1.

$.JAT~· ·OF cJlliPORNIA;--TH'E. ·.RESOURCE:$ AGt;N(:\i

DEPARTMENT OF CONSERVATION

DIVISION OF MINES AND GEOLOGY DIVISION HEADQUARTERS RESOURCES BUILDING, ROOM ·1341 1416 NINTH STREET SACRAMENTO, CA 95814

Olfutc:t. bfftc:M:' , LOS ANt;;i;t~$ SACR~MENTO Junl~f~ S.rri:i 'Ilda., Rm •. 1060 107· Scuth Bro'ac!Wav

Rlli.i;Ource1 B1d!lil··· R·m. 118 1416 Nlnth.Streiet

S 'N PRANCIS(:O F rrv Bulldln.sl. 9 TH

:90012 9581-'

,,.... o. hrk.land County of Sat• Clar•

Jiii• 20, t!lt7

Coullty lkmll'IWMt hnter, E••t Wh111 70 V.tt ll9ddf111 lt..-t lean J.,... C.llfomla 9Sfto,

fleer Jhn

Thl1 It to ackncwled,.e reeatJt f the 1J rewrt1 1vlmltt•!I with Y'l'•" l•t.-r of June H, lt77. ••ven ,.,.rts hhlfltlfled ••.•roved by you .. 11 tying whldn ,,..,,, ~tudin :lorte.I wit I be plaead on open fl le at ~·''*' ·-l.r;:;· rh for 11 ... Jil.lto, Spen•r• lftl.d•• Marrl1, · tran-sian 0 Imm)• · · . other reports wl 11 be placiuf Jn our I nf«tml fl 1111. · , · , ·. . · .

'

wdi 'Wl V f HAlll . . Offl.C!.Jof_the ltat• Geolotl•t •••• 1'12 ...

'

MtlWlt

UI · A"P fHe V

-. ::..... ,:': .. '. -:

. Engineering Geology Unit County of Santa Clara Land Development Engineering 70 West Heddlog Street San Jose, CA 9511• (299-2871)

./. 6~

·, ... ,. ~.~, '.>~:~.;~~- .~' ' "'(\ , ..... ,_,

' ' ~ ~ .. ~:-·{· "

Oellfornia June 15 1 1977

State Geologist C/O Earl Hart Californit1.Division of Mine and c;eol gy Ferry Building San Francisco; Cal:i.fornia 94111

Dear Mr, Hart:

Attached are 13 qopies James Berkland, Santa Clara of the Alquist.w.Pfiolo Act •.

. . '

, ,·'

of g.ei:>lo iel'li reports sul::inlittea):6 , County G ole>qi•t; under tb,e provisions The rep<> ts iU:-e .as listed" below,: .

. . RllPo'RT REPORT # STREET OWNER F.ILE NO. Ql:OLOGIST ' PATE

APPROVAi>· DATE

Archibald Lane Harold Martin

2 .• * Bayview Drive Den Boer

3.# Clayton Road J.ohn Sies

Deerpark Road Larry Morr:l.a

F.leming Avenue Melo

Hiquera Road Spencer

7. * · .. Ir111a Lyle Drive Gl.en Morley

4574.2 Parcel l 77Ml2.l0

J.C. 'P.renderga11t, 12/02/77 01/10/77 (CEd 955) ·· ..

9 J •. c. Prendergast . -92/16/77 03/28/77 . (CEG 955) ·

77M18.1134 Edward Danehy . 06/07/77 06/0S/77 . 75ltl8.S7 (CEG 8).

76.GCll. 226 Joseph Gal:>riel l'/./07/76 12/22/76. 76Rll.657' (cEG 256) 77817. 3665 R. Bu.rt.on ROae. '0Sf04/77 05/25/77

(CEG 160) ' R.ol:)$rt L.. R.ose ·76Gl8, 2 ·

7GM12•l (RG ·'20 2-5) . .

"'·12/o6/J6

ti0/22/76

01/18/77'

11/22/76 Edyard. J:)anehy. (CEG 8 )

8,# Morrill Road cb.r.j.a Zynda . · .. 12.S?l,l Frarle:ia Stejfl!r , 0~;(04/77 OS/Z5/77

· ... ·.1· .. · •. ·2···S·· ·P.· .. • .. ' .. ·.· .. 7· .f··· ... ·· 2. ·.·. ( cEG 2,9 l ' ila·d .... ei'Jdtlln r. •. c+d 5/25/77·· .. Mo:trill Road Ron'· Hariis 77Bl2. 3 31 rrancis stejer ' /o(\4,(14/'1'7 05/09/77 . . ' (CEG 269) .·.

Branagah · 7§&12.~ · J~remy. Wire 12!02/76 .12/07/76 · ·. .· ~ (CEG .'11)

OS/29/76 06/16/76 ~1:# Ol"- silnta Cruz H'Wy ... Jack Brown 76B1.2 .• ~.·· 43 R. :eur~.· R!)se .(CE.G>iEiO)

16···M ... 1.1.1~·.··.' 0. R .. :· a.<· ~~r~~ris .. e · 11112116 12102116 7786.36 3 Edward Danehy .. OSJ09/77 05/23/77

12·•'1< .Shlilnnon Road George SIJ!t~

13.* Upland Way Lavan Boc'k · · · . ( CEG 8 ) · ···· \.. :.: ~ ~. " . ._ ....... , '. .

* ... Tll.ese reports concern areas not''~!:(Alquist"'Prtolo Zones but in Count¥-d~sigrtated Hazard; Zone, and ~re 'included for, yo1U"

• ;;;· ~~ .. ~:'"~!~:!¥.:~i~r~~9r~:~~.:.,i•w -;~ , . ,,_ . . ~ I~ "

.H An &qua: Oppo: ~nlty ~mployar :;

• ~:d.sz • Sincerely,

s9.:-·w11~ JIM BERKLAND

. ... , ' ', , ..

R. Bu.Ion R ..... M.A. (:ii c':1Lt)ro1~'T

F.NGll'.flE"ERING GEOl...OGIS"f

!C' ... L.ti<"ORNIA PllCGlaTRATIQN)

~;n'ITE \c,EoJ..O(f; 1.:;,T s Ce>PY

,&LJ,,rf j;V & /ti/&,

7?-B 17-, 3G&<5-

/J P-467

ALLIED GEOPHYSICS ~'A s-11- rr '?.'1 Engineering Geology Unit County of Santa Clara

P.O. Box 583 ~AN JOB~, CA, 9!il06

Melo Single Residence Site

APN 612-2)-44

Land Development Engineering 70 West Hedding Street San Jose, CA 95110 (299-2871)

North side Fleming Avenue

Santa Clara County CA

S.E. corner T.6 S., R,1 E,, MDBM

In-depth Geologic/Seismic Report

File

Melo Single flesidenc:e Site

x Al'N 612-2J-44

North side Fleming Avenue Santa Clara County CA

S.E. corner T.6 S., fl.1 E., MDBM

Scale 1 in. "' 500 ft.

Area Aertal View

(from Santa Clara Co. orthophoto 52, 19'/0)

ENC..l"IEEF11Ni:;. Gl!'.OLOGIST

(C:AI .. ll'"O~NIA "'!'.r'.\l~"l"RATION)

i\11 ltD Gl.OPllYSIC.5

P, C.'>. Bcix 58:4

SAl"-I ..IOt.Y.°, CA, 9~1[...I~ (40Bl 2.59-2698

May 4, 1977

Mr. Steven A. Arnold 1211 Park Avenue Suite 201 San Jose CA 95126

Dear Mr. Arnold:

Re: Melo Single Residence Site APN 612-23-44

North side Fleming Avenue Santa Clara County CA

In-depth Geolog1c/Se1smic Report

Thank you. for this opportunity to study this proposed homesite placement and construction.

The recorded land parcel is in the Alquist-Priolo Zones of Special Studies 1974. In addition, Santa Clara County ordinances and regukations apply.

The study and report are favorable in conclusion with a list of mitigating requirements. These are based on the geologic and seismic conditions prevailing at the site. They include wood framed construction, an acceleration design factor of 0.15 g, consideration of pier foundations, latest UBC specifications, minimal necessary grading cuts, and control of water runoff onto site and from gutters.

All utility services are available, an important item. If you have any further questions, please call me at your convenience.

Respectfully submitted,

~~-*-~~ 5 copies R. Burton Rose, M.A.

· •.

. - ··----,.·-· -.

'

Approximate scale. 1 11 = 500 1

APN 612-23-44 /)

Vicinity Index and Alqulst-Priolo Act

Special Studies Zoning: 1974

Composite:

Scale In. 2000 ft.

San Jose East quadrangle Calaveras Reservoir lt

R. Burfon Rn>o, l'-·A.i\. ENOFNEE1'riNG Gj!.OLOGIBT

ICALr..-clltNIA Rit.IJIJ!ITR:ATION)

ALUl:D GEOPHYSICS

p,o. eox ~a=~ ~A~ Jt;l~E. CA, 9i;1(.J~

In-depth Geologic/Seismic Report

APN 612-2)-44 North side Fleming Avenue Santa Clara County CA

Melo Single Residence Homesite

Date: May 4, 1977

Introduction: This report summarizes a geologic and

seismic study of the site addressed to the Alquist-Priolo

Special Studies Zones Act of 1974 and County of Santa Clara

requirements. The study considers planned construction of

of a single lot home. Proposed construction is considered

suitable for a wood framed house on a foundation designed

With considered attention to expected regional earthquake

shaking. The courtesy plot plan provided was reduced for

an index to the placement of one seismic refraction survey

line. Public utilities are available. One day of field time

was included in several vicinity visits.

Location: This single building lot is on the north side

or Fleming Avenue, east of Alum Rock Avenue on the east

edge of the Santa Clara valley, with the specific site

'

612-23-44 2.

added to the accompanying geologic, topograph and property

maps included in this report. The recorded parcel is in

the south eastern oorner of Township 6 South, Range 1 East,

MDBM, in the mapped Pueblo Lands of San Jose, but in Santa

Clara County. This parcel lies just below the limits of

the north line of the San Jose East 7!0 quadrangle; hence

this topographic map and the Calaveras Reservoir quadrangle

to the north are combined to make up the index topographic

and Alquist-Priolo Zones vicinity plate.

~: ·Basic and essential geologic, structural, faulting,

seismic, and topographic factors are considered and shown

on the map plates following this written summary, followed

by a pertinent reference list of published mapping and with

Several more general seismicity data pages. One sub surface

seismic refraction survey line was run to determine velocities

of the parce1 ground at this sloping site. All of these

factors are evaluated in context with each other in the

conclusion and associated recommendations.

Vicinity and Site Geology: This proposed house site lies at

the western edge of a small area eroded knoll, subjecting it

to limited rainfall runoff which can be guided around the

shallow cttt house pad on the plot plan. This knoll to the

north is mainly older alluvium (Qoa) to depths of several

tens of feet. Recent allttvium thins at the valley edge (Qal)

approximately at Fleming Avenue. The older eroded alluvium

612-23-44 3.

oTerliee weathered bedrock of Cretaoeous age ae mapped by

Dibblee (1972); inoluding the Oakland Conglomerate (Kego)

coarse sand., cobble and rounded boulder formation, and to

the north west the Berryessa sandstone and ehale (Kee & Kah)

formation of eimilar age (Crittenden, 1951). Thie bedrock

seriee dips eastward with a NNW-SSE strike terminating at

the mapped Quimby fault on the north side of the knoll. A

splinter of this fault may lle in trace position north of

the north line of this site as evidenced by an outorop of

Cretaceous age silio&-oarbonate rook (so), an alteration

prod•ot of eerpentine, a basic mafio intrusiTe. This small

outcrop and one more easterly indicate the probable trace.

Rook fragments were found in the surface organic soil mantle.

Another fault trace is mapped south of Fleming Avenue with

a more northerly strike, a thousand feet from this site.

None of the field work, or published mapping indicates any

fault trace across the specific parcel considered in this

report. The Quimby fault is the western edge of the active

Hayward fault zone in this area as mapped by Dibblee (1972).

The second active fault system on the easterly side Of the

valley is the Calaveras rift zone approximately two mlles

to the east. Both strike NW·SE in multiple branching fingers.

They have experienced historic earthquakes exceeding 7 in

magnitude, The major active earthquake rift zone is the

San Andrea& fault fifteen to twenty miles to the south west

through the Santa Cruz mountains. The 1906 •san Francisco•

·,

earthquake had a magnituda of s.2; (Greensfelder, 1974).

Future severe .earthquake shaking must be expected from all

three sometime and will affect the entire region. The

shallow surface soil is similar to Altamont clay loam

(AcE2) having a moderate expansive characteristic.

Landslide Potential: Landsliding movement within and upslope

of this parcel is considered or low probability due to the

short distance to the top of the knoll limiting runoff from

winter storms. However, such runoff should be guided from

crossing the proposed out pad and house drain gutters should

be controlled past the lower limits of the pad. Grading

slopes appear atable in a completed pad out next door to the

east, although more shallow cuts are preferable.

Seismic Ha:tards: Previously discussed future severe earth­

quake shaking is a pervasive regional expectation. The deep

alluvial fill Of the valley will probably react with more

intensity than the low foothill zones where higher velocity

bedrock ooours closer to the surface and erosion slopes are

not as steep as found at higher mountain elevations. Ratios

of magnitude and intensity are approximate and are included

in the append.ix. Because or the site surface slope combined

with the potential severe earthquake shaking to be expected

through out the region, a minimum design acceleration factor

of 0.1; g is warranted from a geologic and seismic aspect.

The latest UBC code should be followed if higher. Piers for

·.

foundation support and ground ooupling are suggested, but

should be a deeign ohoioe oorrelating with the house plans.

Seiemic Retraction Survey Data: One reversed recorded line

170 feet in length was run run the length of the parcel and

extended acro&a Fleming Avenue when reoord.ing from •s•. The

1tation to recorder summed travel times and calculated sub

surface velocities are contained in the Time-Distance graph.

Time was measured in milliseconds and the resultant velocities

lhown in feet per second. A Bison signal enhancement summing

811smograph was used in the field eur'fey. Depths below the

lttrraoe were computed for increased velocity horizons and are

the basis for the geoseism1o profile seot1on which also has

geologic and 1truoture input in interpretation. Three ranges

in velocity were found:

Velocity Horizon Depth

v1 830 ft. sec. Organic soil mantle 3 rt.

v2 1540-2000 • • Older alluvium Ill weathered or Qal

v3 2670-)080 • • 8 1-10 1 Older alluTium unweathered

The weathered or normal horizon surface or the Oakland

Conglomerate was not reached with the recording survey line

length limitation. This vertical depth of below 5000 rt.

second alluTial material again suggests pier foundations for

increased ground. coupling of the planned construct.ion. No

abrupt near 'fertical low Yelooity zone• were indicated, nor

different horizon layer patterns at the two end stations.

·,

612-2)-44 6.

Seismio interpretation is in context with the geology.

Conclusion: The combined and correlated data inoluded in

this report are favorable to the proposed home construction

with some mitigating requisite reco1111Dendations as listed,

inoluding wood framed house structure and the latest UBC

specifications, together with an acceleration design faotor

of at least 0.15 g to assure severe earthquake shaking as a

design oomponent.

Heoommendations: These requirements are in addition to those

inolud.ed as part of the favorable geologic and seismic report

oonclusion:

1.) Minimal neoessary grading, foundation not on fill.

2.) Control of hillside and roof gutter water runoff.

).) Latest UBC code and local ordinance regulations apply.

4,) Engineered foundation pier design be considered.

5,) (from oonclusion) a.) wood framed house construction.

b.) design acoeleration factor of at

least 0.15 g be included.

Respectfully submitted:

5 copiee

Melo Single Residence Site

)( APN 612-23-44

North side Fleming Avenue Santa Clara County CA

S.E. corner T.6 S., R.1 E., MDBM

Approximate scale 1• = 500 1

Parcel Index Outline Map

(from Santa Clara Co. cad.astral survey Plate 52 - Jan. 1974)

V//~~

/.'16: . /

. / ',J

0 •.·;,:,,

!! ·~ ' .. · .. '.·· ··.· ~ :' ' ~

., .. '

Melo Single Residence Site

lf/1' APN 612-2)-44

North side Fleming Avenue Santa Clara county CA

s.E. corner T.6 s., R.1 E., MDBM

., ..... ~,-~~-· ·····--- .... ~·-------.'.! ..

Contour interval = 20 & 40 ft. soale 1• = 500 1

Vicinity Topography

(from u.s.G.S. 7!0 quadrangle maps: San Jose East and Calaveras Reservoir, excerpts enlarged)

I'•'• ' '

'·. '·.· .. ,,·· .. ,.~. j ,I "

~ .. '" ' ;,, ,,. ' '~

·-··--• ...

Melo Single Residence Site

APN 612-23-44

North side Fleming Avenue Santa Clara County CA

S.E. corner T.6 S., R.1 E., MDBM

··--··...._,,.,., .. ____ ,._

Base map contours : 20 ft. Soale 1 in. = 500 ft.

Bedrock Geology and Faults

(Compiled from field examination, Dibblee-1972, seismic refraction survey line, referenoe searoh of vicinity area, se1smio1ty data)

AcE2

ere

Soils Lee;end

Altamont clay series: (15 50 JO% slopes) eroded, average slope 20% with house site on near flat knoll, moderate sheet erosion, moderate erosion hazard d·ue to minimal up slope runoff area, well drained, moderate expansive tendency

eronley clay series: (2 to 10% slope) gentle to moderate slope alluvual fan, medium to slow runoff, some silty clay loam, slightly expansive, erosion hazard moderate

Geologic Legend

Qal Recent alluvium and stream bed material

Qoa Older alluvium, partly eroded

Tm Tertiary (mid-Miocene) Monterey shale fm.,

Kss Kah

siliceous, extends SW as bedrock to the concealed Quimby fault

Cretaceous age Berryessa fm., sandstone, siltstone, shale intermixed in deposition

Kego Cretaceous age Oakland fm., coarse sands and cobbles

sc silica carbonate: altered intrusive !llass of serpentine, Cretaceous age inferred

<!J o o concealed fault

- - format ion contact

-.......__ ·strike and dip

•'

Ill iJ

5 :.J .. ;:)

J J

~

10

9

a

4

3

2

0

-·--I

=

.-__

::

BISON ALLlELJ GEOPHYSICS F. o. Box 5BJ San Jose CA 95106

·'---· '.

- : . - < ·-

..

. . . -- -· -- ~

..

~··

--~ -+--

--OPERATOR

TRAVERSE

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- :"-.__.E-- =!=~·=---=-- '

.+--

• - /- /Z'1' /.Ji1C -,IP. IU-#'_7"-'A/R_,s,.- C" P..?.P7

A-, /.$,,,of ..,c ,,.,- r.

I.. 0 C: AT I D N f DE SC RIP TI D N _....V._'..F __ s_;;.:/....;:.P."-"'~;.__-'.:;_.:;L:...::E;...:;.""..;...;-';...;.h'<.;..;:~;.,_A:;,;:..;_Y...::";#;;.:.·_,;.T..:. ?;:..:/P:..:...:.·..:C::.:'/::..:.A;.;R;.:...;.:'11':..=c"' .

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-l.'!l,,~_,~~~ ., ..... """""'~~ .... _

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A¥V. riw' ... oo11 J

&rtM,_ P~n rar ,, &.:t,,,r~~ ,,, ..;. .... Tw. ~h AP/II (.l~·i'J·H

·-- --·--------· Approximate scale 1"=40 1

Seismic Refraction Survey Line

.,,,.J>r .-o -· - ---/--

r'

·.

Bl bl iography

Sol ls of Santa Clara County: U.S. Dept. of Agriculture, Soll Conservation Service (1968), with aerial soil map @ 1" = 1000 1

, Santa Clara C~. CA

Geology of the San Jose-Mount Haml I ton area CA: Crittenden, Max D., Jr., State of California, Dept. of Natural Resources, Efol letln 157 (1951) p. 57 & maps

Geologic Guidebook of the San Francisco Bay Counties: California Division of Mines, Bulletin 154 (1951)

Geology of Northern California: CDMG., Bulletin 190 (1966)

Proceed1ngs of Conference on Geologic Problems of the San Andreas Fault System: Stanford University sessions, Publ./Geoloqical Sciences, vol. XI (1968, Vol. XIII (1973)

Urban Geology - master plan for California: Bulletin 198, GDMG.: p. 20 (1973)

Prellmlnary Photolnterpretatfon and Damage Waps Landsl~de and other Surffclal Deposits In Northeastern San Jose, Santa Clara Co., CA: u.s.G.S. map MF-361 (1972)

Preliminary Report 18: CDl/G (1973)

Earthquake Engineering - a symposia: Wiegel, Robert L., coordinating editor, Prentice-Hali, Inc., N.Y. (1970)

Handbook of Engineering Selsmology: Mooney, Dr. H. w., Bl son Instrument Co. ( 1973)

Maps:

u.s.G.S. topographic quadrangle 1:24000, 1" = 2000' **· Geologic map of Santa Clara County: 1:62500, Santa Clara

Co. ( 1974)

Geol~gfc Wap of Callfornla - San Jose sheet: 1:258000, COMG (1966)

Prellmlnary Fault and Geologic Map: 1:750000, CD~:.::; (1973)

* Calavera~ Reservoir quadrangle (1968 photorevlsion) San Jose East 11 n "

Geologic maps of the Calaveras Reservoir and San Jose East quadrangles: DI bbl ee, T • .v., u.S.G.;;. (open t I I e 197 3) I : 24, 000

pf1;$UMED i':PlCENTER OF.__.,.. .. JUNE1'1BJ0 .EARIHQU~ NAC;NITUDE 7.0±Q.S

-.J,.;-t(.; P+'i PRESUKE':tl EPICEN'l'C;ft OF OC'l'OBER ll, 1868 1 EA.MHQUi\JO"; Ml.GNITUDE ?.oto.s

P~~UMED E'.PlC.!-;NTER Ot OCTOBf:R. 8, 1865 t ~ARTIIQUJ.X:E MAGNIT~OE &.S•0.5

( .... ~ .P+"'t

PP:E:SUMl::U EPICENT~:R or ,nJt.Y 1, 1911 t:1lRTHQUAXE •.'.

N "1-t C. l;i.)-J. >y.I •,' p -tS. I.: I

o~o '\~ PRESUM1i0 EPICI-;N'tER OF' ~(5.I)

2 OCT. 22 1 l');!C. EA.R"I'HQUAKE • o o

fM-tl /'j_J,lj 11..j 0 t p tJ \:: ~ 0 •

PALO COLORADO - SAN GREGORIO ,,, ..... 0

FAULT • •

EXP1,.ANATION

0 M"-'Jflit1,1da 4..0 - 4.9 ~ Ma9~itude 5.0 - s.9 • t!~ib..td~ 6.0 - 6.9 • Maqnit~~~ 7.0 - 7.9 • »agnltu<Je ~ a.a

(6.2} Ma<:jlnit~iW Qt selected •~•th.quakes

~ N

~ 0 e 16

rigi.ir~~ b~side th~ lQc4~1un~ indicate th~ 11\irrb~r of (';:ii;thquakes at the ~llffil!! place, all ~qual to o• alJl.lliller than tho Qnm pli:it.t.tid. SCALE IN MllES

~

l--/ ' \

\ ' •I'

FAULT JOAQUIN

FAULT " ,I

,,r ' _,_....,............,

/'" /STANISLAUS

0 / (

A' FAULT

'<

, I

I >

\

Ml E R C E o_ .....- _ I ,/ FAULT- --y---'<---~ ,

/

/ 0

' 0 BENITO,, ''-o

"-0 0

"

\

> \ ,, .....

0

•SAN ANDREAS FAULT

_..) ~

\-~ ~ ' ' ' ~ .J" "" ' /

0

' RINCONAOA ::w''S.. _t., \ ____ ~AULT "~-- \ =-"-'--·-: '

Figure 12. Major faults and earthquakes In the gre~ter s~n Francisco Bay area (modified after Rogers and Williams, 1974).

33

APPEND IX B

General Comparison of Scales Used to Rate Earthquakes at the Earthquake Epicenter*

Intefl!!lity

H.agnit~i:!:

JUi;hter Si;;a.le ""°0\fied t4o~C&lli ,scale

l<os!iii-Ft)re~ Muivalr.nt

I l

'·' u ·x-1:1:

III '" ••• IV rv-v

.. V-vt

\It Vl-VII

s.s \III VII!

• VIIl VIII-IX

11

"

s.o

•••

Not felt ~:.:eept Py fr;w undc:r: !avor~h cl r~ t.anc;:.e.t

Fl!llt Oy fetW i.t. :nst

Felt n.ot.iccably 1.ridoon

Felt ~ne:ra.lly

Felt ~r all. ~Y frl¢til!tll4114

e~tyoni!: rU."'.18 PUt­

tloor~, fel~ t~ IPO'lin.9 t;:&r!I

•...to

Olil'IP~Y!I • plut.er O~qed

Ve?')" destrui::tlv-e ~nd 9ener~l la.mage to ~el'Jt stl"\l~t\!res. Little Qa.m4ge to weil-b\tl.lt stn:ictures

Tot41 ~c~truction weak 5t.:t"1JCtT,Ireg. ;;i;;in.sider®l~

daJ.1a.ge 1./'ell-built. stru~turu

l"l<"-'!'DnlJI' and .f:rallle s t:ruc:-t.u:r~s cxr.n11::inly dcst~oyed. only be.lilt bUilding~ surviv•

Delic:a.tely li'D-~&14 obj~cts ~in.g:

CaL'!I roc-..Ji;ed, windain ta.ttl111d.

Oi:!lheg, ..,.L"ld0o1~ bro);el'

~nd11lurn cloi;k:s a~

fu.rr.it~ni lrlO~d,

i=t>ject..d upset

~nune-:it."I, wa.11.s Qq,.;n, f1u:nit\lre eiv~r­t;.u.tned. Sand ~d m\ld ojeeted. ctia.nq1:1"f in well......,a.ter l•Vl!;t.

Fol'\nd4tion~ d~~4,

ur..d~~·9rQ1,l.fld pi~ Qroken

Gr~u..~d b~dly cradeitd, i=a.ils b~nt. 'ltloei.~.r

al¢pf-ed uver ban);.9

BI"Q,,d lllisl.lrea. fault. llil c:a.rps. Under-9I"O~d

pipes. ollt of ••:tv.lm

Acceier~tion ~~I;'!!!~

<;ravity. wo11-ve~ 5~@D

in ~roW'!d. Li~• of !;ight and level. dist~rt~d. i;i;ije~

th:rQW:O i.n •.l..r ·

NOTE1 .Magn.i.tud<!. an4 ll'lt!!!nsity ot 4t!. e&et.hqu.!:k~ ~ ~t:irell' different. ~asuxl!l!W!n.t!J of •arthqu;,Ji;:• enUVY or efteet.a, ol-lld ean mlY b~ ~ai:t!d illt. th!!; ~arthqi,;1.M.a t!pic;:~~r.

1"111anitu<l.€' - 1• a t'lun:*:i~r d.t!:-1.v~d from iMtr~ntal. ~&.Sure1I1C.nU, ill.nd ~~ the: ~u-a.re of th• t!ne:&:gy .releMM 21y the earth!J',!ake. "J'"r.ut!; is ~ M..a¢t;l,,l.Q,t ~&l.Cl.114-Ud foe i:ta~ e&rthqi.tak!!I.

Jntr~ltv - i!ll a loc'lll rat.ing Qf eut.~q"-lalt;~ effl;'~ al.,servi;td and r~p0r-te<1. by p~opl~ ett tll'i'"f qiven loc;:i.tlon.. iti"'te~ r11t.t.int;is feit: one ~a.rtli.,;u~;9 v.t..ty e~ideraPly dl!perrd..ing M d.ii;~anCt! f:z:(;IJJ: epicentit'J", the n.t.t.UHI of. th~ &oi.l. Md roi=JI; be!\e&~· the ob••~r, &r"1 th~ r:.Qaei:-ver' a !.n~eyr~ut.i~n. of ·~~~ seen Q~ felt..

Calif. Div. Mines & Geology Preliminary Report 18, 1973

36

•

BISON SIGNAL ENHANCEMENT SEISMOGRAPH MODEL 1550

Model 1550 is a r1igged, light-weight statc-of..:the-art signal enhancement engineering seismograph designed for rapid and effective subsurfnce explora­tion. Its most important upplications are in determining depth to bedrock or other subsurface boundaries, and for engi­neering classification of materials at depth, The field work is carried out curn­pletely nt the surface. If used as a supple­ment to an exploratory drilling program, costs can be greatly reduced while ex­panding the information obtained.

The 1550 is a sophisticated multi­function instrurnent with many of the sarne features as the larger, more expen­sive Bison seismographs. This includes the capability tor signal enhancernent. introduced by Bison lnstrurnents which permits its tise almost anywhere - even in congested traffic and construction areas.

Its compact size and light weight. to­gr.ther witt1 its brilliant display and func­tional controls, make it useful to civil engineers, geologists, ·contractors, well dri!lers. and geophysicists engaged in;

Highway construction Damsite investigations Bidding and estimating Groundwater studies Gravel and quarry prospecting Foundation studies Geological and mining surveys

Explanation of signal enhancement

Signal onhancernent is a powerful signal processing tecl1nique which rimplifics the true seismic signal and reduces the noise interlerence produced by wind, traffic, and machinery. It accomplishes this by oh~ctronlcally summing and storing the seisrnic waveforms produced by two or rnore hammer impacts at the sarne location. The noiso signals arrive at random times so they tend to cancel in summation. The true seismic sigr1als are perfectly repetitive in arrival time and waveform so they are amplified and enhanced by summation.

The effect of siqnal enhancetnent is to: • Increase the depth of investigation by

a factor of three or more, compared to a seismograph without signal onhancem(}nt.

• Permit operation under adverse conditions of wind, machinery, or tralfic.

• lrnprove ease and accuracy of reading.

• Reduce field tirne by reducing the number of in1pacts necessary to get a reliable reading.

Wavqform without enhani;;11m1Jr'll. 1fllf!5f!ismic s1grials are difficult to distir1Quist·1 from noise.

Compotlle (tumm•d) w•~•rorm g•noratoel by three •ueee-•tlY• 1mp11et •lg~•lt. Seisrn le. signals are amplifieel ano clearly Qi~ti11guisnao10.