Seismic Imaging Using Electromagnetic Vibrators - Storm versus Lightning

Seismic imaging using two electromagnetic (EM) vibrators (E-vibes) based on linear synchronous motor principle was evaluated via a seismic survey in central Netherlands. The sources, Storm and Lightning, weigh 1650 kg and 90 kg, respectively. Storm is a vertical-type vibrator with full drive frequency 2-200 Hz and peak force of 7 kN. Depending on the orientation, Lightning can be used either as P- or S-wave vibrator with full drive frequency 8-400 Hz and peak forces of 1.7 kN (S-wave) and 1.2 kN (P-wave). Data were acquired using a 100-unit-long three-component microelectro-mechanical (MEMS-based) seismic landstreamer and 253 wireless seismic nodes. We analyze and compare data recorded using both sources and vertical components of different seismic receivers (MEMS versus geophones), along with different acquisition strategies in terms of signal quality, maximum penetration depth and offsets. Shot gathers and stacked sections indicate great potential of both sources for broadband (2-200 Hz) seismic imaging with excellent quality data from 50 ms to 1.6 s (~2000 m depth) using the Storm and comparable, but of lower quality and resolution, using the Lightning source. Bellow 1.6 s, coherent events are absent on the Lightning data while the Storm shows weaker events down to 2.2 s.