-native language speakers in college classes? We examined students in a college course who learned about one scholar's ideas through watching an audiovisual TV interview (i.e., visible author format) and about another scholar's ideas through reading a formal text description (i.e., invisible author format). For the invisible author, native language speakers scored significantly higher than the non-native language speakers on a corresponding exam question (i.e., a cognitive measure), generated more words on the exam question (i.e., a motivational measure), and mentioned the author's name more often in answering the exam question (i.e., an affective measure). For the visible author, the groups did not differ on any of these measures. These findings provide evidence for the idea that making the author visible through audiovisual TV interviews can eliminate the learning gap between native and non-native language speakers. 3 Universities around the world serve students who are non-native speakers of th
- …
