Historical accounts of earthquakes show a high degree of spatial variability and uncertainty associated with ground motion. For this reason, historical data are not often used as input for earthquake hazard assessment. Regionally, however, earthquake ground motion is related by the concept of attenuation. Seismic hazard assessment techniques usually rely on catalogues of earthquake epicenters together with empirical attenuation relationships to define the seismic hazard for a particular region. Such techniques, however, overlook local variations in ground motion associated with actual earthquakes. A technique for seismic hazard assessment that includes historical data using the theory of regionalized variables and linear estimation techniques best represents ground motion dichotomy. Modified Mercalli intensity observations for the period 1930 through 1971 were treated as regionalized variables to define the seismic hazard for a region of Southern California centered around San Fernando. Despite variations in construction quality and individual sensitivity to ground motion, intensity values associated with seventy percent of the earthquakes that occurred during this period, for which at least five intensity observations were recorded, were accurately treated as regionalized variables. A Gumbel analysis computed using spatially regular data sets developed from these intensity values precisely associated high hazard regions with active faults near San Fernando. Other earthquake ground motion data can also be treated, accurately, as regionalized variables. These data include peak instrument recordings of spectral acceleration, velocity, and displacement. Moreover, response to earthquake ground motion at discrete frequencies, as recorded by response spectra, is also regionalized. These data, therefore, are accurately estimated using kriging. Fundamentally, because earthquake ground motion is shown to be a regionalized variable, all aspects of regionalized variables theory are applicable for these data, including disjunctive kriging, conditional simulation, and co-kriging.

Two projects are documented within this MEM Report: I. The first project examined what was learnt involving the critical infrastructure in the aftermath of natural disasters in the Canterbury region of New Zealand – the most prominent being the series of earthquakes between 2010 and 2011. The project identified several learning gaps, leading to recommendations for further investigations that could add significant value for the lifeline infrastructure community. II. Following the Lifeline Lesson Learnt Project, the Disaster Mitigation Guideline series was initiated with two booklets, one on Emergency Potable Water and a second on Emergency Sanitation. The key message from both projects is that we can and must learn from disasters. The projects described are part of the emergency management, and critical infrastructure learning cycles – presenting knowledge captured by others in a digestible format, enabling the lessons to be reapplied. Without these kinds of projects, there will be fewer opportunities to learn from other’s successes and failures when it comes to preparing for natural disasters.

In this thesis, I use multiple techniques to investigate the active faulting and deformation of the Altay Mountains, Western Mongolia. The Altay are an intracontinental transpressional mountain range, which are deforming in the far-field of the India-Asia collision. An anastomosing network of dextral faults strikes NNW-SSE, and accommodates NE-SW oriented shortening by rotating anticlockwise about vertical axes. I begin by characterising the Altay faults, and add to what is already known about their surface expression with new observations of active faulting and three previously undescribed ancient earthquake ruptures. I use ¹⁰Be cosmogenic dating and uranium-series dating on pedogenic carbonate to estimate the average Quaternary rate of slip for two of the major fault zones in the Altay. The slip rate on the Ölgiy fault is constrained to 0.3-2.1 mm/yr^-1. Results from the Hovd fault are ambiguous, demonstrating the complications encountered with application of Quaternary dating techniques. I measure palaeomagnetic directions from Cretaceous to Pliocene-aged sediments in the eastern Altay to constrain the degree of anticlockwise rotation. Results from thermal demagnetisation of specimens indicate that the eastern Altay has not undergone significant rotation, in contrast with previous studies from the Siberian Altay that reveal almost 40 degrees of anticlockwise rotation. This suggests that the eastern-most Altay fault is too young to have experienced significant rotation, or is kinematically different from the Siberian Altay. I apply apatite fission track (AFT) dating and track length modeling to the central Altay. Results from AFT dating show rapid cooling in the late Cretaceous due to the distal assembly of Central Asia, suggesting that there was pre-existing topography at the start of the Late Cenozoic phase of deformation, the timing of which is constrained to have initiated at least 20 Myr ago. My work demonstrates that combining results from techniques that cover a variety of time scales quantifies the evolution of active faulting and deformation in the region.

In this thesis I use Interferometric Synthetic Aperture Radar (InSAR) and GPS geodetic observations, along with numerical models, to examine the distribution of strain, assess seismic hazard, and study the dynamics of deformation across Turkey and Iran. I measure interseismic strain accumulation across the Ashkabad fault using InSAR, and find that atmospheric corrections using MERIS (Medium Resolution Imaging Spectrometer) data are necessary in order to retrieve the tectonic signal in the presence of large atmospheric delays. I estimate a slip rate of 5-12 mm/yr for the Ashkabad fault which is faster than previous geodetic estimates. I also attempt to validate atmospheric corrections derived from the ERA-Interim numerical weather model and find that they do not work satisfactorily for this region. I produce InSAR-derived velocity maps for five overlapping tracks in Eastern Turkey, covering both the North Anatolian Fault (NAF) and East Anatolian Fault (EAF), and measure slip rates for the NAF and EAF of 20+/-3 mm/yr and 10+/-2 mm/yr respectively. I calculate a velocity field for Eastern Turkey from these InSAR data and a compilation of GPS data, and find that strain is mainly localised across the NAF and EAF and that there is negligible differential vertical motion across the Anatolian Plateau. I construct a thin viscous sheet model for Iran and find that the GPS velocity field is well described by deformation of a ductile lithosphere. Contrary to previous suggestions, a rigid central Iran is not required to match the kinematics of Iranian deformation, but buoyancy forces acting in the lithosphere are found to play an important role. I develop a new method to assess slip rates and therefore seismic hazard on major faults in Iran from this continuum model. In this thesis I have measured slip rates across three major strike-slip faults using InSAR; the first time this has been achieved for the Ashkabad fault and the EAF. I have demonstrated the importance of atmospheric correction for these results, and have shown that Iran deforms as a continuous medium.

Over the past few decades, remote sensing has emerged as a powerful tool for studying active faulting in continental regions. However, the commonly used remote sensing techniques, including radar interferometry, visual inspection of imagery, and image matching, cannot measure three-dimensional (3D) surface displacements in earthquakes, limiting our ability to investigate faulting. The improvement of very high-resolution (VHR) optical imaging systems (stereo in particular) in recent years has made it possible for earth scientists to measure 3D surface deformation remotely. In this thesis, I contribute to assessing the capability of VHR optical imagery, by determining earthquake deformation from four different types of earthquakes (different in sense of slip and date of the event). In the case of the 2010 M_w 7.2 El Mayor-Cucapah, Mexico earthquake, I show that digital elevation models (DEMs) derived from Pleiades stereo imagery are comparable to light detection and ranging (LiDAR) surveys, and differencing pre- and post-earthquake DEMs can measure 3D displacements, which will be very useful for studying future earthquakes. For the 2013 M_w 7.7 Balochistan, Pakistan earthquake, I determine the vertical motion from a post-earthquake Pleiades DEM and find constant fault kinematics throughout the Late Quaternary. This study has resolved a current controversy of the Balochistan earthquake, in which it has been argued that kinematics of the Hoshab fault switches between strike-slip and dip-slip. Applying historical aerial, KH-9 Hexagon spy satellite, SPOT-2 and modern SPOT-6 images to the 1978 M_w 7.3 Tabas-e-Golshan earthquake, I measure the coseismic and postseismic displacements, and show that the Tabas fold system in eastern Iran may exhibit characteristic slip behaviour. Combining Pleiades imagery, fieldwork and geological dating techniques, I determine slip in the 1556 Huaxian earthquake in China and the recurrence interval for similar events. These examples demonstrate the usefulness of high-resolution optical imagery in investigating past and present earthquakes.

This dissertation explores the capability of dense seismic array data for imaging the rupture properties of earthquake sources using a method known as back-projection. Only within the past 10 or 15 years has implementation of the method become feasible through the development of large aperture seismic arrays such as the High Sensitivity Seismograph Network in Japan and the Transportable Array in the United States. Coincidentally, this buildup in data coverage has also been accompanied by a global cluster of giant earthquakes (Mw>8.0). Much of the material in this thesis is devoted to imaging the source complexity of these large events. In particular, evidence for rupture segmentation, dynamic triggering, and frequency dependent energy release is presented. These observations have substantial implications for evaluating the seismic and tsunami hazards of future large earthquakes. In many cases, the details of the large ruptures can only be imaged by the back-projection method through the addition of different data sets and incorporating additional processing steps that enhance low-amplitude signals. These improvements to resolution can also be utilized to study much smaller events. This approach is taken for studying two very different types of earthquakes. First, a global study of the enigmatic intermediate-depth (100-300 km) earthquakes is performed. The results show that these events commonly have sub-horizontal rupture planes and suggest dynamic triggering of multiple sub-events. From these observations, a hypothesis for the generation of intermediate-depth events is proposed. Second, the early aftershock sequences of the 2004 Mw 9.1 Sumatra-Andaman and 2011 Mw 9.0 Tohoku, Japan earthquakes are studied using the back-projection method. These analyses show that many events can be detected that are not in any local or global earthquake catalogues. In particular, the locations of aftershocks in the back-projection results of the 2011 Tohoku sequence fill in gaps in the aftershock distribution of the Japan Meteorological Agency catalogue. These results may change inferences of the behavior of the 2011 mainshock, as well as the nature of future seismicity in this region. In addition, the rupture areas of the largest aftershocks can be determined, and compared to the rupture area of the mainshock. For the Tohoku event, this comparison reveals that the aftershocks contribute significantly to the cumulative failure area of the subduction interface. This result implies that future megathrust events in this region can have larger magnitudes than the 2011 event. / Earth and Planetary Sciences

The Reno-Sparks community is in a seismically hazardous area. Recent research indicates that a Richter 7.0 or greater magnitude earthquake could affect the area. Many of the emergency and essential facilities are situated in dangerous geological locations and are housed in outdated structures which could be severely damaged in the event of a major earthquake. Detailed site evaluations need to be made with respect to location of new structures and of existing building safety. The 1979 Unified Building Code seismic provisions should be adopted without exception; Nevada Revised Statute 278 .160 needs to be revised to require a seismic safety plan; Alquist-Priolo legislation should be implemented, and creation of a comprehensive civil defense plan for seismic hazards is essential.

Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Earth and Planetary Sciences, 1979. / Microfiche copy available in Archives and Science. / Vita. / Includes bibliographies. / by Wang-Ping Chen. / Ph.D.

Τα τελευταία χρόνια, τόσο στη διεθνή όσο και στην ελληνική επιστημονική κοινότητα, παρατηρείται ένα αυξημένο ενδιαφέρον για το πώς η σκέψη των μικρών παιδιών προσεγγίζει το φυσικό κόσμο. Έτσι το πεδίο έρευνας των Φυσικών Επιστημών επικεντρώνεται στην ανίχνευση και μελέτη των βιωματικών παραστάσεων των παιδιών (Ραβάνης, 1999). Η ανίχνευση και η καταγραφή αυτών των παραστάσεων θεωρείται σημαντική, καθώς είναι παρούσες στη σκέψη των παιδιών και αποτελούν εμπόδια για την κατανόηση των επιστημονικών εννοιών και φαινομένων (Baster, 1995, Sharp, 1995). Αυτή η έρευνα διεξήχθη για να τεθεί ένα γενικότερος προβληματισμός ως προς τις σκέψεις των παιδιών της προσχολικής ηλικίας, για ένα γεωλογικό φαινόμενο που ταράσσει συχνά τον ελλαδικό χώρο, τον σεισμό, καθώς και για να διαπιστωθεί αν τα παιδιά της συγκεκριμένης ηλικίας μπορούν να ανταπεξέρθουν επαρκώς ως προς την πρόληψη και αντιμετώπιση αυτού του φαινομένου. Έτσι, επιχειρήθηκε η ανίχνευση των νοητικών παραστάσεων των παιδιών προσχολικής ηλικίας σχετικά με τη γεωφυσικά χαρακτηριστικά της γης, για να εμβαθύνει στη συνέχεια στο φαινόμενο του σεισμού καθώς και στην πρόληψη και αντιμετώπισή του. Αρχικά, παρουσιάζεται το θεωρητικό πλαίσιο με βάση το οποίο σχεδιάστηκε η παρούσα έρευνα και φυσικά τα πορίσματα ερευνών που έχουν διεξαχθεί σχετικά με το υπό εξέταση θέμα. Εν συνεχεία, γίνεται αναφορά στο μεθοδολογία της συγκεκριμένη έρευνα και παρουσιάζονται τα αποτελέσματα, τόσο σε κάθε φάση της ανίχνευσης όσο και συνολικά. Τέλος, ο σχολιασμός των αποτελεσμάτων, τα συμπεράσματα και η συζήτηση καθώς και οι επιπτώσεις των ευρημάτων της έρευνας που αναδύονται σχετικά με τη διδασκαλία των εννοιών που εξετάζονται, ολοκληρώνουν την παρούσα έρευνα. / In the past few year, in the international and Greek scientific community, is observed an increased interest for how the thought of children approaches the natural world. Thus, the field of research of Natural Sciences is focused in the detection and study of experiential representations of children (Ravanis, 1999). The detection and the recording of these representations are considered important, while are present in the thought of children and constitute obstacles for the comprehension of scientific significances and phenomena (Baster, 1995, Sharp, 1995). This research was carried out, in order to placed a more general reflection, as for the thoughts of children of preschool age, for a geological phenomenon that upsets often the hellenic space, the earthquake. In addition, this research was carried out in order to realize if the children of particular age are sufficiently capable to face this phenomenon as well as its prevention and confrontation. Thus, was attempted the detection of intellectual representations of children of preschool age with regard to geophysical characteristic of ground, in order to it deepens afterwards in the phenomenon of earthquake as well as in the prevention and his confrontation. Initially, it is presented the theoretical frame on which we based to drawn the present research and the conclusions of researches that have been carried out with regard to the subject under review. Then, the report continues with the methodology concept and is presented the results. Finally, the conclusion of this research represents the annotation of results, the conclusions and the discussion as well as the repercussions of discoveries of research that emerge with regard to the teaching of significances that is examined.

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