Climate and Georisks
Climate and geo-risks include natural hazards like earthquakes, storms, flooding, heat waves, cold snaps and volcanic eruptions – but also man-made risks, such as collapsing hillsides due to erosion or water seepage, or micro-quakes caused by underground CO2 sequestration. To effectively minimize these risks, integrated research efforts are called for. In this regard, the CEN draws on its varied expertise: numerical models, observations, mathematical theories and a sound understanding of geophysical mechanisms are essential to predicting extreme events. The results of these efforts are fed into economic and geographic model studies exploring e.g. scenarios for using financial incentives to reduce the emission of climate-relevant pollutants; the outcomes are reflected in the resultant models, which are used to test their efficacy.
SIMULTAN: Subrosion and instability of sinkholes . Integrated MULTi-scale monitoring and Analysis
Due to the widespread occurrence of water-soluble rocks in the shallow subsurface in Germany, sinkholes represent a significant natural hazard – also in urban areas. The project SIMULTAN aims to develop and apply an early recognition system of sinkhole instability, unrest and collapse in Germany. The project seeks to improve the physical understanding of subrosion- and sinkhole-processes on different space and time scales using multidisciplinary research methods. The aim of the project is to improve the early recognition of instability, restlessness and collapse of sinkholes by using geophysical methods. The seismic monitoring methods for urban seismic events developed in the subproject may also be useful for finding weak seismic events in other (including future) data sets with strong interfering and noisy signals (like urban geothermal projects, seismicity characterization of recent near surface tectonics or carbon capture and storage)
Project Lead (Subproject 2: Seismic monitoring and characterization of sinkhole areas): Dr. Dirk Becker
Sponsor: Bundesministerium für Bildung und Forschung (BMBF)
WIT: Wave Inversion Technology
In order to arrive at the most accurate picture possible of the Earth’s interior and the related physical properties and processes, more precise methods for the evaluation of seismic reflection data are called for. The Wave Inversion Technology (WIT) consortium is working to develop techniques for the optimal imaging of underground structures and properties using waves created under controlled conditions.
Within the context of these developments, one of the consortium’s aims is to train future generations of experts in the field of geophysics research. Founded in 1996, the WIT is an international project bringing together scientists from Hamburg, Karlsruhe and Campinas, Brazil and funded by companies from the energy industry.
Project leader: Prof. Dr. Dirk Gajewski
Third party funders: various companies from the energy sector
StrucFlow: Neotectonic and fluid dynamics in the marine sector of the North German Basin
On the basis of high-resolution reflection seismic data and in cooperation with German, Swedish and Polish partner institutes the project aims to 1.) delineate the continuation of faults from bedrock to seafloor 2.) to quantify the deformation history of the Rotliegende 3.) understand the salt tectonics of the Northern German Basin; 4.) explore ice-load-induced tectonics; and 5.) investigate fluid migration from meso- to paleozoic reservoir and bedrocks to the seafloor. Hypotheses are: a) that the regional stress field and differential ice load reactivated old fault systems or gave rise to new faults in the shallow surface up to Earth surface, that b) the salt tectonic in the peripheral area of the Northern German Basin can be explained by gravitational collapse and that c) the hydrocarbon system in the study area is permeable. For public service relevant findings in the topic area of CO2-sequestration, geo-Engineering and permanent disposal are expected.
BMBF Joint Project – Detecting Gravitational Waves
Astrophysical events like the merging of two black holes produce vibrations in spacetime, referred to as gravitational waves. These phenomena can be detected using special-purpose facilities: gravitational wave observatories. Though Albert Einstein postulated the existence of gravitational waves roughly a century ago, the first experimental proof wasn’t delivered until 2015. Today, researchers are already working on the third generation of observatories. That generation includes the planned Einstein Telescope, which is intended to more precisely measure the reverberations of the Big Bang and provide detailed insights into merging processes in space. To do so, the telescope will cover a frequency range from less than ten hertz to over 500 hertz, a point at which today’s gravitational wave observatories reach their limits.
In this regard, Universität Hamburg’s Institute of Geophysics is working to improve the telescope’s sensitivity in the low-frequency range. To do so, a method is being developed to predict the gravitational coupling of seismic waves at the position of the mirror, so that this effect can be retroactively compensated for. An effect known as gravitational gradient or Newtonian noise, in which the attracting forces affecting the pendulum are influenced by movements in the surrounding area, can be predicted using a network of seismometers. The challenge lies in filtering the countless signals to find the actual source of noise. To help researchers accomplish this task, new machine learning methods are being developed and applied.
Germany’s Federal Ministry of Education and Research (BMBF) is supporting the joint project, led by the RWTH Aachen, with ca. three million euros of funding, spread over three years. More than half a million euros will go to three subprojects at Universität Hamburg, including one at the Institute of Geophysics.
SUBMON: Registration and Characterization of acoustic emissions
The project SUBMON is a subproject of the project “Tomography of diffracted wave fields”. Acoustic emissions of different strengths are constantly generated in the earth’s subsurface. They can have tectonic causes leading to earthquakes. However, anthropogenic causes like, e.g., the injection of CO2 in storage sites, the extraction of hydrocarbons or mining and excavation can lead to such events as well. The kinematic properties of these seismic events follow the general principles of diffracted waves, which can be observed in reflection seismics. The localization of acoustic emissions in space is a crucial part of monitoring the subsurface, as geo risks and hazard potentials can be assessed. The knowledge of wave velocities in the subsurface – measured with tomographic methods – is required, to exactly localize the events.
MEDSALT COST Action CA15103 : Uncovering the Mediterranean salt giant
MEDSALT aims to create a new flexible scientific network that will address the causes, timing, emplacement mechanisms, and consequences at local and global scales of the largest and most recent 'salt giant' on Earth: The late Miocene (Messinian) salt layer in the Mediterranean basin. It is a 1.5 km-thick salt layer that covered the bottom of the deep Mediterranean basins about 5.5 million years ago and is preserved beneath the deep ocean floor today. The origin of the Mediterranean salt giant is linked to an extraordinary event in the geological history of the Mediterranean region, commonly referred to as the Messinian Salinity Crisis. This inter-sectorial and multinational cooperation network will comprise a critical mass of both experienced and early-career researchers from Europe and beyond. The goal will be achieved through capacity building, researchers’ mobility, skills development, knowledge exchange and scientific networking.
VolcHaz: Volcanic Threads
On the one hand, volcanoes are a fascinating natural spectacle, on the other hand they shelter dangers with local, regional but also global effects. Local dangers include so-called pyroclastic flows and the case of large quantities of ash, which may also demand human lives and destroy or seriously affect the infrastructure. Regional hazards also include ashes, which can lead to respiratory diseases and also affect the infrastructure and possibly the air traffic. At global level, climatic effects play a role, e.g. when volcanic activity causes large quantities of aerosols to reach the stratosphere. However, the loss of key industries due to a volcanic eruption (for example, Mt. Rainer near Seattle, USA) may also disrupt the global economy.
In order to better protect both human lives and infrastructure from the effects of volcanic eruptions, there is a great need for research in understanding physical processes before and during volcanic eruptions. The focus is on transport processes along the last kilometer before the outbreak. Both numerical models and observations on volcanoes are used here. To capture the local and regional effects of volcanic eruptions, algorithms are being developed to better predict the transport of volcanic ash.
CO2RES: Characterization of CO2 deposits using seismic methods
Germany (and other countriesfail to reach the goals defined in climate conferences to reduce CO2 emissions. Therefore, for the time being, bridging technologies must be used in order to achieve the climate goals. The sequestration of CO2 into the ground is a suitable instrument. Potential CO2 deposits must be found, probed for their reservoir properties, and evaluated for potential geo-risks. These tasks can be considered using seismic methods. For imaging of the subsurface, procedures are necessary, which display details in the subsurface with high accuracy and resolution. Such techniques are also used and developed for the exploration of raw materials. CO2RES is a subproject in the “Wave Inversion Technology Consortium”.