# Satellite Measured Ionospheric Magnetic Field Variations over Natural Hazards Sites
## 8 Conclusions  
In most of the presented cases and events the statistical results from the wavelet analysis show a change in the pattern between pre- and post-event periods. Wavelike features are found for the China Seismo-Electromagnetic Satellite (CSES) Coupled Dark State Magnetometer (CDSM) scalar measurements. The analysis of the components from the vector field instruments, i.e., CSES fluxgate magnetometer (FGM1) and _Swarm_ A/B/C Vector Field Magnetometer (VFM), show enhancements and attenuations along specific frequency bands. The spatio-temporal confinement to a few degrees in lat/long directs the focus to a limited area, which could be a part (diameter) of a complex atmospheric wave propagation channel from bottom to top, in a certain sense a cross section from a transmission tube which is traversed by satellites at Low Earth Orbit (LEO) altitudes. The synchronous behaviour of the _Swarm_ A/C VFM components for the Baroarbunga (Iceland) volcano sequence suggests a transit through the same structure, observational biases in causing this trend are unlikely. Enhancements, mainly for the earthquake events, see Figure 11 for CSES FGM1 case studies, indicate energy transfer to the plasma, the wave-like feature a redistribution between different scales and later on dissipation occurs to background levels. The small enhancements from the explosion events could be related to compressional signatures from acoustic waves, but overall the pattern are weak. For the rocket launches at least one component shows alterations, energy transfer into the plasma at LEO altitudes related to acoustic waves is a reasonable explanation. **Author Contributions:** The authors contributed in the following way: conceptualisation and software, C.S., H.U.E., M.Y.B., and K.S. ; methodology, C.S., H.U.E., and M.Y.B. ; validation (in terms of project specific scientific goals), W.M. ; formal analysis, B.P.B., M.D., and M.Y.B. ; investigation (expertise about ground based natural hazards issues), P.F.B. and M.S. ; resources (in particular in the frame of CSES HPM), A.P. ; data curation, X.S., J.W., B.C., B.Z., and A.P. ; writing-original draft preparation, C.S. and H.U.E. ; writing-review and editing, B.P.B. ; visualisation, C.S. and H.U.E. ; supervision, project administration, and funding acquisition, W.M. and R.L. All authors have read and agreed to the published version of the manuscript. **Funding:** This research contract from C.S. was funded by Austrian Research Promotion Agency (FFG) in the frame of FFG project number 873688 (ASAP 15, Oriented Basic Research), short title \"CDSM for CSES 2\", under the two project leading participants (i) Space Research Institute (IWF), Austrian Academy of Sciences (OeAW), and (ii) Institute of Experimental Physics (IEP), Graz University of Technology (TUG). The Article Processing Costs (APC) were co-funded by Open Access (OA) Fonds, Austrian Academy of Sciences (OeAW). **Data Availability Statement:** Publicly available datasets were analyzed in this study. This data can be found and accessed as stated in the section \"Materials\". **Acknowledgments:** We kindly acknowledge the long-term administrative support from [PERSON], [PERSON], [PERSON], [PERSON], [PERSON], and [PERSON] in legal advice and business affairs. Support in computational issues and network services were mastered by [PERSON], [PERSON], [PERSON], [PERSON], and [PERSON], we highly appreciate their expertise and active assistance. [PERSON] from the space plasma physics group and [PERSON] from the general management contributed with expert knowledge. We thank the ISGI involved national institutes and the INTERMAGNET network. We appreciate the excellent work of the _Swarm_ and CSES teams who made these missions and instruments a success. Sincere thanks are given to them all! Figure 11: Relative changes based on median values of pre- and post-variations for the earthquakes M6.5 Severo-Kurilsk, M7.3 Rio Caribe, M8.2 Ndoi Island, and M7.1 Ridgecrest from CSES FGM1 magnetic field measurements.