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Here is a listing of PASSCAL News items from the last 6 months. If you want to look up something older, you should check the News Archive.

SmartSolo archives flipped polarity (IGU-16HR 3C 5Hz)

Dear EarthScope Community and PASSCAL PIs:

In September of 2023 we discovered that SmartSolo node (IGU-16HR 3C, 5Hz) data archived from PASSCAL experiments has a non-standard polarity on the Z-channel relative to the down-positive industry geophone convention. Details of this discovery and the steps that will be taken to correct this discrepancy, which will affect the existing and future archives, are outlined below.

Issue

The expected polarity for data archived from PASSCAL experiments are as follow:

Broadband seismometer – Up (Z-dip = -90), North and East motion produce a positive polarity. Geophone – Down (Z-dip = +90), North and East motion produce a positive polarity

Data archived, both PH5 and SEED, prior to October 05, 2023 from PASSCAL experiments using the SmartSolo nodes have the following polarity and metadata mismatch: 

Magnetotelluric Systems at PASSCAL

Magnetotelluric (MT) methods are used to produce conductivity models of the crust and upper mantle through the recording of geoelectric and geomagnetic field variations at the Earth's surface. Depending on the period of the recordings, these methods can provide results from a few hundred meters depth (short period) to 30 km or deeper (long period). Conductivity is a physical property, which is complementary to seismic velocity, and which is very sensitive to the presence of fluids. When seismic and MT data sets are measured together, the additional data can dramatically improve determinations of the structure of the crust and mantle.

 

 

Since 2019, the EPIC (formerly known as PASSCAL) has been developing MT resources to meet PIs needs. We currently have a wide pool of MT equipment including both long-period (LEMI) and wideband (Phoenix) systems.

 

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