Speaker
Description
In the last decades, the impacts of solar activity on grounded infrastructure through the interaction of the Earth’s magnetic field with the solar wind have been classified as a major natural hazard in many mid-high latitude countries. Induced geoelectric currents are well known to affect grounded infrastructure like the high voltage power grid, causing damage to transformers. Less studied impacts include the disturbance of signalling in electrified railways during geomagnetic storms. The observed effects are closely coupled to the local geology due to variations in the electrical conductivity of rocks. The regional conductivity distribution can be estimated from magnetotelluric (MT) measurements, which then enable accurate large-scale modelling of the time-varying ground electric field during magnetic storm times. In the UK, a recent field campaign has added 20 MT sites to an existing data set of 70, improving the spatial coverage and resolution of the geoelectric field model especially in areas of high lateral contrasts in conductivity and the location of some of the major railway lines.
Here we describe the newly collected MT data, the refined geoelectric field model and quantify the impact of improved resolution to the modelled effects on railway signalling during geomagnetic storms in 2024.
