- 107 -

ACTA ~ONTANA 1992Series A, No. 2 (8,8), 107-120

TH~ TESTING OF INPUT DATA FOR THE DETERMIN~TIONOF ROCKBURST FOCJ\L tlECHANISHS

~ VlasLa VESELÁ and a Lubom1r STA S

a tlining InsLiLuLe oE Czechoslovak Academy of Sclences708 00 OsLrava-Poruba. StudenLská 1768, Cz€choslovakia

Abslract:The program for Lhe delermtnaLion of rockbursLs Eocal mechanism

have been modify to comply wiLh Ostrava - KarvlnA Co~l FieldcondiLions.

lnput daLa from seism!c neLwork of Seisllllc PolygonOstrava - Karviná Coal Field and 10eal seismic neLwork Lazy Colliery",as Lesled to influence of accuracy of Eocus coordinales and inpulvalues of ampJ iLude motion, seismic medium mode 1, crilerion ofnptimization.

Key \lords:Oslrava - Karviná Coal Field, rockbursl focal mechanism, ampliLud~inverse met-hod.

1.INTRODUCTION

Lasl year ve began to sludy lhe rockbursLs focal mechanismgeneraLion meLhod in easLern part of Ostr.ava - Karviná Caal Fleld(Ka 1áb. staš, Vese lá, 1992). Our meLhodology is based on experiences ofresearch workers of GeoLechnical InsLiLuLe and Geophysical InsliLute ofC2Bchoslovak Academy af Scienees. We used a compuler program forc"mplilude inverse melhod (Šilen}", 1987) We had lo revise lhis program~nrl we LesLed the rlghlness dependence of results on accuracy of inpuLdi'lta.

The progrdm for deLerminaLion of Lhe rockbursLs focal mechanism,tJsi ng a mp l i t.uďe Inverslon meLhod have besn creaLed in Geophysi~alInst.ituLe of CZBchoslovak Academy of Sciences, Prague. The theor~l!caJ

Lhe ro~kbu.sLs focus 9uPPo91ng a superposilion of Ghear and

- 108 -

volumeLric componenl of focal mechanlsM Is used (Šllen9, 1987).

Th~ calculaLíon is performed frorn lhe P-wave f1re exLrem~amplitude Molion r€corded on seismic sLaLions and direcL or head vaV2propagaLinq along a seismic ray.

The origlnal version of Lhe program dealL only vlth two-layerseismic medium model (four-layer model could be used after Lhernodlficalion, ILs calculaLlon vas inLerrupled) and with InpuL daLa fromSllrface selsmic slaLlons. Oving to lhe complexiLy of the selsmic mediumin Lhe easl parL of Dstrava - Karviná Caa) Fleld and the presence ofunderground sLaLians in lhe selsmic nelvork covered in Lhis area, lheproqram vas complelely revised. Updale verslon of lhis program dealeullh maximum len~laye~ selsmic medium model and enables to usa dalaCrom underground moreover surface seismic sLaLlons.

Numerlcal characLerislics of Lhe rockbursl foca! mech~nism (dip,sLrlke, rake, volumeLric comp.) and dravlng of Lha projecLion of nodalsurface and poslllon of Lhe sLaLion lo lower hernlsphere of unit sphereare lhe oulpuls for lhls program. The ouLpul can ba added lhen by basiedescrlpLion dala of selsmic event (name, dale and Lime, energy, etc.)and olher supplem~nlary informaLion aboul lhe seismlc event in a formof Lhe lable. Now Lable conlains lhe following data: stan - ndme af theslaLion, chs - charac~eristic of the slallon (underground, surface).Ax, Ay, Az, AL -charLered componerits of ampllLudes, aha way ofcalculalion to slandard amplilude Ared, kh lype of vave (O - dlrecL,h~ad) a - angle devialion beLveen rea! and ealeulaLed dlrecllon of ray,nxf, pzf - angle of va ve propagaLing from focus, xysf - epicentraldislance of focus, dL hypocenLral dislance of focus, ~l lotal rayPdLh. r! palh of vave on boundary line, Lime lima of propagallng,csn cosinus of ray direclion lo the slaLion, n.ull usarlallenuaLion. ?xxx7 value of square theorelic and standard measuredampliludes dlfference after flnish calculatlon (See Flg.t), (Kaláb ela 1 . , 1991) .

We began using modified program for routlne elaboraLion of selsmlcdata and our resulls complied ln general vith geomechanical ideas(Kaláb, 1991). bul in sama Casas ve had differanl resulls for tne samaevenl afler the repeaLed calculation vlth changed input condilions.Thal Is ve declded lo check aga!n Lhe conducL of lhe program. WB used~ sel of selsmic records of exploslve vorks of large exlent (velghl afcharqe more than IOOOkg), iLs selsmlc energy vas delermlnad to ba morelllan IK103J and mlnjnq Lremors wllh selsmic energy more Lhan 104 J.recorded by llle sLaLions of Seismie Polygon OsLrava - Karvlná Caa1

íleld and of Iaea! seismicThe focus coordinalas

neLwork Lazy Colllery (Fig. 2).of aII seismic events vas calóulaled in

24.2.91 15:31:27sit.l utlum:

E= H:455150.n 65 t n=O

1101340. 630.dH:model.2

!DSRIJCl.:2) (12.5.80.6) 39.2. 177 .7) 130.8. 81.7) .708E-Ol Fmin .769E+QO~t ••n?C~ AI( __ ~ •...__ .\:: __ At. ---c""'- A<-'od ~ 1< ••• Olllf <;o 3:rf =- lCVOf' _ ct':: __ tI __ ,.1 .~ tiu3 _ cm> _ n.o.ItJ _ ?taa? ••..•1"'~ I \.1...0.2 1-2.2 t •. t.t>!'i I I "'" .4-ZZ;:-Ol1 0\ ~1.1191.'l1 <r3.21 5-42!S.1 ::-447.1 ~.I 0.1 .llE+Ot!-.OO'Inb\ .~~....all .1251<;-<>111l~ 1 t.l~."'2 1-q..04 '''2.3''1 I 1 ]01>1' .1~..oo1 01 8612\<;1.717.2.:1 :N70., :l9íl.1 3~fTJ.l o., .Q-:'S;:+OOI-.vl77':i! .4041<:0-01\ .lt2E-o:sa~IO I LI+U •..l 1.2.93 1+'3.1.7 I I '''11 .1:11"«>0\ 01 4:51'247.'1\ 'l'2.:51 ~.I :s:oaq.1 ~~.I o., .IID'.O:+OOl-.ó43:l1\.~'·(HI .~-0'2a11~ I I.I+-:S.a '''2.č.7 I~.:§:l I I •••\ .Q7"5E-O\j 0\ BlI231.21 04.3\ 4:na.! 4J.C.J.1 4~.:s.1 0.1 .l~.oll-.()Q:pJ,.1 .~~+Oll • .:rtU:-Q'21122 11.1..0.73 '''2.::3 1~_S3 I I ••••' .1401i+OO1 CI "'21~.11 'n.21 !:'219.l !i2:2::!.1 ~.J o., .12l<...o11-.~1 .~+Oll .~-()'2i1l1.l I J.I.'.0 ' •.J.-:;:J 1~.4 1 1 ••• ' .10i'i'-OO1 01 ~1:Z«.11 ~:l.• 1 .n-\.I 4::s33.1 .•.r;;:!.1 0.1 .1Cl4.o()ll-.O..I.~::;1 .4./12E"'<l11 .4~2i~11ZN'>I ').\-1.72 1-1.7:1: 1~.12 1 1 ul .le«...ool 01 lZO:.:21 '?'J.Ol '5~.1 ::5677,\ 51\Tl,1 0.1 ,1:U;<toQll-.1~201 ,~-.(Il' .4(l7'i-o.:nHlA'.' t 0-1-0." 1-0.:3 l-l.::.::::l 1 1 :ul .;:....41<-011 11 !t'n •.q ss.vt '1004.1 ~.o.l lOi.Oá.l !1'M7.1 .~"(Hl- . .l4O:s:Il .1~+O::!1 .:;:e&~1JOif) 1 O.I+O.l!i !-O.i2 1-1.1-' 1 I ul .:.o.3F.-.)II'l\ \1~.11 :5!5.~1 100:;2.1 1~.1 1~.1 61W!~1 .23{L+<)11 ••.•~1 .10TE.t421 .~-<HItLUT 1 O.I-l.;>~ l+l • .:.:J 1-~.ft2 I I Ul .41 ..••&:+00101 13.07.91 'jI{ ••• ~1 70.:>0.1 70G't.l 70Q0oI 0.\ .11C::"<l11-.ilq~1 .n.u:;+011 .12Z.li+OO~U"'RS \ (I.I"'\,;> j*l.q \-7.:;::S: I \ ul .:b.3E~1 11 I ::3.71 ~.q, ~.Q,.I Br ...••• I ~.I "'57'7.1 .ace-ott- • .=:.J.O:l51.a71E+<l11 .7~-OHl1n~ 1 :>.1·".:::5 \0.0.6. 1•.21.~ 1 I ;u;!-.·Il.n:...oo\ 01 I ~.:;l 're.-41 1>107.1 b173.1 bl73.1 0.1 .1~!::.o.Q~1-.1«-1l1 .~+Otl .':OOI:í:+-OOtHr"l I <,).1-Q.2 !--.t.2 1't'().0t1l I 1 u\-.4,,~-o11 21 127L1\ :.0.41 2!lM2.\ ~7.1 27006-1 lIo7~.1 .S2!i:"'O\I.....t.s7271 •.L<nE+<n:\ .~~1~IZI, 10.\ 1 I-tO. I 1 ul .'::t.1I'.0-00101 I3.:«).úl100 •.I,\ iI~.1 :!G40.\ :}Q-(l().l 0.1 • 12ii...oll-. l00HoI . .=l1b1<:H}t!.153E-021I:I~ 10.1 \ I-G.I 1 1 ul .1:...t"EH)Ol CI 1237.U10'~.i.! 4O'!.B.l 4\!\9.! o\l!?1.1 0.1 .?<'It;;oHX)l-.~1$i21 .-\::WC:+Oll .\071;;-.)1'

pri~a 'rina (fok. pod stanici~

odirect w.'<Ie(Iocus above slalion]

direcl wave[locus below slalion)

ohead Wilve

Fig. 1Output qf program

- 110 -

_ ...-_ ...- 'oIe:oif)~

\\I,,,,

II,

//

/I

I

II

I/

IIII

r--JIII,

II,

I,III,II, /~

t .> \\L_,

III)

I/

II___ J

'3

oO

OCO

"

oO

O~

iliC)O

g EI"

Fig. 2

x = underground station &= surrace station

xxxMap of seismic networks

zxSeismic Polygon Ostrava-Karviná Coal FieldLocal seismic network Lazy Colliery

111

7.'..2.91 15,.3\ ,77slt.! utlum,

E- 1I,~5~!~0. i tru aao . 630.n 65 th-O dli,130.0· 01.7) .700E-01 Frnf n .769E'OO

" o

A

tnod(> 1.2?~.2.91 15,31,27 E-

9tt.l utlum,-l1I,~55!50. !lO!3~O. 630.

n 65 th-Q dl!,-04.4'·~102.5) .146E'OO Fmln .142E'Ol

o

B

[lg. 3. OpLjmi~aLion crlLerlon effact...A standard ampJ iludes motlonB reglslered ~mpl iludes mat ion0- di r e c t. v a v e focus above slation)

Ď. - direcl wave0- tre e d wave

focus belo\.' sLaLlon)

- 112 -

II '~;~11 ~I' .!J

mr"I,..!. ?1'1. I .Ql \.n:??:...,::! F:-5."'~ 11:"':=;<)000

r:it.l \lt.l\1m:-l 0··60 t.h-O.11D?7.,:1.O. "':=;0.

nll,

26.5) -,298EIO() Fmjn .79J~fOO

o

A

[~~~~_-1~mod e I.?

1.1.QI lf1:27.:1? E"5.e5 11:155980. 1107.7J0. 150.sil.l u t Lurnr r-L 0-60 th-O dll,

OSRV(l:2) :('76./../.3.6) (?53.0. 17.3) (109.3. 36.7) -.310f,IOO Fm í n .69óF.IOO

o

B

Flq. 4. Influence of Input amplituda changes on a calculatlng focal

mechanlsm generatlon vtth registered amplltude mot ion for ar(

optlmlzation criLerlon.A - amplllude maLlon value ln PRS sLation -3.Bxl0-8 ms-lB - Amplltude motlon value ln PRS statlon 49.3xl0-8 ms-l

0- dlrectD. - dl r<ocl

wave (focus above slatlon)\J't".].ve (fo~us balow slatlon)

0- head vavo

113

~~.2.01 1~,.31,ns i t . 1 u li um :

II, 4~~1 ~o. 11'1D~0. 630.n 65 th-O dli,

I.l!lRV(1 : 2) , ( 12.5.00.6) ( 39.20177.7) 130.0. B1.7} .708E-01 F'min .769EIOO

o

.6.

,,'-;'~

- ---"" ...---- ~_.--" o - :: --'"-~ ---»>: -

:~~:~::;::::=::~.z:----l ..--~~- .,...-,-'" _/#

L ~~=.[-.:~~~=~:~-~ji ~'y,. ~Q'\_-'·9._.-~i/

h;-~1:<------7-;/- ,··:----;1~:::>//

7.1.2.91 15':''1,27sil.1 utlum:

E- 1I,1~5~50. 1101310. 630.n 65 t h-D dli,moo~I.2

PSIlV(!:2},(59.0.38.3} (301.7. Ol.l) (-66.2'-'123.9) -.2691; ..01 fmin .1J56EIOO

o

B

"J.-J~

........<--~"---:.,---""-.',-'---~:-......,., .>:

. '~,_i--. O \ Ir-N~>,,_ ~/)<J

tJ. ~- -- --6- --- /

~ ~~;~.~~;;--:~;:-:~~/ľ

Viq. 5. InClu~nce of X coordinaLe value changes on a calculaling [ocalmechanism qoneration.

0- d i r o c L v a v o focus above sLalion)1'':'' d í r o c t. v e.v o focus below slaLlonO· head v ev e

- 114

Seismic Polygon ostrava Karviná C0~1 Field cenlru.

2. SELECTION OF CRITERION OF OPTIHISATION

Minimum sum of of differences of lheorelical andstandardised measured value of ampliludes molion yas considered lo bea críterion of opLimioalion in Lhe oriqinaJ version af Lhe prograM.Srna11 values of a-mpl i Lu.de=s nod"J surfaces caUAé non-uniformveiqhlinq of informalion lhe sLalions. Therefore our updalerlv~rsion enahlR~ us lo use a crll-erion oplimisalion. the sum of squar0So ř reli'ltive deviatlons of measured and Lheoretical ampliludes mol ion( Ke Lé b o L al 1991 )

The calculat.ed value of t he volumelric component of lhe focalmechanism iG much greater in case of lhe crilerion af oplimisaLionselecLed. whlch correspand v í lh lhe Lheorelical presumplions for

yorks. The sensiltvily of lhe resull on lhechange of inpul values of ampliLudes .•..as supposed lo be higher. h01.leverthis presumplion .•..as nol confi~med (F!g. 4).

The resulls 3r'e differenl v h i I e using various opLimisalloncr'iteria. For rouline calculaLions ve provisionally used Lhe orlginalcriterian, buL for tesL seL of seismic reg!slralion of explosive vorksye are g01ng Lo use a nev melhod (Fig. 3).

3. INFLUENCE OF ACCURACY OF FOCUS COORDINATES

For an explosive vark and a minlng Lremor ve performed calculalionof [ocal mechanism generatíon at. chang"e of every coordinat.e ± 300m vit.h slep 50 m. We Lheorelically presumed Lhal Lhe result. 140n'l bechangeci al changing horlzonlal coordinaLes, or only i nsubsLanL! a 1 lywhllsl deplh cnordinale can have inÍluence on Lhe ray passing Lhroughanalhal" layer af surrounding and can influence lhe resull a greal deal.

The lest sho .•..ed LhaL lhe resulL cauld be effecLed alsa by lhe Íarmof minimising funclion. If more shallow minimum occurred. \le can gelanother resull even havlng inaccurale hari~ont.al coordinaLe.(Fig. 5).

ln case of deplh coordinale lhe lheorellcal presumplion wascanfirmed. There are Lhe deplh values in Lable I I, which set,quaJ iLalive changes af resulls.

- 115 -

Tab. I.(d -

Types of medium modelsdepth. Vp - speed of p-vaves)

,--I modelI

i [~J

1--1I 1470I 2627I 72581>"12581I I~_---.l

rr-=;de 1-:~~-n I I.2 model .sv mode I. v- rI Vp I d vp I d Vp d Vp[ml sl [mj Imis] [ml [m/sl I [11'I] [mIs)

I r t -- I - 1504215 I 500 3700 II -150 800 8005089 II 1500 3981 II 500 3200 I 100 3200

I 54731/

2500 47531 1300 I 4200 1300 42006478 6840 5780 1>1300 5500 11>1300 ~jII 30000 6150 I

II >30000 I 800011 I

Tab. II: Deep values vhich set qualiLative changes of rockbursLs[ocal mechani5m generation results influence medium model(eee fig. 6)

d_ depLh value lese Lhen original oned. depLh vaJue greaLer I.han oriqinal one

r model I-I d_[mJ d+[mJ II u:I 2 II 540 :DI kOS 495 760I sv II 460 910L___v __ ~_ll 560 no chang.:j

4. JNFLUENCE OF ACCURACY OF INPUT v~LUES OF AMPLITUDE

ttest..seLs.

The experiments viLh inpuL data of ampliLudes vere performed 0nChanged values on some sLaLions vere used for calculaLions.

evenLually an opposiLe mark in Lhe ampliLudes vilh Lhe highesL absoluLevalue vas used. There are examples in Lable III.

Whsn omilLed Lhe inpuL value fr-om one of Lhs sLaLions from Lhn.

complex of amplituda. Lhe resull vas differenL Lhe seismic medium modeldepend nn.The posiLion of lhe slation al50 influencss Lhe LrajecLory ofthe seismic ray and the resulting model of formalian mech3nism af focusas \.Je II .

4

Fig.

A

1

2

3

- 116 -

8

..

c

o

N-L.

:~-?Zijj~~)...-»-> --- - (-:. _.:;~O..::--::=:_#-----;- ..•.---:-- 0--:...--:~%@~~o --

-: --'. r)r> rv::;.:~_::. ../

--<~- _./. ,..6. Models of focal mechanism for four seismic medium models and

changed vertical coordinate of focus see tab. 2.1 - model 2 A res~lt with original depth focus2 model kOS B result with depth focus less then3 model sv original one4 model v C result with depth focus greater then

original one

- 117 -

Tab. III. Examples af lnpuL aMPlituda mation influence onresult of det.ermination mechanism foc1 generation.(The original values see ftg.I>

changed changad values D[oJ I SrO] R[ oJ V[%]channel of input ampl.

Ikvey,majy +2.2, +9.04 84.9 177.7 90.7 3.9

~e2

I 5.1 349.7 82.

1-1.65-

12.5 39.2 130.8 7.i 80.6 177.7 91.7 I!kveK,y'2 +2, -22.+16.5 56.5 286.7 -68.4 6.5I 39.2 71. -119.2

kve",.26", +0.02.10. 77.9 174.5 90.2 6.612.1 353.6 89.2

!mai""y,,,, 1+9.42,+9.04, -2.99 83.2 173.7 91. 6 5.3I 7. 340.7 77.1

IkVe,.. lut",. +0.02.+8.82, 76.2 345.7 -1.5 -8.31262.29", 1+10. , +8.1 I 88.6 76.0 -166.2

/kvex,v, +0.02,+2.2,+9.04 85.3 178.3 90.7 3.8!majy 4.8 349.4 81.1

IkVex,rajz 1+0.02. -21.2 46.1 14.7 -110.3 5.9I i 47.7 223.4 -69.8I !Ikvex.z 1+0.02,+16.5 78.8 167.8 83.0 8.9I I 13.2 19.9 121.5

kve,..Y,2 1+0.2. -22., +16:5 56.5 286.7 -68.4 0.7I 39.2 71.0 -119.1

kve><,v,z, 1-0.2, +2.2, -1.65 45.2 131.1 -41.4 4.6I I 62. 252.9 -127.1,Ikve><,v,z, -O .2, •.2. 2, -1 .65 66.5 183.8 -84.7 1.4ma)H,y,Z +9.42, +9.04, -2.89 24.1 350.6 -102. O

5. INFLUENCE OF SEISMIC MEDIUM MODEL

The seismic medium modele influence the result a great deal.(Fi g. 7) Accuracy of all ot.her input. values 1s delermined by t.heaccuracy af measuring and deducting and it can ba influenced by lheinLerpreLer Lhal works accuraLe ar ~akes mlsLakes lhal can be exaluded.From lhls paint of vlev lhe resull should ba unamblguous. The selsmlcmedium model is only very inaccurale approxlmallon af the faal and cancause a considerable 1'lisLaJ,:p in !,he ci'J.lculn.Lion.

- 118 -

o'i..~• • c

O· - o. ""'":J f. ~ .eo~ o o~ ox ~ ť; ~" '» •..• 110o CI o Itl:: ~ ::: ~~!ti o ~!;;I o_v ~..,.., ., n ."1ln oD ln ,...•• •• I

'" IC •~ ; Z ~;, Z

c r- -I •

,w N '" NN ~

j g •• ~ ~ I ••~~ ,. ~~ (!').. n N

n •... I " ~

" " -o _ ~

~ ~000... 0-_ N

MJ O N&l ..,

••• •• ••• \li,... ~ t'<I 'O

liJ" N e ~ ;:;J <)O ••

n JI( •..•• n ~•• • - J:: • -i;~ &;~~Io .,~B

OO OO •. •.w ~: N•..

• • C

O' !: ~. l~ f 'ij~~ O ~ ~ ~

~ ~ (; ř:•...• ID •..• .,

~ f! ..... .~o • ~I ;;I O~!;:: O _ •.•~ •. ~ ~ T.., •. ..• '" .;: • n ~ I Z

:J ~ Z : ~c ~ !.

• ..... 11 '1.., •.. ...•. I:: 9 ~ I ••g - ..• ;.

~~: ., ~~ ln

M •••• N•... - .." •.O •.._ ~~- e Ň~ :

~~ ~; O-

~ •• N '" : I

ill- <)

~ o n ~ ~n N ..., r-. . __illn q!F'I'1. 7. F'o c a l mechanlsms \liLh four selsmlc medium models'.

O. cl.lrecl. "C\ve (rec-us abeve sLaLlon)

l!. - dlrecL vavs (focus be Lov el.a t.Lon

0- hP.'ari v a v o

- 119 -

We appJy the Slx-layer medium model (model. K05) (see tab. I), forrouLlne elaboraLion of seismlc daLa, which Is applled also ln theSeismlc Polygon OsLrava-Karvlná Caal Field actually. BoLh model.kOS andModel.2 was calculaLed in Selsmic Polygon Ost~ava-Ka~vtná Coal Fieldfrom lhe hodochrons. 80th model .sv and model.v vas judged frorn thearrival Lime difference belveen underground and surfaceslaLlons. Gradlenl of veloclly has been supposed.

seismlc

6. CONCLUSION

While calculating the rockbursls focal mechanisms by inversíonmelhod of ampllludes it is necessary to take lnlo conslderalion lher'()ssibilily of random fO~li'Iation of differenl resulls al lhe sameseismlc event wilh changed inpul dala.

Il Is necessary lo know horizonLal coordlnates with accuracy~200 m; accuracy af deLerminaLlon focus depLh depends on selecLedmedium model (Lab. III

The Influence of inpuL ampllLudes moLlon values on resulLlng [ocalmechanlsm generaLion Is noL Lao meaningfuJ. Alloved misLake of inpuLvalue of amplituda molion Is one order (tab. III) .

Il Is necessary lo pay special atLenlion Lo maklng of lhe seJsmicmedium Model because iL prlncipally influences the resulls.

ImplemenlaLion of oLher oplimislng crilerid LhaL use relaLivedevialion of measured and theorelical ampliludes' moLion Is not qUiLeevidenl.

REFERENCES

SIIený. J. (1987). Mechanism De~erminaljon af Mlning Tremar Foci bySeismic Waves Ampliludes Inversion. Report of Geophys1cal InsliLuLe ofCSAS, Prague, Czechaslovakia. (In Czech)

KaJáh, z. ( 1991 ) Mo.chanism of Nining Tremors in Karviná Part afOstrava Karviná Coal Field. Phd Thesis, Ost..rava., Czechoslovakia.(In C:zech)

K""J áb, Z.,

DeterminalionSLaš, L. and

Mer;l1anisms afVesel'A, V. (1990. FirsL Resulls from

Mining Tremors ln Ostrava - Karviná CoalIns\... Geoph. Geo!. Acad. Se. M-16 (245).Fleld. C29choslovakla,

(In r'rinl)Puhl

Kaláb,Z eL al. (19911 .CoMplex EvaluaLlon of Heasuring Syslem RDP wlLhPolnt af Vlsw Fulfilemenl Requiremenls af Baslc Research. Final Report.oí E05 "Complex EvaluaLion nf iieasuring SysLem RiJP vit.h Po í n L of Vie •...

- 120 -

FulFilemenL RequlremRnLs oC Dasic Research", Minlng InsLiLuLe af CSAS,

OsLrava, Czechoslovakla, (In Czechl

KnoLek, S, sL al. (!991). InlerprsLaLlon DC Seismlc EvenLs in RDP.Research Report for Part of Research - developemenl af technologieprojecL TP P 01-826/90, OKD OsLrava, Czechoslovakía. (In Czech)