Southern San Andreas Fault Evaluation Field Activity: Approaches to Measuring Small Geomorphic Offsets--Challenges and Recommendations for Active Fault Studies

Recovering paleoearthquake slip record in a highly dynamic alluvial and tectonic region (Hope Fault, New Zealand) from airborne lidar

“…Seismic hazard assessment requires properly anticipating the principal characteristics of the forthcoming large earthquakes, especially their expected magnitude or maximum coseismic slip and their recurrence time. One approach to estimate the awaited slip quantities of a forthcoming seismic event on a fault is to analyze the large earthquakes that broke the fault in the prehistorical time (i.e., paleoearthquakes) and to search whether the displacements they produced at the ground surface are still preserved and measurable in the morphology [e.g., Peltzer et al , ; Yeats and Prentice , ; McCalpin , , ; Tapponnier et al , ; Gold and Cowgill , ; Li et al , ; Zielke et al , ; Scharer et al , ]. This is not an easy task however, for several reasons [e.g., McCalpin , ; Scharer et al , ].…”

“…One approach to estimate the awaited slip quantities of a forthcoming seismic event on a fault is to analyze the large earthquakes that broke the fault in the prehistorical time (i.e., paleoearthquakes) and to search whether the displacements they produced at the ground surface are still preserved and measurable in the morphology [e.g., Peltzer et al , ; Yeats and Prentice , ; McCalpin , , ; Tapponnier et al , ; Gold and Cowgill , ; Li et al , ; Zielke et al , ; Scharer et al , ]. This is not an easy task however, for several reasons [e.g., McCalpin , ; Scharer et al , ]. Commonly, the landforms that best act as strain markers and strain recorders, especially along strike‐slip faults, are fluvial and alluvial landforms [e.g., Wallace , ; Sieh , ; Gaudemer et al , ; McGill and Sieh , ; McCalpin , , ; Arrowsmith and Zielke , ; Zielke et al , , ].…”

“Use of 3D Point Clouds in Geohazards” Special Issue: Current Challenges and Future Trends

“…More recently, the use of high-resolution three-dimensional datasets is providing new perspectives for the quantification of these low amplitude features along both fast-moving and slow slip-rate faults [40][41][42]. Unfortunately, there was no standard methodologies to rate the quality of the lateral offsets up until very recently and a certain ambiguity could have affected these studies, as was pointed out by Ferrater et al [13], in this Special Issue.…”

Lateral Offset Quality Rating along Low Slip Rate Faults: Application to the Alhama de Murcia Fault (SE Iberian Peninsula)

“…In that sense, experts tend to interpret geological data according to their expertise and previous knowledge (conceptual uncertainty) and they may not show a high confidence about their interpretations. Salisbury et al [4], Scharer et al [16], Salisbury et al [17] and Bond et al [38] propose that the results are better when more techniques are used to approach the problem (multiple approaches to measurement both remotely and in the field in the offset landform case). Relationship between offset and uncertainty for the 138 offsets measured along the Alhama de Murcia fault.…”

“…It is necessary to make a distinction between the measurement uncertainty and its quality. Aleatory uncertainty is that associated with the measurement process itself, whereas the epistemic uncertainty describes the degree of ambiguity in the interpretation of the offset history of the feature [16,17]. There is no standard methodology to rate the quality of offset landforms (largely ascribed to epistemic uncertainty).…”