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5 results on '"HADDAD, AMANDA G."'

2. Estimating two-dimensional static stabilities and geomorphic settings of precariously balanced rocks from unconstrained digital photographs

Author

Haddad, David E., Zielke, Olaf, Arrowsmith, J. Ramon, Purvance, Matthew D., Haddad, Amanda G., and Landgraf, Angela

Subjects
Institut für Erd- und Umweltwissenschaften
Abstract

The need to accurately document the spatiotemporal distribution of earthquake-generated strong ground motions is essential for evaluating the seismic vulnerability of sites of critical infrastructure. Understanding the threshold for maximum earthquake-induced ground motions at such sites provides valuable information to seismologists, earthquake engineers, local agencies, and policymakers when determining ground motion hazards of seismically sensitive infrastructures. In this context, fragile geologic features such as precariously balanced rocks (PBRs) serve as negative evidence for earthquake-induced ground motions and provide important physical constraints on the upper limits of ground motions. The three-dimensional (3D) shape of a PBR is a critical factor in determining its static stability and thus susceptibility to toppling during strong ground shaking events. Furthermore, the geomorphic settings of PBRs provide important controls on PBR exhumation histories that are interpreted from surface exposure dating methods. In this paper, we present PBRslenderness, a MATLAB-based program that evaluates the two-dimensional (2D) static stabilities of PBRs from unconstrained digital photographs. The program's graphical user interface allows users to interactively digitize a PBR and calculates the 2D geometric parameters that define its static stability. A reproducibility study showed that our 2D calculations compare well against their counterparts that were computed in 3D (R-2 = 0.77-0.98 for 22 samples). A sensitivity study for single-user and multiuser digitization routines further confirmed the reproducibility of PBRslenderness estimates (coefficients of variation c(v) = 4.3%-6.5% for 100 runs; R-2 = 0.87-0.99 for 20 PBRs). We used PBRslenderness to analyze 261 PBRs in a low-seismicity setting to investigate the local geomorphic controls on PBR stability and preservation. PBRslenderness showed that a PBR's shape strongly controls its static stability and that there is no relationship between a PBR's stability and its geomorphic location in a drainage basin. However, the geomorphic settings of PBRs control their preservation potential by restricting their formation to hillslope gradients

Published
2012

4. THE CLASSROOM CONNECTION PROGRAM: BRINGING DEEP SEA RESEARCH TO STUDENTS OF ALL LEARNING LEVELS.

Author

HADDAD, AMANDA G., TURNER, MARY K., JOSEPH, CYNTHIA, ORCUTT, BETH N., and SAMUELSON, LINDA

Subjects
MARINE science education, OCEANOGRAPHY, STUDENTS with disabilities, LEARNING disabilities, LESSON planning
Abstract

SHIP-TO-CLASSROOM INTERACTIONS ARE INCREASINGLY COMMON ON SCIENTIFIC research cruises, as are other informal marine education outreach programs. However, very rarely (if at all) are the materials developed by these interactions and programs accessible to students with learning disabilities. These students often find the material "cool" and intriguing but are not able to do the activities or read the material posted for a number of reasons: their reading level is too low, their attention span is not long enough to read paragraphs of information, and/or they do not understand the concept being communicated. Building off of lessons learned in an earlier ship-toclassroom education program (Orcutt et al. 2011), we launched the Classroom Connection (CC) program to include students with all learning levels in education outreach efforts by creating accessible reading materials and modified hands-on, student-led activities. The CC program targeted elementary and middle school children with learning disabilities but it was open to students of alI ages and academic levels. Here, we present an overview of the CC program operated during two ocean research expeditions, highlighting steps taken to make material accessible to all classrooms. In particular, we address the importance of "accessible" lesson plans, measurable evaluation, and advance promotion of the program. It is our hope that the CC program becomes a widely used template for marine outreach and education as it is inclusive of all students regardless of their learning level. [ABSTRACT FROM AUTHOR]

Published
2012

5. Applications of airborne and terrestrial laser scanning to paleoseismology.

Author

Haddad, David E., Akçiz, Sinan O., Arrowsmith, J. Ramón, Rhodes, Dallas D., Oldow, John S., Zielke, Olaf, Toké, Nathan A., Haddad, Amanda G., Mauer, Juergen, and Shilpakar, Prabin

Subjects
*PALEOSEISMOLOGY, *EARTHQUAKES, *EARTHQUAKE prediction, *INDUSTRIAL lasers, *THREE-dimensional imaging
Abstract

Paleoseismic investigations aim to document past earthquake characteristics such as rupture location, frequency, distribution of slip, and ground shaking intensity-critical parameters for improved understanding of earthquake processes and refined earthquake forecasts. These investigations increasingly rely on high-resolution (<1 m) digital elevation models (DEMs) to measure earthquake-related ground deformation and perform process-oriented analyses. Three case studies demonstrate airborne and terrestrial laser scanning (ALS and TLS) for paleoseismic research. Case 1 illustrates rapid production of accurate, high-resolution, and georeferenced three-dimensional (3D) orthophotographs of stratigraphic and fault relationships in trench exposures. TLS scans reduced the preparation time of the trench and provided 3D visualization and reconstruction of strata, contacts, and permanent digital archival of the trench. Case 2 illustrates quantifi cation of fault scarp degradation rates using repeat topographic surveys. The topographic surveys of the scarps formed in the 1992 Landers (California) earthquake documented the centimeter-scale erosional landforms developed by repeated winter storm-driven erosion, particularly in narrow channels crossing the surface rupture. Vertical and headward incision rates of channels were as much as ~6.25 cm/yr and ~62.5 cm/yr, respectively. Case 3 illustrates characterization of the 3D shape and geomorphic setting of precariously balanced rocks (PBRs) that serve as negative indicators for strong ground motions. Landscape morphometry computed from ALS-derived DEMs showed that PBRs are preserved on hillslope angles between 10° and 40° and contributing areas (per unit contour length) between 5 and 30 m2/m. This situation refi nes interpretations of PBR exhumation rates and thus their effectiveness as paleoseismometers. Given that earthquakes disrupt Earth's surface at centimeter to meter scales and that depositional and erosional responses typically operate on similar scales, ALS and TLS provide the absolute measurement capability suffi cient to characterize these changes in challenging geometric arrangements, and thus demonstrate their value as effective analytical tools in paleoseismology. [ABSTRACT FROM AUTHOR]

Published
2012
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