By adapting and calibrating Bakun and Wentworth's (1997) solution strategy for seismic intensity observations for the Northern and Middle Rhine Area (NRA), Central Europe, local magnitudes with objective confidence-level uncertainties are estimated for 23 test-set earthquakes that occurred between 1692 and 1963. Analysis of 4375 Medvedev Sponheuer Karnik intensity (MSKI) observations for 14 instrumentally recorded and located training-set events suggests that an intensity magnitude, MLI, corresponding to local magnitude, ML, can be determined from the mean of MLIi = (MSKIi + 0.7374 + 0.0184 * Δi)/1.2673. Δi is the distance in km of observation MSKIi. In a grid of 81 × 51 trial epicenters, 5-km grid-point distance, contours of rms [MLI], where rms is the root mean square, bound the epicentral region. A total of 3628 intensity observations was used for the test-set earthquakes, seven of which showed MLI ≥ 5.5. The strongest historical events are the Verviers 1692 and the Düren 1756 events with MLI values of 6.8 and 6.4, respectively.

You do not have access to this content, please speak to your institutional administrator if you feel you should have access.