Previous studies have documented a systematic discrepancy between probabilistic seismic hazard maps and historical records of shaking (Stein et al., 2015; Brooks et al., 2016, 2017, 2018, 2019; Salditch et al., 2020; Salditch, 2021). In almost every case, shaking predicted by the hazard map is higher than that historically observed....
To better prepare for earthquakes, we need to know how large they will be, how strong the shaking will be, and how often they will occur. To answer these questions, seismologists look to past earthquakes to better understand future hazards. Earthquakes, however, are complex physical phenomena that occur on timescales...
The excitation of seismic waves depends on the geologic processes of an earthquake. The waveforms at seismic stations can be modeled as linear combinations of derivatives of Green's functions, which describe the response at the receiver location due to excitation at the seismic source location considering wave propagation effects given...
Failed continental rifts provide unique opportunities to study aspects of plate tectonic evolution frozen in time. North America contains three major failed rifts: The Midcontinent Rift (MCR), Southern Oklahoma Aulacogen (SOA), and the Reelfoot Rift (RR). To understand why some rifts fail and why others might succeed to seafloor spreading,...
How well do Probabilistic Seismic Hazard Analysis (PSHA) maps forecast ground shaking due to earthquakes? This question is central to ensuring the safety, security, and economic well-being of citizens. PSHA maps are an important product for users including seismologists, engineers, insurers, and policymakers. PSHA, which has been used worldwide for...
Earth’s mantle has a two-layer structure comprising an upper and a lower mantle, separated by a global seismic discontinuity at 660 km depth. The mantle transition zone (MTZ), which extends from the seismic discontinuity at 410 km depth to the base of the upper mantle plays a crucial role in...
This dissertation addresses problems in the source properties of major earthquakes. It is composed of four largely independent studies. In chapter 2, we explore the possible theoretical origin of the distance-depth correction q(, h) introduced 75 years ago by B. Gutenberg for the computation of the body wave magnitude mb,...
This thesis focuses on two research topics: investigating dynamically generated seismic structures at the topmost outer core and studying dynamically triggered seismic events in the Earth’s crust. Earth’s liquid-iron outer core convects vigorously and contains buoyant light elements that accumulate at the top of the outer core. Modeling of seismic...
The term compaction band identifies a rich variety of structural features of the Earth's crust that affect formations of sedimentary rocks. The most common definition for compaction band often found in the literature describes them as narrow planar zones of concentrated porosity reduction, which may involve limited to none shear...
This thesis deals with modeling long-term deformation and failure of concrete and shale structures. First concrete structures are studied. For concrete structures, design lifetime of over a hundred years is required. Shrinkage, swelling, creep and Alkali-silica reaction are significant parts of the long-term deformation of concrete and are studied here....
