GSR-12 / 16 / 18 AS-12 / 16 GCR-12 / 16

GSR-12 / 16 / 18 AS-12 / 16 GCR-12 / 16 User Mnul GeoSIG Ltd, Ahornweg 5, 5504 Othmrsingen, Switzerlnd Phone: + 41 44 810 2150, Fx: + 41 44 810 2350 info@geosig.com, www.geosig.com

GeoSIG Ltd. GS_GSR_GCR_UserMnul_V21.doc / 18.09.2009 Pge ii GSR / GCR / AS User Mnul Document Revision Author Checked Approved Dr. Tlhn Biro Johnnes Grob Christoph Kuendig Version Action 17.12.97 Formt revision 13.09.99 Formt revision 18.07.2000 Chnges of nme 23.08.2000 Added Intensity Scle (LG) 16.02.2001 Added seril dt out for GSR-18, V 02.02.xx 16.07.2001 Chnge of new softwre title 15.10.2001 Chnges for UL pprovl (LG): Added remrk AC powered GSR only in sections contining fuse instructions Chnged bttery type of min bttery from 6.5 Ah to 7.2 Ah in section 2.1.5 Added section 2.1.7 bout externl DC power supply Chnged pinout in ppendix B for 15 VDC input (section 9) Added section 4.2.2 bout Connection of externl DC power supply Added section 4.2.5 bout Interconnection instlltion 12.07.2002 Chnges mde to AS-12/16 (JG) 18.03.2003 Chnges mde to chpter 4.2.1 (LG) 16.04.2003 4.2.3 Requirements for the GSR foundtion dded (TB) 18.06.2003 Chnges mde to integrte GCR into GSR mnul 15.01.2004 Intensity scle for GSR-18 08.04.2004 Adjustments concerning the new communiction progrms (PC) 12.05.2004 Formul formt of Signl Conditioning nd Triggering corrected (TB) 10.06.2004 Preliminry formtting nd templte chnge for updte (TB) GSR-18 trigger filters described (TB) 25.01.2005 Revision of Active Chrge LED (TB) 16.03.2005 Chnges concerning the new GSR-12 / 16 using GS_DBMN (PC) 24.05.2005 Revision of templte nd text flow (TB) 02.08.2005 Additionl explntion for Alrm Output (PC) 07.11.2006 Updte of Interconnection referring to Appendix G (TB) 11.03.2009 Chnge of Address [STT] Disclimer GeoSIG Ltd reserves the right to chnge the informtion contined in this document without notice. While the informtion contined herein is ssumed to be ccurte, GeoSIG Ltd ssumes no responsibility for ny errors or omissions. Copyright Notice No prt of this document my be reproduced without the prior written consent of GeoSIG Ltd. The softwre described in this document is furnished under license nd my only be used or copied in ccordnce with the terms of such license. Trdemrk All brnd nd product nmes mentioned re trdemrks or registered trdemrks of their respective holders. All rights reserved. GeoSIG Ltd Switzerlnd

GS_GSR_GCR_UserMnul_V21.doc / 18.09.2009 GSR / GCR / AS User Mnul GeoSIG Ltd. Pge iii Tble of Contents Applicbility of This Mnul... v Wrnings nd Sfety... v Symbols nd Abbrevitions... vi 1. Introduction... 1 2. Incoming Inspection... 1 2.1. Dmge During Shipment...2 2.2. Wrrnty...2 3. Description... 2 3.1. Housing...2 3.2. LCD...2 3.3. LED's...2 3.4. Connectors...3 3.5. Opening the Housing...5 3.6. Printed Circuit Bords...5 3.7. Internl Bttery...5 3.8. Internl Bttery Chrger...5 3.9. Externl DC Power Supply...6 3.10. Test Dt Sheet...7 3.11. Options nd Accessories...7 3.12. Storge...7 4. Instlltion, Configurtion nd Opertion... 8 4.1. Site Selection...8 4.1.1. Environmentl Considertions...8 4.1.2. Power Supply Considertions...8 4.2. Instlltion...9 4.2.1. Supply Voltge Selection...9 4.2.2. Connection of Externl DC Power Supply...9 4.2.3. Requirements for the Instrument Foundtion...9 4.2.4. Mounting the Instrument...9 4.2.5. Optionl Interconnection...10 4.2.6. Terminting the Instlltion...10 4.3. First Strt...11 4.4. Configuring Prmeters nd Putting in Opertion...11 4.4.1. Seril Dt Output...11 4.4.1.1. Smple Oriented Mode (SOM)...12 4.4.1.2. Pcket Oriented Mode (POM)...13 5. Functionl Description... 13 5.1. Signl Conditioning...13 5.1.1. Digitl Signl Filtering...14

GeoSIG Ltd. GS_GSR_GCR_UserMnul_V21.doc / 18.09.2009 Pge iv GSR / GCR / AS User Mnul 5.1.1.1. GSR / AS Instruments... 14 5.1.1.2. GCR Instruments... 15 5.2. Triggering... 15 5.2.1. Internl Triggering... 16 5.2.1.1. Threshold Trigger... 16 5.2.1.2. STA/LTA Rtio Trigger... 16 5.2.2. Time Triggering... 17 5.2.3. Softwre Triggering... 17 5.2.4. Externl Triggering (option)... 17 5.3. Triggering Guidelines... 17 5.3.1. Threshold Trigger... 17 5.3.2. STA/LTA Rtio Trigger... 17 5.3.2.1. Micro Event Detection... 19 5.3.2.2. Locl Erthquke Detection... 19 5.3.2.3. Strong Motion Detection... 19 5.4. Dt Recording... 19 5.4.1. Event Directory... 19 5.4.2. Recording Cpcity... 20 5.4.3. Intensity Scle... 20 5.5. Clock... 20 5.5.1. GPS Option... 21 6. Troubleshooting nd Mintennce...21 6.1. Self Test... 21 6.1.1. Anlog... 21 6.1.2. Hrdwre... 22 6.1.3. Rel Time Clock RTC... 23 6.1.4. Bttery... 24 6.1.5. Memory... 24 6.2. Mintennce... 25 Index...27 Appendices: Appendix B. GSR / GCR / AS Connectors

GS_GSR_GCR_UserMnul_V21.doc / 18.09.2009 GSR / GCR / AS User Mnul GeoSIG Ltd. Pge v Applicbility of This Mnul This mnul is pplicble to the Firmwre versions listed below: Firmwre Version V02.02.26 nd up V02.02.17 nd up V02.03.05 V02.04.09 V08.00.02 V08.01.02 V08.02.02 V08.03.02 Remrk Only GSM support Only GSM support Only GSM support Wrnings nd Sfety STATIC ELECTRICITY The Instrument nd if vilble, its sensor unit contin CMOS devices nd when serviced, cre must be tken to prevent dmge due to sttic electricity. This is very importnt to ensure long term relibility of the unit. INSIDE THE INSTRUMENT (MAINTENANCE) Under norml circumstnces, there is no need to remove ny of the printed circuit bord covers inside the Instrument, except for bttery mintennce/replcement. In ny cse, only trined personnel should remove these covers since power enters directly into the Instrument nd cn be dngerous. Moreover untrined ccess my led to serious dmge to the Instrument, s well s my void the wrrnty. Especilly the Lid cover should never be removed without first contcting to GeoSIG or your locl representtive. Before removing ny of the covers, lwys: 1. Flip the min switch to "OFF" 2. Disconnect power supply from the POWER connector 3. Disconnect the min bttery 4. Mke sure tht the green Active Chrge AC LED indictor is OFF BATTERY LIFE The Instrument is shipped with the btteries instlled nd connected, redy for use. If you do not instll it immeditely, you should disconnect the min bttery. Do not forget to reconnect the bttery when you instll the Instrument; the red cble on "+", the blck cble on poles of the bttery. In order to prevent dt loss, you should be wre of tht when memory crd, memory module, bck-up bttery or min bttery re in use, the btteries should be replced before their expected life time expires. Bttery minimum life times under norml conditions re: Min bttery Fimm-GS FG20721 or FG20651 3 yers Pnsonic LCR-12V6,5P 3 yers Yus NP 6-12 or NP 7-12 3 yers Bck-up bttery Vrt CR 1/2 AA SLF 5 yers The lifetime of the min bttery nd bck-up bttery life cn drsticlly chnge depending on operting conditions. Strong dischrge of the min bttery must be voided. When the Instrument is not powered up, the bck-up bttery cn provide power

GeoSIG Ltd. GS_GSR_GCR_UserMnul_V21.doc / 18.09.2009 Pge vi GSR / GCR / AS User Mnul to the internl clock nd to the memory module for totl durtion of one yer. During norml opertion, power comes from the min bttery nd the bck-up bttery life is t lest 5 yers. In cse of using removble memory crds, in order to prevent dt loss: - Never remove the memory crd during opertion - Do not expose the memory crd to high tempertures - Do not expose the memory crd to mgnetic fields or potentil sttic electricity dischrges Symbols nd Abbrevitions Instrument GSR GCR AS CMOS SRAM EEPROM PC Crd CF Memory Crd VDC VAC STA LTA PC SPS AC SOM POM SEISLOG SEISAN FS DV AIV Vpp db RMS GSR-12/16/18 or GCR-12/16 or AS-12/16 GSR-12/16/18 GCR-12/16 AS-12/16 Complementry Metl Oxide Semiconductor Sttic Rndom Access Memory Electriclly Ersble Progrmmble Red-Only Memory Personl Computer Memory Crd Interntionl Assocition (PCMCIA) CompctFlsh Memory Crd DC Voltge AC Voltge Short Term Averge Long Term Averge IBM comptible Personl Computer Smples Per Second Active Chrge Smple Oriented Seril Output Dt Mode Pcket Oriented Seril Output Dt Mode Plese see http://www.geo.uib.no/seismologi/softwre/softwre.html Plese see http://www.geo.uib.no/seismologi/softwre/softwre.html The full-scle input rnge of the instrument Digitl Vlues Anlog Input Voltges Volts pek to pek Root Men Squre Decibels

GS_GSR_GCR_UserMnul_V21.doc / 18.09.2009 GeoSIG Ltd. GSR / GCR / AS User Mnul Pge 1 1. Introduction Der Vlued GeoSIG Customer, thnk you for purchsing this product. These Instruments hve been optimised to meet the requirements of the mjority of customers out of the box nd my hve even be delivered tilored to your needs. In ny cse, to be ble to get the most out of our product, plese crefully study this mnul, its ppendices nd referenced mnuls, s well s ny other documents delivered with it. This is relible nd esy to use device, nd t the sme time sophisticted product, which requires cre, ttention nd know-how in configuring, instlling, operting nd mintennce. The GCR-12/16 nd GSR-12/16/18 re 12, 16 or 18 Bit seismic dt cquisition systems. The AS- 12/16 is 12 or 16 Bit seismic switch with the sme specifictions s the GSR or GCR instruments with lrm trigger output but without recording fcility. All these devices will be referred to s Instrument in this opertion mnul unless needed to be specific. Severl types of internlly or externlly mounted sensors cn be used with the Instrument, like seismometers, geophones, ccelerometers or other sensors with single-ended or differentil outputs. The GSR nd GCR store the event dt in CMOS SRAM, which is power mintined by internl nd/or externl btteries or in removble Memory Crds (Flsh EEPROM/SRAM, CF Memory Crd / PC Crd). Recorded dt include the sensor dt, clock/timing informtion nd instrument configurtion informtion. Frequency response depends on the low-pss filter chosen. For ll except GCR the frequency response is 40% of the smple rte, wheres the smple rtes re 100, 200, nd 250 SPS. During norml opertion the Instrument continuously mplifies, filters nd converts sensor inputs to 12, 16 or 18 Bit digitl form nd psses these to pre-event memory. GCR hs permnent (continuous) recording fcility, wheres in GSR nd AS, when the specified triggering criteri hve been met, the Instrument either begins recording the dt from the pre-event memory nd/or issues n lrm / lrm trigger. In cse of recording, by selecting n pproprite length of the pre-event memory, you cn ensure tht the entire event, including the first rrivl, will be recorded. Trigger lgorithms include STA/LTA rtio triggering nd level triggering. The STA/LTA rtio trigger computes the short term nd long term signl verges fifty times per second (every 0.02 seconds). When the STA exceeds pre-selected multiple of the LTA, the Instrument begins recording dt. The level trigger continuously compres the incoming signl to selected threshold nd triggers when its vlue exceeds the threshold. The Instrument is typiclly configured by connecting to PC (both desktop nd lptop models) with n RS-232 communictions port. Besides configurtion, this connection fcilittes dt cquisition nd performing complete system test from the sensor to the dt storge memory, vi the menu driven softwre GeoDAS. Configurtion, dt cquisition or system tests of n Instrument t remote site my lso be ccomplished through the use of modems or other telecommuniction methods. Utilistion of lptop PC further yields the cpbility to perform these tsks t the site. GeoSIG continuously improves nd enhnces cpbilities of ll products. There my be severl other connectivity, hrdwre or softwre options for the Instrument, which re not covered in this mnul. Refer to seprte documenttion from GeoSIG bout vilble options. 2. Incoming Inspection All Instruments re crefully inspected both electriclly nd mechniclly before they leve the fctory. Plese check if ll received items correspond with the pcking list nd your order confirmtion. In cse of discrepncy plese contct GeoSIG or your locl representtive immeditely.

GeoSIG Ltd. GS_GSR_GCR_UserMnul_V21.doc / 18.09.2009 Pge 2 GSR / GCR / AS User Mnul 2.1. Dmge During Shipment If requested t the time of order, ll instruments cn be insured prior to shipment. If you receive dmged shipment nd shipping insurnce ws previously rrnged you should: Report the dmge to your shipper immeditely Inform GeoSIG or your locl representtive immeditely Keep ll pckging nd shipping documents Insurnce clims my be void if the bove procedure is not followed. 2.2. Wrrnty GeoSIG Ltd. (herefter GeoSIG) wrrnts hrdwre nd softwre products ginst defects in mterils, workmnship nd design for the defined period in the relevnt contrct or offer, strting from dte of shipment nd 5 yers prts nd mintennce support commitment. If GeoSIG receives notice of such defects during the wrrnty period, GeoSIG shll t its option either repir (t fctory) or replce free of chrge hrdwre nd softwre products tht prove to be defective. If GeoSIG is unble, within resonble time to repir or replce ny instrument to condition s wrrnted, buyer shll be entitled to refund of the purchse price upon return of the instrument to GeoSIG. 50 % of freight chrges on shipments of wrrnty repirs or replcements will be borne by GeoSIG (normlly one wy freight). Limittion of Wrrnty: The foregoing gurntee shll not pply to defects resulting from: Improper or indequte mintennce by buyer Buyer supplied softwre or interfcing Unuthorised modifiction or misuse Opertion nd storge outside of the environmentl specifictions of the instrument or Improper preprtion nd mintennce of site. 3. Description 3.1. Housing The Instrument is housed in wether-resistnt, IP 65, cst luminium housing with hinged lid. Informtion regrding the Instrument's dte of mnufcture, seril number, etc. is contined on the ID lbel on the outside of the housing. 3.2. LCD The lphnumeric disply provides detiled informtion bout the Instrument sttus, incoming signl, dte nd time nd wrning/error messges. The informtion to be displyed is user progrmmble nd cn be set vi GeoDAS (see the GeoDAS mnul). 3.3. LED's AC (Active Chrge) This green LED indictes tht the recorder is in stte of Active Chrge to chrge the bttery. The following 3 LED s flsh fter switching on the Instrument.

GS_GSR_GCR_UserMnul_V21.doc / 18.09.2009 GeoSIG Ltd. GSR / GCR / AS User Mnul Pge 3 280mm AC RUN EVENT ERROR 17 180mm SENSOR RS-232 INTERCON OPTION POWER Figure 1. Stndrd Instrument, top view Run This green LED flshes to indicte tht the instrument is running. Event This yellow LED is illuminted during recording n event. After recording, the LED indictes the presence of one or more recorded events by flshing. Error The red LED flshes if n error or wrning hs occurred (e.g. full memory, bd sensor, low bttery, etc.). 3.4. Connectors The Instrument hs typiclly five connectors nd screw (when fully equipped), which re rrnged in row on the front of the housing, s shown on Figure 2. These re lbelled, from left to right: SENSOR, RS-232, INTERCON, OPTION, POWER nd (see Appendix B for connector pin-outs). 68mm 32mm Figure 2. Stndrd Instrument, front view Some of these connectors re optionl nd my not exist on every Instrument due to customer requirements. Some connectors support severl optionl hrdwre, which re illustrted in Figure 3. Optionl connections my require third prty devices nd/or services, which my not typiclly be provided by GeoSIG. The stndrd function of ech connector is s follows: SENSOR (Optionl) The SENSOR connector is 7 or 12 pin connector, which is used to connect externl sensor(s) to the

GeoSIG Ltd. GS_GSR_GCR_UserMnul_V21.doc / 18.09.2009 Pge 4 GSR / GCR / AS User Mnul Instrument. It crries the output signls from the sensor(s) nd the test signls from the Instrument. The SENSOR connector provides +12 VDC power to the sensor(s). Different types of sensors with following sensor voltge output rnges re supported: GCR 12 / 16 recorders: 2.5 VDC ± 2.5 VDC AS-12 / 16 nd GSR-12 / 16 / 18 recorders: stndrd: 0 ± 10 VDC (20 Vpp) or 0 ± 2.5 VDC (5 Vpp) differentil optionl: 0 ± 5 VDC (10 Vpp) differentil 0 ± 20 VDC (40 Vpp) differentil RS-232 This connector is typiclly for ttching PC to the Instrument for configuring operting prmeters, retrieving dt or performing system tests. Mximum dt rte is 115 200 Bud. INTERCON (Optionl) This connector llows the Instrument to be interconnected to recording rry. Different types of interconnections my be relised, plese refer to seprte documenttion from GeoSIG. OPTION (Optionl) Two options re supported by the option connector: The lrm option gives two different output signls (rely contcts) to ctivte lrm indictors such s buzzer or flshlights. The connector is lso used to connect n externl time source such s GPS to the Instrument. The signl of this externl source cn be either pulse or n RS-232 level signl. Figure 3. Connectivity Options POWER Through this four-pin connector the internl bttery chrger is supplied with 115/230 VAC power. Alterntively, externl btteries for powering the Instrument my be connected here (with DC Input Option).

GS_GSR_GCR_UserMnul_V21.doc / 18.09.2009 GeoSIG Ltd. GSR / GCR / AS User Mnul Pge 5 (Erthing Screw) (Optionl) This is screw to be used for proper grounding of the Instrument. When used, it hs to be securely connected to relible Erthing. 3.5. Opening the Housing To open the Instrument housing, loosen ll 4 screws locted t the corners (Plese see Figure 1). When ll 4 screws re loosened enough, the housing cn be opened from its bckside. This provides ccess to the inside of the Instrument, which is divided into two interconnected sections, Bse nd Lid, holding the Instrument components under protective covers (Plese see Figure 4). The min ON / OFF switch is plced next to the flt interconnection cble between the Bse nd the Lid. To get ccess to the components, remove ll screws of the relevnt protective cover. Under norml circumstnces, there is no need to remove ny of the printed circuit bord covers inside the Instrument, except for bttery mintennce/replcement. In ny cse, only trined personnel should remove these covers since power enters directly into the Instrument nd cn be dngerous. Moreover untrined ccess my led to serious dmge to the Instrument, s well s my void the wrrnty. Especilly the Lid cover should never be removed without first contcting to GeoSIG or your locl representtive. Before removing ny of the covers, lwys: 1. Flip the min switch to "OFF" 2. Disconnect power supply from the POWER connector 3. Disconnect the min bttery 4. Mke sure tht the green Active Chrge AC LED indictor is off 3.6. Printed Circuit Bords The Minbord is mounted in the Lid under the protective cover nd holds the nti-lising filter circuitry, the A/D converter nd the micro controller prt with rel time clock, memory etc. A second circuit bord my be mounted onto the min bord. This option bord holds the optionl removble memory crd. A seprte circuit bord is mounted to the front inside of the Bse, which termintes the externl connectors, contins the connection for the internl sensor if vilble nd the input protection circuits. 3.7. Internl Bttery The Instrument housing contins typiclly one 12 VDC, 7.2 Ah rechrgeble seled led-cid bttery. The bttery pck provides pproximtely 2 dys of utonomy under norml operting conditions. Additionl bttery cpcity my be dded externlly (for further informtion, plese contct GeoSIG or your locl representtive). 3.8. Internl Bttery Chrger AC powered Instrument only. The built-in bttery chrger will keep the internl bttery pck chrged to n optimum level without the risk of overchrging. The chrger hs sufficient cpcity to rechrge depleted btteries while the Instrument is operting. The chrger is powered by 230 VAC s stndrd nd unless ordered different by the customer. It cn be powered by 115 VAC upon request (for further informtion, plese contct GeoSIG or your locl representtive).

GeoSIG Ltd. GS_GSR_GCR_UserMnul_V21.doc / 18.09.2009 Pge 6 GSR / GCR / AS User Mnul 260mm Fixtion Holes 130mm Bse Cover Min Switch Lid Cover Figure 4. Inside of the Instrument The bttery chrger is just chrger. It is not bttery elimintor. DO NOT operte the unit with only the chrger ttched. A bttery must be connected. For n externl bttery n externl chrger hs to be used. Select therefore chrger with pproprite chrging chrcteristics for the used bttery. 3.9. Externl DC Power Supply DC powered Instrument only. In cse of DC powered Instruments, n externl 15 VDC power supply is connected to the POWER connector. Plese see Appendix B for detiled pinout documenttion. The utilised externl DC power supply hs to be cpble of delivering 200 ma or more t 15 VDC. The ripple of this DC power supply must not exceed 100 mv p-p t 200 ma.

GS_GSR_GCR_UserMnul_V21.doc / 18.09.2009 GeoSIG Ltd. GSR / GCR / AS User Mnul Pge 7 3.10. Test Dt Sheet A test dt sheet issued with the Instrument exctly chrcterises input filter performnce nd other prmeters mesured during production test. Consult GeoSIG or your locl representtive for this sheet if you wish to hve precise specifiction of prticulr instrument. 3.11. Options nd Accessories The following optionl equipment is vilble for the Instrument: Modem Externl or internl modem. This option enbles remote control/opertion of the Instrument vi telephone line. On request the modem cn be mde cpble of "Clling on Event". This mens, s soon n event triggers the Instrument, the modem utomticlly clls pre-set telephone number nd trnsmits the recorded event (optionl). GSM Modem The GSR-18 is lso vilble with n externl GSM modem. With this modem GSR-18 cn send out prmetric informtion of the triggering events in the form of SMS messges. GPS The GPS option is stellite nvigtion receiver ttched to the Instrument. This unit gives the exct informtion bout time nd position of the instrument. Full detils re provided with the GPS option. Plese refer to section 5.5 for more informtion on GPS nd internl clock. Alrm Output This option genertes two lrm signls (for two threshold levels) in wy similr to tht of the recording trigger, thus llowing the personnel in chrge to be informed immeditely on the severity of strong event. The outputs re 2 rely contcts; either normlly open (NO) or normlly closed (NC) (to be specified t order). The mximum voltge to be controlled by the relys is 24 VDC t mximum current of 100 ma. Memory upgrde The internl memory module cn be expnded up to 2 Mbytes on GCR-12 / 16 nd up to 128 Mbytes on GSR-12 / 16 / 18. No memory is implemented in AS-12 / 16, thus no upgrde is possible. Removble Memory Crd GSR instruments hve specil A version. These instruments hve built-in interfce for using ATA Compct Flsh Memory Crds (JEIDA/PCMCIA) up to 2 Gbytes. DC Chrger The DC chrger enbles the user to chrge the system off single 12 VDC source. This is useful if it is necessry to chrge the system by single 12 VDC externl bttery. 3.12. Storge When not in use, the Instrument should be stored t norml room temperture in dry loction. This will help to mximise the bttery lifetime. If the instrument (recorder) is stored for more thn few weeks, the Instrument should be ttched to VAC power for 24 hours to top off the bttery chrge. In this cse you should remove ll dt records from the memory. Note tht the rel time clock continues opertion even when the min switch is in the OFF position. Therefore, unless the clock is turned off by disconnecting the min bttery cble, the Instrument will require occsionl rechrging. Rechrging for 24 hours every 2 months is recommended. In the event of bttery filure, the memory nd the rel time clock re mintined by lithium bttery.

GeoSIG Ltd. GS_GSR_GCR_UserMnul_V21.doc / 18.09.2009 Pge 8 GSR / GCR / AS User Mnul 4. Instlltion, Configurtion nd Opertion This section lists the procedures involved in instlltion, configurtion nd opertion the Instrument. The procedures will be outlined s steps to be performed in the field or in house prior to deploying the instrument in the field. 4.1. Site Selection 4.1.1. Environmentl Considertions The choice of n instlltion site for seismic event recorder is similr in most respects to tht of regulr continuous recording seismic sttion. Although the Instrument is housed in solid, wetherproof cse, it is certinly best if loction cn be rrnged for the unit, which is free from direct sunlight, precipittion, the dngers of flling mterils in the event of severe erthquke nd the risk of tmpering or vndlism if the unit is to be left unttended. There re lso specil considertions for event recorder instlltions. It is importnt to select the site nd set the trigger level to void unwnted dt recording, such s vibrtion from mchinery, highwy trffic, ircrft, wves, etc. It is wise to check the instrument frequently during the first severl dys of opertion fter ech set-up, to see if there re previously unsuspected sources of noise which re triggering the instrument nd using up the memory. In ddition, the user should select site with provision for 115 / 230 VAC power if the unit will be left in plce for long period of time (more thn 3 dys). Although this is not necessry for the opertion of the device, it does preclude concerns bout bttery chrging. You should mke note t this point of ny culturl or environmentl sources of noise nd vibrtion round the selected site, which my cuse flse triggers of the recording mechnism. These will hve to be considered when setting the trigger prmeters. 4.1.2. Power Supply Considertions The Instrument my be powered from 115 / 230 VAC supply, from the internl bttery, or 12 VDC externl supply such s n utomotive bttery or solr pnels (optionl). If the supply in the field will be from 115 / 230 VAC supply, you need to connect the VAC cble from the Instrument to the power source only. The Instrument opertes continuously, providing trickle chrge to the internl bttery. The VAC supply must consist of Phse, Neutrl nd Protection Erth. If the supply will be exclusively from the Instrument s internl bttery, it is necessry to chrge the bttery sufficiently beforehnd. Mke sure to hve t lest 24 hours of uninterrupted chrging prior to leving the Instrument in the field. The configurtion of the instrument, of course, my be performed while the chrger is connected to the Instrument. The Instrument hs to be plugged to 115 / 230 VAC for chrging the internl bttery. The best pproch to the deployment of the Instrument is to use the internl bttery long with the VAC power t the remote site. In the lb, the Instrument cn be checked nd configured for the correct time, trigger nd other relevnt settings. It my then be crried to the remote site (with the power switch in the "OFF" position to conserve the internl bttery) nd then connected to the VAC power. After switching to "ON", the Instrument runs with the pre-configured prmeters. This reduces the mount of time needed to configure in the field; n importnt considertion in the cse of n dverse condition.

GS_GSR_GCR_UserMnul_V21.doc / 18.09.2009 GeoSIG Ltd. GSR / GCR / AS User Mnul Pge 9 4.2. Instlltion Mny times the loctions of seismic equipment re highly exposed to electricl disturbnces cused by lightning or by the industril environment. Although the Instrument contins over voltge protection, it my sometimes be necessry to use dditionl surge protectors for the equipment. Contct GeoSIG or your locl representtive for more informtion. 4.2.1. Supply Voltge Selection AC powered Instrument only. The Instrument my be powered from 115 VAC up to 230 VAC, 50 or 60 Hz. The Instrument contins power supply with trnsformer, which hs to be configured properly to function with either 115 VAC or 230 VAC. 4.2.2. Connection of Externl DC Power Supply DC powered Instrument only. The DC powered Instrument cn be powered from n externl 15 VDC power supply through the 7 pole POWER connector. Plese see Appendix B for pinout informtion. The externl power supply hs to deliver minimum of 300 ma t 15 VDC. 4.2.3. Requirements for the Instrument Foundtion Minimum surfce re requirements with internl sensor: with externl sensor: with externl sensor nd interconnection: 50 x 50 cm 50 x 75 cm 50 x 100 cm Height requirements Minimum surfce re specifictions indicted bove re only pplicble up to height of mximum 25 cm. Foundtion dimensions should be expnded in ech direction proportionlly by incresing height. Anchorge requirements Foundtion hs to be very well nchored or dhered preferbly to rock or concrete bse. In cse of need for foundtion on soil, concrete cubicle of 1 m 3 hs to be cst in the ground to serve s bse. 4.2.4. Mounting the Instrument The following re the typicl items needed for instlltion: Instrument Power Cble RS-232 Cble This Mnul nd its Appendix Set of Tools 4 x M6 x 40 mm bolts with concrete nchors Lptop PC with GeoDAS instlled, to check or configure the Instrument Any ccessories or peripherl equipment for the Instrument nd their mnuls, such s externl sensor, GPS, externl modem, etc.

GeoSIG Ltd. GS_GSR_GCR_UserMnul_V21.doc / 18.09.2009 Pge 10 GSR / GCR / AS User Mnul If the Instrument hs n internl sensor, wter level with minimum 2 degrees ccurcy is lso needed for correct levelling. In cse of using externl sensor, refer to the sensor mnul for mounting. Typiclly follow these steps for successful instlltion: The Instrument cn be mounted in ny convenient position t the loction tht complies with the bsic requirements outlined in section 4 upto here. Plese note tht in cse of n internl sensor, orienttion of the sensor would define the positioning of the Instrument. Mke sure tht fter instlltion there is enough spce to esily open the Lid nd ccess inside the Instrument s well s esily connect / disconnect ny of the connectors. Also mke sure tht the visul indictors on the top of the housing, i.e. the LCD nd LED s, re visible fter instlltion. Open the Instrument housing (see section 3.5) Fix the Instrument with the 4 x M6 x 40 mm bolts to the concrete nchors through the fixtion holes t the corners of the housing (see Figure 4). If the Instrument hs n internl sensor, mke sure tht the Instrument, or the internl sensor is properly levelled using the levelling mechnism supplied within the sensor or the Instrument. If no levelling mechnism is supplied, mke pproprite foundtion rrngements tht the Instrument is levelled to minimum of 2 degrees from level. Depending on the loction it my be necessry, to erth the Instrument properly. Therefore connect the (Erthing Screw) of the Instrument vi copper wire of minimum 1.5 mm 2 to proper erth contct. It is strongly recommended to hve proper Erthing. 4.2.5. Optionl Interconnection When optionl Interconnection is purchsed, specil hrdwre nd softwre instlltions hve to be followed. Further detils on Interconnected Recording Networks nd their instlltion re given in the GeoSIG technicl note, TN # 85: Strong Motion Instrumenttion Networks s well s the "Appendix G" of this Mnul. Plese refer to these documents to be ble to properly deploy such network. 4.2.6. Terminting the Instlltion Fix the remining cbles, so tht they my not influence the sensor signl by knocking or vibrting t the sensor. Do not leve ny unpowered device connected to the Instrument. After verifying tht the physicl instlltion is done properly, the Instrument cn now be strted nd put in opertion s described in the following sections. Do not touch the sensors nd leve the instlltion site s quietly s possible.

GS_GSR_GCR_UserMnul_V21.doc / 18.09.2009 GeoSIG Ltd. GSR / GCR / AS User Mnul Pge 11 4.3. First Strt 1. Connect the power cble to the POWER connector. 2. The green AC LED indictor must turn on, If not: In cse of AC powered Instrument: Disconnect the power cble from the Instrument. Open the Lid of the Instrument (refer to section 3.5). Check if the internl FUSE is blown. If so, then replce it with 500 ma slow blow fuse. Check if the AC power is present t the plug. In cse of DC powered Instrument: Check the power supply to the Instrument nd the cbling. Check the power delivery from the power supply in ccordnce with section 4.2.2. 3. When the problem is solved, reconnect the power cble to the Instrument. 4. Open the Lid of the Instrument (refer to section 3.5). 5. Insert the memory crd if pplicble. 6. Flip the min switch to its ON position. The green RUN LED flshes once per second during the "Turn-On Dely" time (defult 15 seconds). Afterwrds it chnges to one pulse every two seconds. This indictes tht the instrument is running. Do not move or vibrte the sensor during the power up cycle. The Instrument is clculting the bseline of the incoming signls; ny noise could distort these signls. You cn now configure the opertion prmeters, strt dt cquisition or leve the Instrument for opertion with the ctul configurtion s described in the following sections. 4.4. Configuring Prmeters nd Putting in Opertion For configurtion nd dt cquisition PC running GeoDAS hs to be used. For the instlltion nd usge of GeoDAS refer to the GeoDAS Mnul, which explins the use of the softwre in full detils. The typicl procedure to be followed is to connect the cble from the PC to the RS-232 Port of the Instrument nd follow the steps described in the GeoDAS Mnul to configure or perform following functions: Login to nd Communiction with the Instrument. Verifying the opertion of the Instrument nd its sensor vi Anlog Signls. Setting Dte nd Time. Sving nd/or Loding Configurtion File. Setting Recording prmeters Retrieving nd Mnging files 4.4.1. Seril Dt Output Only in GSR-18 delivered with Seril Dt Output option. With this option enbled, the Instrument will send out seril dt strem through the RS-232 connection when the user logs out. As soon s GeoDAS is used to login, the Instrument stops the dt output. The seril dt strem of the Instrument contins ll three chnnels. Depending on the configurtion tht hs been set vi GeoDAS, it is possible to enble or disble the seril dt output nd select between two modes of opertion: Smple Oriented Mode (SOM): After logout, every smple is sent to the communiction line.

GeoSIG Ltd. GS_GSR_GCR_UserMnul_V21.doc / 18.09.2009 Pge 12 GSR / GCR / AS User Mnul Pcket Oriented Mode (POM): After logout, every second one-second buffer is sent to the communiction line (GSBU GeoSIG / Bergen University protocol). For recording nd nlysing on the PC, besides GeoDAS, dt cquisition softwre SEISLOG, nd dt nlysing softwre SEISAN cn lso be used. Plese refer to the web site of University of Bergen: http://www.geo.uib.no/seismologi/softwre/softwre.html for further nd up to dte informtion on these softwre. 4.4.1.1. Smple Oriented Mode (SOM) Set-up: Connect the cble from the PC to the RS-232 connector on the Instrument. Log in to the Instrument. Plese refer to the GeoDAS mnul for further steps. Strting the seril dt mode: After logging out, the Instrument strts utomticlly the seril dt mode fter 2 seconds. Stopping the seril dt mode: After logging in to the Instrument, the seril dt mode utomticlly stops nd remins off for the time being logged in. Dt formt: 8 bytes re sent with ech smple to the COM port: Byte 1, sync byte: Byte 2, dt byte 1: Byte 3, dt byte 2: Byte 4, dt byte 3: Byte 5, dt byte 4: Byte 6, dt byte 5: Byte 7, dt byte 6: Byte 8, Aux. byte: 0xyy (user progrmmble with the communiction progrm) x high x low y high y low z high z low Prity check of the bove dt bytes Dt formt is signed binry (2s complement, 16 most significnt bits). Prity check byte is defined s in Tble 1. Tble 1. Definition of the prity check byte 0b 00xx xxxx +--- Bit is set, if dt byte 1 hs odd prity +---- Bit is set, if dt byte 2 hs odd prity +----- Bit is set, if dt byte 3 hs odd prity +------ Bit is set, if dt byte 4 hs odd prity +-------- Bit is set, if dt byte 5 hs odd prity +--------- Bit is set, if dt byte 6 hs odd prity Bud Rte: The trnsmission bud rte depends on the settings mde vi GeoDAS (refer to the GeoDAS mnul for further explntion). Avilble rtes re listed on Tble 2.

GS_GSR_GCR_UserMnul_V21.doc / 18.09.2009 GeoSIG Ltd. GSR / GCR / AS User Mnul Pge 13 Tble 2. Possible bud rtes with seril dt strem Communiction speed POM, 3 chnnels 100 SPS X X 200 SPS X 250 SPS X SOM, 3 chnnels 100 SPS X X X X 200 SPS X X X 250 SPS X X 1200 Bud 2400 Bud 4800 Bud 9600 Bud 19200 Bud 38400 Bud 115200 Bud 4.4.1.2. Pcket Oriented Mode (POM) Set-up: Connect the cble from the PC to the RS-232 connector on the Instrument. Log in to the Instrument. Plese refer to the GeoDAS mnul for further steps. Strting the seril dt mode: After logging out of the Instrument, it strts utomticlly the seril dt mode fter 2 seconds. Stopping the seril dt mode: After logging in to the Instrument, the seril dt mode utomticlly stops nd remins off for the time being logged in. Dt formt: Stndrd GSBU protocol is used. The Instrument cn be directly connected to GeoDAS or SEISLOG in the Pcket mode, which increses the performnce regrding event memory, event detection nd online (GeoDAS, SEISLOG) nd offline (SEISAN) nlysis enormously. If SEISLOG is used plese go through the SEISLOG mnul to look up the settings required for the Instrument. 5. Functionl Description This section discusses some of the technicl detils of how the Instrument works. Input signl filtering nd digitising, triggering, time ccounting, dt storge nd event logging re mong the function described. 5.1. Signl Conditioning Electricl signls from seismic sensors connected to the Instrument re rnge-djusted in preprtion for conversion to digitl form nd re filtered to prevent lising effects. The signls re next smpled nd digitised, nd then digitlly filtered under softwre control to further reduce noise. Then these dt re used for triggering nd recording. The Instrument ccepts signls from sensors within the sensor voltge output rnges s follows: GCR 12 / 16 recorders: 2.5V ± 2.5 VDC

GeoSIG Ltd. GS_GSR_GCR_UserMnul_V21.doc / 18.09.2009 Pge 14 GSR / GCR / AS User Mnul AS-12 / 16 nd GSR-12 / 16 /18 recorders: stndrd: 0 ± 10 VDC (20 Vpp) or 0 ± 2.5 VDC (5 Vpp) differentil optionl: 0 ± 5 VDC (10 Vpp) differentil 0 ± 20 VDC (40 Vpp) differentil The Digitl Vlues (DV) for Anlog Input Voltges (AIV) re summrised in the following tbles: Tble 3. DV nd AIV for GCR Instruments GCR Instruments Digitl Vlue DV [Bit] Anlog Input Voltge AIV [V] GCR-12 GCR-16 Minimum input 0.0 0 0 Zero input 2.5 2 048 32 768 Mximum input 5.0 4 095 65 535 Tble 4. DV nd AIV for GSR nd AS Instruments GSR nd AS Instruments Digitl Vlue DV [Bit] Anlog Input Voltge AIV GSR-12 GSR-16 [V] AS-12 AS-16 GSR-18 Minimum input FS 2 048 32 768 131 072 Zero input 0.0 0 0 0 Mximum input +FS +2 047 +32 767 +131 071 FS is the full-scle input rnge of the instrument nd tkes the following vlues depending on the input configurtion: Tble 5. Full Scle Input Rnge of the Instrument Differentil input FS [V] 0 ± 2.5 V (5 Vpp) 2.5 0 ± 5 V (10 Vpp) 5.0 0 ± 10 V (20 Vpp) 10 0 ± 20 V (40 Vpp) 20 In GCR Instruments ech signl chnnel hs low-pss 100 Hz 6th-order Butterworth nlog filter. The sensor input signl psses through this filter prior to being smpled nd converted to digitl form. This filter removes signl energy t frequencies bove one-hlf the input smpling rte (1000 Hz) so tht these higher frequencies re not lised by the smpling process, ppering s erroneous digitised dt. The signl level bove 400 Hz t the output of the nlog filter is t lest 72 db below the input level. 5.1.1. Digitl Signl Filtering 5.1.1.1. GSR / AS Instruments The nti-lising low-pss filter is utomticlly pplied by the sigm-delt A/D converter bsed on the selected dt output rte. For 200 SPS the filter cut-off frequency is 50 Hz nd for 100 SPS it is 25 Hz. The trnsfer function with the liner phse response (FIR) hs (sin(x) / x) 3 form tht provides greter thn 100 db rejection t the notch frequencies. The reltionship between the progrmmed cut-off frequency nd the first notch is constnt (f NOTCH = 3.81 x f CUTOFF ). The first notch frequency is lso the output smple rte. Knowing exctly wht hppens to the dt during the recording process fcilittes compenstion clcultion nd helps ctully to get more precise understnding bout the site behviour. Since the

GS_GSR_GCR_UserMnul_V21.doc / 18.09.2009 GeoSIG Ltd. GSR / GCR / AS User Mnul Pge 15 delt-sigm trnsfer functions re stble nd well defined, Instrument impcts cn be virtully eliminted by knowing the exct trnsfer functions. The trnsfer function in terms of the z-vrible is: ( ) Hz 1 1 z = N 1 z The AD7716 is 22 Bit A/D converter on the bse of sigm-delt pproch. The Resolution is 22 Bit nd the usble dynmic rnge is up to 111 db RMS. On the GSR-18 bord the usble dynmic rnge t 100 SPS is 111 db RMS nd t 200 SPS 108 db RMS. The AD7716 bsed Instruments show temperture drift of 1 digitl count per K, for the spn, which is less thn 0.002 % / K, or less thn ± 0.0015 % over the temperture rnge of -10 C to 60 C. The bis or offset is even better, e.g. less thn 1 digitl count per K. Chnnel to chnnel skew is zero since the AD7716 hs four independent converter chnnels. AD conversion nd the signl processing is the sme for ll the Instruments with the difference tht the resolution of the smpled dt is either 12 or 16 bits for GSR-12 / 16 n AS-12 / 16 N 1 3 5.1.1.2. GCR Instruments The mplified nd filtered nlog signls re smpled t rte of 1000 SPS per chnnel nd converted by successive-pproximtion AD converter to 16 Bit digitl dt vlues. Since the Instrument llows recording with output smple rtes of 50, 64, 100, 125, 200, 250, 400, 800, nd 1000 SPS the dt hs to be further decimted digitlly. The digitised dt still contins signl energy t frequencies of up to 500 Hz, which hs to be filtered digitlly for ll smple rtes except 1000 SPS. The filter type used is 6 th order Butterworth. At the Nyquist frequency (hlf the decimted smple rte) the signl is t lest 84 db below the input level due the combined effect of the 100 Hz nlog filter nd the digitl filter. Since dt re digitised nd stored t 16 Bit resolution, signls bove the Nyquist frequency, even full-scle signls, do not ffect the finl stored dt vlues t ll. It is importnt to note tht every filter introduces phse shift to the dt. The phse shift of the digitl filter is -270 t the cut-off frequency. This is due to the fct tht it is 6th order filter with ech pole contributing 45 of phse shift t the cut-off frequency. 5.2. Triggering Any of four methods my be used to trigger the Instrument to strt recording dt: The Instrument my be set to trigger internlly when incoming sensor signls stisfy certin criteri. The Instrument my be set to strt recording t specific time. The Instrument my be set to strt recording by softwre commnd from connected PC. A trigger signl my be provided from nother Instrument or other externl source (with externl trigger/network option). Recording strts the pre-event time before trigger, continues s long s the trigger criterion re met nd stops fter the post-event time.

GeoSIG Ltd. GS_GSR_GCR_UserMnul_V21.doc / 18.09.2009 Pge 16 GSR / GCR / AS User Mnul Trigger Pre-Event Event Post-Event Time Figure 5. Typicl Recorded Dt for 1 Chnnel If the user sets up trigger prmeters tht re continully met by the environment, the system will trigger continuously. This will be indicted by the yellow event LED which is lwys on. The user cn connect PC to the Instrument unit to interrupt the recording nd select different set of trigger criteri. 5.2.1. Internl Triggering Internl triggering requires tht incoming sensor dt stisfy certin pre-set criteri for recording to begin. The digitised nd digitlly filtered sensor dt re used s input to the internl triggering system. Either of two criteri my be used for internl triggering. The Threshold Trigger simply determines if the signl mplitude hs exceeded pre-set threshold. The Short Term Averge/Long Term Averge (STA/LTA) Rtio Trigger determines if there is sudden increse in signl mplitude. A combintion of both Threshold nd STA/LTA triggers my lso be selected so tht the Instrument will strt recording when either trigger criterion is met. 5.2.1.1. Threshold Trigger The Threshold Trigger compres the signl mplitude of the filtered trigger signl to threshold vlue. The sensor dt re first processed by digitl high-pss filter with corner frequency of bout 0.1 Hz to remove ny DC offset. The dt re then filtered nd rectified to give n bsolute-vlue signl mplitude rnging from 0 to mximum of 2048. Dt recording is initited when the mplitude exceeds the pre-set threshold vlue. The user my enter the threshold vlues in the selected chnnel unit. GeoDAS clcultes it to rw counts (LSB) nd puts the vlue into the recorder. If the threshold is set to 10 counts, then signl greter thn 10 counts will cuse trigger. The stndrd GSR-18 hs the following trigger filters: Low-pss filter of 2 nd order Butterworth filter with corner frequency t 12Hz. High-pss filter of 2 nd order Butterworth filter with corner t 0.1Hz. These filters re used simultneously (not individully) nd cn be turned on nd off in GeoDAS. 5.2.1.2. STA/LTA Rtio Trigger The STA/LTA rtio trigger uses n lgorithm, which will filter out bckground noise nd llow only those dt, which pss through its filters to trigger the record function of the Instrument. This filter method uses Long Term Averge of dt inputs to set the bckground noise bse level nd compres this to Short Term Averge of dt which is more responsive to chnges in the dt input strem. During the stedy stte of the system, the STA nd the LTA will be nerly equl. The shorter the STA verging period, the more quickly it will chnge with the input. The trigger condition occurs when the rtio of the STA versus the LTA exceeds present level, ALPHA. The probbility of hving flse trigger due to noise will be minimised if long STA verging time is selected. Obviously, the STA should not be chosen longer thn the shortest event of interest. In ddition, the STA should be shorter thn the block of pre-event dt stores in the Pre-event Memory. If not, the initil portion of n event my not be recorded.

GS_GSR_GCR_UserMnul_V21.doc / 18.09.2009 GeoSIG Ltd. GSR / GCR / AS User Mnul Pge 17 If the LTA is llowed to updte during the event, nd the event is long reltive to the length of the LTA period, then the instrument will determine tht the event is ctully prt of the bckground noise nd the trigger condition will terminte. The user hs the option of enbling or disbling the LTA updte. 5.2.2. Time Triggering The Instrument my be set up to begin recording dt t predetermined times. Up to four dtes nd times my be progrmmed into the unit during set-up. A recording durtion for ech recording time is lso specified. Once set, the Instrument uses its internl clock to keep trck of the dte nd time-ofdy until reset gin. 5.2.3. Softwre Triggering The Instrument my be set up to begin recording dt by commnd of the connected PC. The progrm supports triggering by key stroke. If the Softwre Trigger in the Trigger Settings window is enbled, you my strt recording by clicking Trigger Now in the Directory of Instrument Files. The Instrument records Pre- nd Post Event Time. This feture is useful for mesuring seismic noise levels. 5.2.4. Externl Triggering (option) The Instrument my be externlly triggered by connecting trigger signl to the Interconnection connector (option). The externl signl my come from nother Instrument recorder, from Control Centre or from some other source. The Instrument begins recording dt when the externl trigger signl goes to low (0 V) on flling edge. Severl dt recorders my be connected in "bus" fshion nd triggered simultneously by one trigger signl. Whenever it is triggered, regrdless of trigger source, the Instrument puts out signl on the Mster/Slve connector to be used s trigger by other units, e.g., one Instrument my be set up to trigger internlly on incoming sensor signls, nd cn then ctivte severl other units to begin recording. 5.3. Triggering Guidelines It is importnt to note tht the input signl for the trigger chnnel is digitlly high-pss filtered to remove ny DC offsets. The digitl high-pss filters hve corner frequency of pprox. 0.1 Hz. 5.3.1. Threshold Trigger The threshold trigger compres the digitlly low-pss filtered nd rectified input (sensor) signl with the vlue of the threshold level in the Trigger menu. The corner frequency of the filter hs to be set in the Filter menu. 5.3.2. STA/LTA Rtio Trigger The STA/LTA (Short Time Averge/Long Time Averge) rtio trigger computes the short term nd long term verges of the rectified input (sensor) signl. When the STA exceeds pre-selected multiple of the LTA, the GSR begins to record dt. The dvntge of this trigger type is tht the trigger sensitivity dpts to the seismic bckground signl. With n incresing noise level the trigger sensitivity decreses nd therefore less flse triggering occur. To use the STA/LTA rtio trigger, four following informtion must be supplied: the short term time period the long term time period the rtio db of short term verge to long term verge which will trigger recording if you wnt to hve the vlue of the long term verge updted during n event.

GeoSIG Ltd. GS_GSR_GCR_UserMnul_V21.doc / 18.09.2009 Pge 18 GSR / GCR / AS User Mnul The verge time for the STA nd LTA my be set s follows: STA 0.1 to 10 seconds LTA 1 to 100 seconds The LTA my not be set smller thn the STA. The rtio of STA to LTA, ALPHA, is defined s: STA ALPHA = 20 log10 LTA The probbility of hving flse trigger due to noise cn be minimised if long STA verging time is selected. Obviously, the STA should not be chosen longer thn the shortest event of interest. In ddition, the STA should be shorter thn the block of pre-event dt stored in the Pre-event Memory. If not, the initil portion of n event my not be recorded. The verge period for the LTA should be chosen short enough to dpt to ny chnges in the level of bckground noise. However, the LTA time should be long compred to the STA time, otherwise, the LTA will dpt to n event s if it ws simply chnge in the bckground noise level. Plese note tht it is possible to select combintion of STA, LTA nd ALPHA, which will not meet the trigger conditions, nd no internlly generted trigger will occur. For exmple with STA = 1.0 LTA = 10 ALPHA = 23 db the STA/LTA rtio of 14.125 (23 db) never could be reched becuse the LTA dpts to the signl before the STA vlue gets to the trigger level. In this cse, the theoreticl mximum vlue for ALPHA would be 2048 ALPHA = 20 log10 = 20 db 205 This would indicte tht ny vlue of ALPHA greter thn 20 db could never be used for ny LTA period/sta period rtio equl to 10. Some smple STA/LTA vlues nd the gretest possible ALPHA tht would llow trigger re given herefter. Tble 6. Mximum vlues of ALPHA for some smple STA/LTA rtios. STA LTA Mximum ALPHA 2.0 10 14 db 1.0 10 20 db 0.5 10 26 db 0.5 20 32 db 0.2 20 40 db If the LTA Updte is enbled, the long term verge vlue (LTA) will be periodiclly updted even during n event. The recording of long event could be cut off since the LTA vlue increses until the rtio of STA/LTA hs reched vlue where the trigger condition is no more fulfilled. With n dequte "Post-Event Time" the loss of dt cn be minimised. If the LTA Updte is disbled, the long term verge vlue (LTA) will be "frozen" during recording. With permnent seismic noise signl where the input signl does not decrese for long time, the short term verge vlue (STA) will no more rech vlue below the trigger level ny more fter triggering. The GSR will not stop recording until its memory is full. Therefore it is recommended to hve the LTA Updte "enbled" for stndrd pplictions. Three exmples of typicl pplictions nd the suggested trigger prmeters re given below