LE-xD/5s: High Performance 0.2 Hz Seismometers

The LE-3D/5s - The LE-1DV/5s Seismometers:

The LE-3D/5s Seismometer

This instrument is the runner-up in terms of popularity, providing flat velocity response down to 5 seconds while still preserving basic fieldworthy qualities such as ruggedness and portability. It quickly gained acceptance among those requiring a little bit of extra low frequency response.

Recently, a single-component vertical version has been requested by GFZ Potsdam to be used in site evaluation studies for the GITEWS Tsunami Early Warning System (scroll down for details on the 1D version).

LE-3D/5s is the sensor of choice for a wide variety of field and observatory tasks – being still portable, it will allow you to go places where a broadband sensor just won’t do the job. If space and weight constraints prevail, LE-3D/5s will help you meet them. It is not only the dimensions and weight of the sensor proper that count – do not forget to take power requirements into account. In this department, the LE-3D/5s leaves broadband seismometers in the dust. At only 100 mW, LE-3D/5s won’t require its own truck battery even for a longterm deployment. As an example, a 20 Ah battery (which is still easily handled) will last up to 100 days

But do not believe that this noteworthy power consciousness will incur a significant performance penalty – the noise level of this sensor (approx. 1 nm/s RMS at 1 Hz) is such that it can be used in most low-noise sites without problems.

The LE-1DV/5s Seismometer

The LE-1DV/5s seismometer comes in a stainless steel housing similar to LE-1DV. Other than the different housing and having just one vertical component, it is for all practical purposes identical to the LE-3D/5s. The inside is pure LE-3D/5s, just without the two horizontal components

Features and Benefits of the LE-xD/5s Seismometer:

• Compact and lightweight, rugged construction

• Sheer simplicity; true plug-and-play operation

• All sensors calibrated to identical output voltages; no need to keep records of which sensor has been connected to which datalogger

• Low noise, low power (typically 3-10 mA per component @ 12 V DC)

• Dynamic range > 120 dB

• Comparatively insensitive to improper levelling; no mass lock, mass center, control box, or other contraption required; can be transported in any orientation

• Proven long-term stability; over twenty years of field experience

• The Lennartz 5sec sensors are the best performing in terms of the frequency range and sensitivity

Technical details for the LE-xD/5s Seismometers