LTME is a high-end capacitive MEMS accelerometer which is specially designed for strong motion class B seismic measurements. Thanks to its extremely low noise, low power and wide frequency response the LTME family guarantees accurate and stable seismic measurements without the need for recalibration or maintenance during the lifecycle of the system.
LTME is available in two dynamic ranges 90dB and 110dB and different full-scale ranges depending on the model (±2g, ±3g, ±5g).
The broadband linear response is from DC to some hundreds of Hz (different for each version).
LTME sensitive elements are mounted orthogonally and housed in hard coating aluminum case IP67; IP68 is available optionally.
The resolution of the entry level model 90dB, meets all the requirements for strong motion event monitoring. Already in presence of light tremors, the data output is completely overlappable with mechanical force balance. The LTME response fades into noise when the ambient noise is low, whereas a true force balance can provide consistent information.
The graph below is a comparison between one of the most popular true force balance mechanical accelerometer for seismology and LTME.
During the test the two accelerometers were installed side by side in a site in the central regions of Italy where there is constant seismic activity. The event in the graph is Magnitude 3.5 while the epicenter was registered at 20Km from the installation. The unequal test provides surprisingly good results for LTME. As you can see the time traces are completely overlapped. A closer look at the spectra reveals that the spectral coherence is close to 1 in the band from 0.3Hz up to 30 Hz. This band is suitable to detect local seismic events. Moreover, the cross correlation between traces has a maximum in 0 (no phase delay). The difference in the histogram clearly shows that LTME 90 resolves vibrations well below 1mg.