The present-day crustal in-situ stress field is of extreme importance for understanding both natural processes (e.g., understanding neotectonics, earthquake, and seismic hazard assessment) and anthropogenic activities (e.g., exploration and production of geothermal energy, groundwater, hydrocarbon, mineral resources, CO2, and hydrogen geo-storage). Analysis of the present-day stresses in numerous basins from across the world reveals that significant and complex variations in the present-day stress orientation are commonly observed at different scales. This lecture aims to investigate the pattern of crustal stress at different spatial scales to better evaluate the causes and consequences of contemporary stress in the earth’s crust.
I will give an overview of the crustal stress analysis at different spatial scales to explain the variability of present-day stress from tectonic plate scale to wellbore scale with examples from more than 25 sedimentary basins from across the world. Also, I will provide an overview of the in-situ stress analysis using borehole data. Then, I will explain the concept of stress mapping, which is a well-established method for investigating the relative contribution of different sources of stresses from plate-scale, generated by plate boundary forces, to small-scale owing to local sources of stresses. Hence, several stress maps from basin to continent-scale are discussed.
Stress patterns in basins can vary from highly uniform to extremely complex depending on the geology and tectonics of the basin. Analysis of in-situ stress data from numerous case examples has revealed that the stress pattern at any given point is the result of superposition and summation of all forces acting at hundreds of kilometers to a couple of meters. With several examples from Australian sedimentary basins, I will show that the in-situ stress orientation is controlled by the relative combination of plate boundary forces, major intra-plate stress sources, basin geometry, mechanical stratigraphy, and geological features. Using these examples, I will discuss the orders of crustal stress sources and explain that the knowledge of geology can be used to understand and predict the likely stress orientation, or degree of complexity, encountered in a basin. Finally, I will discuss the implications of in-situ stress data in a wide range of earth science disciplines, ranging from the tectonic plate-scale to reservoir and wellbore scales in different earth science disciplines.
Dr. Mojtaba Rajabi is an ARC DECRA Fellow at the School of Earth and Environmental Sciences, University of Queensland. He has more than 14 years of extensive experience in crustal stress analysis, geomechanics, and geomechanical-numerical modeling. He graduated with a PhD in Earth Sciences from the University of Adelaide in 2016. Dr. Rajabi has worked on the geomechanical analyses of more than 30 sedimentary basins from across the world including Australia, New Zealand, the Middle East, Mozambique, Iceland, and the Western Mediterranean. Since 2012, Dr. Rajabi has worked on the Australian and World Stress Map projects. He has received over 15 prestigious awards and prizes for his research including the ARC-DECRA Award, the Australian SEG Early Achievement Award, EAGE Louis Cagniard Award, the Royal Society of South Australia's H.G. Andrewartha Medal, and the International Lithosphere Program’s Flinn-Hart Award.
Virtual lecture dates coming soon.