Here are some of the articles that have been recently posted to the PASSCAL website:

Installing Broadband Sensors

Introduction:

This manual covers the following tasks related to installing broadband sensors:

Orient sensor Level sensor Connect sensor to DAS (power) Unlock masses (manually or via electronic command, if masses are the type that lock) Center masses (via command) Check waveforms, e.g. stomp test

Note, always handle sensors with care. If you have never worked with sensors or been shown how to install them, you should get help from experienced people, or barring that, carefully read the manufacturer's manual. Never move an unlocked sensor, unless the sensor has no mass locks. Most of the broadband sensors in the EPIC fleet are either Streckeisen STS2's or Guralp 3T's; both models have 3 masses and all 3 need to remain locked during transport.

Station Siting Considerations

April 20th, 2009

These documents address things to consider regarding Station Siting Location/Access, Cultural Noise, and Suggested Materials.

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Seismic Vaults

Introduction:

The construction of the vault for broadband seismometers has a direct impact on the data quality. The principle of broadband sensor vault design is to minimize temperature changes, and to distance the sensor pad from the surficial layer which tilts due to temperature, precipitation, solar insolation, wind, etc.

Nearby sources of ground noise, like footsteps or acoustic noise, are reduced by shallow burial (2-5 ft.) The construction must be adapted to the site and materials available. A decision will have to be made to balance the cost and labor of different vault designs against the length of deployment, resources available, and quality of data expected.

Finding a pre-existing enclosure is a tremendous savings in time and effort. This might include missile silos, power stations, abandoned mines, caves, or root cellars. Consider the details of cables, power, and locating a GPS antenna for timing at these sites.

Guideline Documents

 

May 7, 2009

 

Here are links to documents that will help you to think about seismic station siting considerations and seismic vault construction during planning stages, field reconnaisance, and instrument deployment. Also included here are links to guidelines and procedures for station installation and station servicing.

 

Year Round Equipment for Polar Projects

Here are several documents regarding year round equipment for Polar Projects. Batteries DAS Power Box Sensors Solar Station Enclosure Vaults

Intermediate Sensors

EPIC Intermediate-Period Sensors: Guralp CMG3-ESP Guralp CMG40T Nanometrics Trillium40 Features:

The low-period corner is 30 seconds for the 3 Guralps and is 40 seconds for the Nanometrics sensor. All are 3-component feedback sensors. The CMG40T and Trillium40 masses do not lock. One should still ship and handle them with care so as not to damage them. The CMG3-ESP has masses that require manual locking and unlocking.  For information on the CMG40T with corner-frequencies of 1-sec, click here.

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Station Servicing Common Failures

Murphy was Right!

There is a long litany of things that can go wrong during station servicing, including:

Station Installation Suggested Materials List

Introduction:

One of the worst things that can happen during a deployment, especially a highly remote deployment, is not having the correct tools or supplies.  The following is a minimum suggested list of things to take if you are constructing a station that will house EPIC equipment for more than a few weeks. This list is in addition to the construction materials that will be used to make vaults, enclosures and fences.  Usually this would pertain to passive-source, broadband (or midband) experiments that deploy equipment for 1-2 years and will be visited approximately every three months during that time in order to check the data and the condition of the station.  EPIC will advise if any other specialty tools are required.  Please adjust quantities to provide for all installation teams and number of stations.

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Station Service Procedure

Although EPIC station installations can vary according to the type of equipment being used, servicing is relatively straightforward and similar between station designs and equipment. 

Station servicing has 3 main goals:
• To retrieve waveform data recorded by the station since the previous service;
• To identify and rectify any problems with equipment or damage to the station;
• To refresh consumable items such as compact flash (CF) cards, batteries, etc.

A simple station with easy vehicular access should take around 20 man-minutes to service.

Solar Panels

EPIC has both 30 and 65 Watt solar panels available.

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