Seminar has been canceled due to current events
Tectonic earthquakes at plate boundaries, intraplate seismicity, as well as induced and triggered events indicate that the Earth’s crust seems to be critically stressed. At plate boundaries the recurrence time of earthquakes is tens to hundreds of years whereas for intraplate seismicity in low-strain areas it has recently been speculated that it is not a stationary process at all. To assess the criticality we need to quantify the contemporary 3D absolute stress state and its temporal changes due to a wide range of natural and anthropogenic processes as well as the failure criterion and its spatio-termporal variability. These ingredients are essential for our understanding of geodynamic processes such as global plate tectonics and earthquakes as well as for the exploration and management of e.g. geothermal reservoirs or storage of energy and waste in the underground. I will present our current knowledge of the present-day crustal stress field and give a brief tour through the history of the World Stress Map (WSM) project and its future developments. The latest WSM database release 2016 with a significant higher data density in some areas revealed a number of unexpected horizontal stress tensor rotations in intraplate regions of 40°-60° within less than 100 km. These rotations can be used to better understand the relative importance of plate boundary forces that control the long wave-length pattern in comparison to regional and local controls of the crustal stress state. I will also show results of a 3D forward model that we use to predict the spatio-temporal evolution of the stress field in Marmara Sea and to generate earthquake scenarios. In another approach stress data are used in an energy-conserving seismicity model for Southern California which allows us to speculate on the strength of the San Andreas Fault and the seismic efficiency. The final example will be a 3D geomechanical-numerical model of the greater area of Munich that shows how much stress is beneath the lecture room and if the stress state critical or not. Is the Earth’s crust critically stressed?
https://www.munich-geocenter.org/events/seminars/frontiers-in-earth-sciences-24/frontiers-in-earth-sciences-2020-06-05
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Seminar has been canceled due to current events
Abstract
Tectonic earthquakes at plate boundaries, intraplate seismicity, as well as induced and triggered events indicate that the Earth’s crust seems to be critically stressed. At plate boundaries the recurrence time of earthquakes is tens to hundreds of years whereas for intraplate seismicity in low-strain areas it has recently been speculated that it is not a stationary process at all. To assess the criticality we need to quantify the contemporary 3D absolute stress state and its temporal changes due to a wide range of natural and anthropogenic processes as well as the failure criterion and its spatio-termporal variability. These ingredients are essential for our understanding of geodynamic processes such as global plate tectonics and earthquakes as well as for the exploration and management of e.g. geothermal reservoirs or storage of energy and waste in the underground.
I will present our current knowledge of the present-day crustal stress field and give a brief tour through the history of the World Stress Map (WSM) project and its future developments. The latest WSM database release 2016 with a significant higher data density in some areas revealed a number of unexpected horizontal stress tensor rotations in intraplate regions of 40°-60° within less than 100 km. These rotations can be used to better understand the relative importance of plate boundary forces that control the long wave-length pattern in comparison to regional and local controls of the crustal stress state. I will also show results of a 3D forward model that we use to predict the spatio-temporal evolution of the stress field in Marmara Sea and to generate earthquake scenarios. In another approach stress data are used in an energy-conserving seismicity model for Southern California which allows us to speculate on the strength of the San Andreas Fault and the seismic efficiency. The final example will be a 3D geomechanical-numerical model of the greater area of Munich that shows how much stress is beneath the lecture room and if the stress state critical or not.
Is the Earth’s crust critically stressed?
