Tarje Nissen-Meyer
Lecturer in Geophysics, University of Oxford
Over tens of millions of years of evolution, animals have developed an impressively diverse range of methods for distributing and gathering information between species and within their natural environment. Amongst these, mechanical vibrations such as seismic waves are perhaps the least understood means of exchanging information. Yet, they offer numerous potential biological uses of communication for a diverse range of animals such as spiders, moles, worms and elephants, complementing air-borne sound, visual or scent-based information exchange and sensing. This stems from the physical nature of multiscale, information-rich, and long-range ground-borne waves, which are independent of disturbances such as weather conditions, airborne noise, or surface obstacles such as topography or vegetation. We have recorded seismic, acoustic and visual data in the Kenyan savanna to monitor the vibroscape of elephants and other large mammals. We developed machine-learning techniques to detect, localise and discriminate species. We classify their behavior based on seismic waveforms alone, suggesting we can use seismic vibrations to remotely monitor behaviours - either for conservation and/or research into elephant communication/sociality. Our results indicate that elephants seek to actively produce, record and act upon seismic rumbles over significant distances.
Spanning seismology, zoology, machine learning, geology, engineering, and conservation, our multidisciplinary project is ongoing with future field work planned using large, dense seismic arrays. Ultimately, we seek to decipher this enigmatic mode of communication by determining the influence of terrain and environmental factors, inter-species communication, and collective animal behavior. We will utilise this insight to assess anthropogenic influences on wildlife behavior such as human-wildlife conflict, impact of droughts and climate change, offering a viable alternative for wildlife monitoring in the face of the ongoing biodiversity crisis.
A geophysicist at the Department of Earth Sciences, and a Fellow of Wolfson College, University of Oxford. Nissen-Meyer is primarily interested in wave phenomena, as related to earthquakes and other sources, planetary interiors, numerical methods and machine learning. As a global geophysicist and human being, Nissen-Meyer collaborates beyond any geographical, cultural, political borders and warmly welcome interest from any background and place on this pristine planet that we strive to understand and protect. His research is concerned with understanding, modeling, deciphering and infering from waves. Modeling realistic wave propagation to address fundamental questions on Earth’s interior between sedimentary basins and the core, from Mars to icy worlds, from earthquakes to elephants, nuclear monitoring to earthquake hazard and ocean storms. developed the axisymmetric spectral-element method AxiSEM, as well as AxiSEM-based database methods instaseis and syngine, and the link to seismic tomography via MCKernel. These methods are used in research and teaching around the world. More recently, introduceding AxiSEM3D, a comprehensive, modern method to solve wave propagation very efficiently by exploiting wavefield smoothness, which can be applied to a range of complexities (asteroids, Mars, bathymetric oceans, deep mantle, tomography, exploration geophysics). Embarking on physics-informed deep learning for wave propagation and inversion, and on hybrid modeling as well as first-order scattering methods. Each method has a realm and limit of validity, and is thus tailored for specific applications. Altogether, our methodological portfolio can address many applications in seismology and related disciplines.
