Structural damage by tsunamis

C H A P T E R 4

SOBUCTURAL DAMAGE BY TSUNAMIS

Q r v l U e T. Magoon

Navigation and Shoreline Planning S e c t i o n Engineering D i v i s i o n

U. S. Army Engineer D i s t r i c t , San F r a n c i s c o

100 M c A l l i s t e r S t r e e t San E r a n c i s c o , C a l i f o r n i a

T h i s paper presents a h r i e f d i s c u s s i o n o f s t r u c t u r a l damage by

tsunamis based p r i m a r i l y on damage produced by r e c e n t tsunamis along

the northern C a l i f o r n i a coast. Of these r e c e n t tsunamis, by f a r the

most damaging was the one o f March 196*; which caused approximately

$11,000,000 damage a t Crescent C i t y , about $300,000 damage a t other c o a s t a l l o c a t i o n s , and about $200,000 damage i n San E r a n c i s c o Bay. At Crescent C i t y , where the maximum runup reached about 21 f e e t above mean lower low water, damage was l a r g e l y t o wood frame s t r u c t u r e s o f r e l a t i v e l y

l i g h t c o n s t r u c t i o n and t o f l o a t i n g v e s s e l s . At other l o c a t i o n s , damage

was p r i m a r i l y t o commercial f i s h i n g and p l e a s u r e v e s s e l s and a s s o c i a t e d

shoreside s t r u c t u r e s .

Adinowledgement i s g r a t e f u l l y made t o t h e Corps of Engineers f o r

a c c e s s and permission to use data on f i l e i n the San E r a n c i s c o D i s t r i c t , U.S.

Army Corps o f Engineers and the many other agencies and I n d i v i d u a l s t h a t

gave t h e i r observations, records or photography f o r the w r i t e r .

36 C O A S T A L E N G I N E E R I N G

INTRODUCTION

E x t e n s i v e s e c t i o n s o f the coasts t h a t border the P a c i f i c Ocean are

now populated and undergoing continuing development. Many of these

developments are taking p l a c e I n areas p o s s i b l y subjected to tsunamis.

The design o f s t r u c t u r e s i n these c o a s t a l areas must consider the e f f e c t s

of tsunamis j u s t as the e f f e c t s of seismic or wind loadings must be

considered. Although the a p p l i c a t i o n o f the methods of f l u i d mechanics

provides s o l u t i o n s for c a l c u l a t i o n o f the f o r c e s produced on s t r u c t u r e s

by f l u i d s , tsunamis produce a number of s p e c i f i c problems which may not

g e n e r a l l y be considered. I t i s hoped t h a t t h i s paper, based on observations

of the e f f e c t s of tsunamis made along the northern C a l i f o r n i a coast during

the p a s t two decades w i l l contribute toward a b e t t e r tinder standing of the

damage produced by tsunamis, and a l s o w i l l a s s i s t persons engaged i n

design of c o a s t a l s t r u c t u r e s i n northern C a l i f o r n i a .

Although tsunamis have been studied s c i e n t i f i c a l l y for over a century,

i t i s only r e c e n t l y t h a t p r a c t i c a b l e design information i s becoming

a v a i l a b l e . Recent systematic s t u d i e s of tsunami generation and propagation

have been published by Wilson, l / 2/ Cox, 5/ and Wiegel 3/- A

Comprehen-s i v e Annotated Bibliography of TComprehen-sunamiComprehen-s haComprehen-s a l Comprehen-s o been publiComprehen-shed hj. Of

these p u b l i c a t i o n s , probably the b e s t s u i t e d t o the c o a s t a l engineer i s

Wiegel 3/.

Although tsunamis may be generated by a number o f causes, damaging

tsunamis are u s u a l l y produced from major seismic dlsturbajices. The

S T R U C T U R A L D A M A G E

Wiegel 3 / .

d i s c u s s e d by Wilson 1/ and by/ Recent tsimamis t h a t produced damage

along the northern C a l i f o r n i a coast are given i n Table 1 below.

T A B L E 1

Recent Tsunamis A f f e c t i n g the Northern C a l i f o r n i a Coast 7 / 8/ 2 / Northern R i c h t e r C a l i f o r n i a

Year Date Source tfagnitude

Dagg§2-19k6 1 A p r i l A l e u t i a n I s . 6.k

i960 22 May C h i l e 8.5

196k 27-28 March G u l f of A l a s k a 8.5

Van Dorn 6/ d e s c r i b e s the sotirce mechanism of the 27-28 tferch

tsunami as "generating a long s o l i t a r y wave which r a d i a t e d out o v e r the

P a c i f i c T-rLth v e r y l i t t l e d i s p e r s i o n . "

C h a r a c t e r i s t i c a l l y the tsunami waves generated have p e r i o d s (as

observed along the c o a s t ) ranging from about 5 t o 30 minutes. Ï^J^^se waves t r a v e l outward from t h e i r source w i t h a v e l o c i t y approximately g i ' ^ ^ ^

c = "i/gd where g i s the a c c e l e r a t i o n of g r a v i t y and d i s the ws-*®-^ depth.

Therefore, the wave v e l o c i t y i s dependent only on the depth o f •w^'tsr i n "the P a c i f i c

which the wave i s t r a v e l i n g . For the average depth of water i n ^

Ocean (about li|-,000 f e e t ) the corresponding v e l o c i t y would be 0X>o^'^ m i l e s per hour. I n deep water the tsi-nami waves are b e l i e v e d i:iC> be v e r y

low (say 1 to 2 f e e t high) and have a "length" measvured b e t w e e n

s u c c e s s i v e p o i n t s on the wave of between 50 to I50 m i l e s . T h u ^ ^ ship i n the open ocean would not be able t o n o t i c e a passing t s u n a m i - '

wave approaches the shore, the wave height I n c r e a s e s r a p i d l y d^'P^^^''^ °^

the wave c h a r a c t e r i s t i c s , the bottom topography, and the r e s o n ^ - ^ charac

^ ° C O A S T A L E N G I N E E R I N G

heights along any s p e c i f i c reach of s h o r e l i n e i s not f u l l y developed,

an order of magnitude i n c r e a s e from the deep ocean depths to the

shore-l i n e may he expected. T h i s probshore-lem i s under study by a number o f

t h e o r e t i c a l i n v e s t i g a t o r s and s i g n i f i c a n t c o n t r i b u t i o n s are being made

towards obtaining a fundamental understanding of the c h a r a c t e r i s t i c s o f

long period waves a t any given c o a s t a l l o c a t i o n . At the present time,

howerver, the only p r a c t i c a l method a v a i l a b l e f o r determining a design

tsunami height i s by obtaining the h i s t o r y of tsunamis a t the s i t e u n d e r

study. Such a h i s t o r i c a l study has been conducted f o r H i l o Harbor by

Doak Cox and published by Wiegel Zj.

Due to the complex nature of tsunamis, the p r e s e n t l y accepted metli<=^

f o r d e t a i l e d study of reduction of the damaging e f f e c t s of a tsunami 6.*

a s p e c i f i c l o c a t i o n i s by use of a h y d r a u l i c model. Such a model s t u d y

has been conducted f o r H i l o , Hawaii l o / . The s t r u c t u r a l damage produce

<3-a t H i l o h<3-as <3-a l s o been e x t e n s i v e l y documented both by the l&<3-amp;tlock R e e s e

and Matlock 11/ and a l s o by the U.S. Army Engineer D i s t r i c t , Honolulu, Hawaii 13/.

EEFTCTS OF RECENT TSUNAMIS IN NORTHERN CALIFORNIA

T h i s s e c t i o n contains observed e f f e c t s o f r e c e n t tsunamis along

the northern C a l i f o r n i a Coast. The e f f e c t s of the 19^6 tsunami were reported by Bascom 12/ and the Corps of Engineers l A / . E f f e c t s o f t h e

i960 and 1964 tsunamis were obtained by p e r s o n a l observation and extenes J - ^

intervievfs by Magoon 25/ and other Corps of Engineers personnel. With the exception o f two l o c a t i o n s t o be described l a t e r , r e c e n t

tsunamis along the northern C a l i f o r n i a coast have a l l e x h i b i t e d the

same g e n e r a l c h a r a c t e r i s t i c s . T h i s c o n s i s t s of a s e r i e s of r a p i d

undulations of the ocean surface reaching a maximum r a t e of change o f

S T R U C T U R A L D A M A G E

Generally, the major waves of the tsunami are experienced i n the

beginning of the disturbance, p a r t i c u l a r l y along the outer coast. The

e f f e c t i s o f t e n recorded along the coast for up to one week following

the i n i t i a l disturbance, but the waves are g r e a t l y reduced i n amplitude

by the second day. I n s i d e of San F r a n c i s c o Bay the tsunami has g e n e r a l l y

been about the same or lower than the t i d a l range. I n t h i s case, the

maximum water height i s reached when the tsunami i s i n the phase w i t h the

high t i d e .

Strong r e v e r s i n g ebb and flood currents are u s u a l l y observed to

occur simultaneously with the water l e v e l f l u c t u a t i o n s . These c u r r e n t s

are most severe i n l o c a t i o n s where water i s e i t h e r passing through a

c o n s t r i c t i o n or over a shallovr bottom.

At the mouths of the Koyo and Albion R i v e r s , the r i v e r s enter the

ocean a t the landward end of r e l a t i v e l y deep bays. Observers a t these

l o c a t i o n s i n 19&^ described an almost v e r t i c a l w a l l of water progressing

upstream, apparently s i m i l a r to a bore. At Noyo t h i s disturbance was

t r a v e l i n g upstream a t approximately 20 miles per hotir. The remaining p o r t i o n of t h i s s e c t i o n contains a summary of the p e r t i n e n t observed

c h a r a c t e r i s t i c s of and daznages produced from the tsunamis of 1 A p r i l 19^+6, 22 May I960 and 28 March 196!; along the northern C a l i f o r n i a coast.

The c h a r a c t e r i s t i c s of the t h r e e tsunamis mentioned as they

a f f e c t e d the northern C a l i f o r n i a coast are given i n Table 2. The s i t e numbers r e f e r r e d to i n Table 2 are located on Figure 1. The a f f e c t s o f the March 196'j- tsunami i n s i d e of San F r a n c i s c o Bay are given i n Table

TABLE a

SUMMARY OF RECENT TSUHAMIS ALONG MORTHERM CALIFORHIA COAST

S i t e Ho. S i t e

Maximum Time o f Nortli Water MnvimnTn Maximum l o c a t i o n L a t i - C o a s t a l E l e v a t i o n Wave Water (County) tude D e s c r i p t i o n Above HLLW Height L e v e l

-101 P o i n t Lobos MDnterey P o i n t Lobos t o

C a m e l (3) Monterey 102 P a c i f i c Grove (2) Monterey 103 Manterey Harbor (2) Mjnterey

( F e e t ) k6 60 6k Exposed c o a s t - - x Exposed c o a s t - - x Open cove 10.3 +7 +7 ( F e e t ) ( P S T ) 46 6o 64 46 6o m 64 46 60 64 Remarks 104 WOBB Landing Harbor (2) l o s s Landing t o C a p i t o l a Bbnterey Monterey S a n t a Cruz 201 C a p i t o l a P i e r (1) S a n t a Cruz 202 Santa Cruz Santa Cruz

Harbor (1) P r o t e c t e d harbor ( b r e a k v a t e r s ) P r o t e c t e d harbor ( J e t t i e s ) Exposed c o a s t Cove open t o south P r o t e c t e d harbor ( J e t t i e s )

+8 +7.5 0940 0330 X X 1,000 1964 damage: one t i e r o f s m a l l boats broke loose, o n l y minor damage. 1946 and 1964: v h i r l p o o l s a t seaward end o f Monterey breakwater, no damage. S p e c t r a l a n a l y s i s made o f I964 tsunami from p r e s s u r e gage by Marine A d v i s o r s I g / and a n a l y s i s and d i s c u s s i o n o f f l o a t and p r e s s u r e gage r e c o r d s by Wilson 16/.

- +7 9 - 1964 damage: one s k i f f broke a p a r t , ciurrents i n c h a n n e l s .

strong

- 12.4

14 0 0 0130 0 10 0 0

At s e a c l i f f Beach S t a t e Park maximum wave from +5 t o -1 MLLW. A t Hew B r i g h t o n Beach S t a t e Park, maximum wave from +5 t o -12 MLLW (1964)

0 0 100,000 (Constructed 1962). I964 damage c o n s i s t e d o f t h e l o s s o f a dredge ami c a b i n c r u i s e r i d i i c h broke l o o s e d u r i n g tsunami. MEiJor e f f e c t was strong c u r r e n t s . Wave gage recorded wave not l e s s than 7.5 f e e t , obsearvers r e p o r t e d 10-foot wave w i t h minimum e l e v a t i o n about -8 MLLW. Most boats and f a c i l i t i e s i n harbor undamaged.

TABLE 2

SUMMARY OF RECEHT TSUHAIOS ALOMG NORTHERN CALIFORNIA COAST

S i t e Ho. S i t e Horth L o c a t i o n L a t i -(County) tude C o a s t a l D e s c r i p t i o n Maxlfflum Time o f Water Maximum ^Èüc^I^um E l e v a t i o n n -5 Wave Water Above MLLW-"-Height L e v e l f 203 S a n t a Cruz (1) Santa Cruz (3) t o Martin's Beach 301 Martin's Beach (1) Martin's Beach t o H a l f Moon Bay (k) 302 H a l f Moon Bay Harbor (1) 303 P a o i f i c a ( S h e l t e r Cove) (1) 14-00 Golden Gate ( P r e s i d i o ) 501 Malr Beach (1) 502 S t l n s o n Beach (1) 503 B o l l n a s ( 1 ) 505 Tomales Bay • m 50l(. Drakes Beach, Bay (1) Santa Cruz Santa Cruz San Mateo San Mateo San Mateo San Mateo San Mateo San F r a n c i s c o Marin Marin Marin Marin ( F e e t ) ( F e e t ) (PST) 46 60 64 46 60 64 46 60 Damage 64 46 60 64 Cove open t o south Exposed c o a s t Very s m a l l exposed cove Exposed c o a s t 12.4 6 10^ 1,000 P r o t e c t e d Harbor I 5 I I. 5 1 0 . 1 1 7 . 3 ( b r e a k w a t e r s ) Very small exjrased cove E n t r a n c e t o bay Coves open t o south Coves open t o south Coves open t o south Bay w i t h m m i r e s t r i c t e d Cove open t o south 6.5 7 . 2 8 9 -5.8 6.5 8.4 1.7 2.9 7.4 8 § 0100 13-4 - 9 6.5

-1964 and 1946, one l i f e l o s t due person b e i n g trapped i n cave d u r i n g tsunami and subsequently drowned.

X Tsunami always h i g h e r a t n o r t h end o f cove. Minimum e l e v a t i o n -10 MLLW.

X 1964, two o b s e r v e r s r e p o r t e d u n u s u a l lows reached by tsunami.

1,000 Low wave h e i g h t i n 1964 probably caused by c o n s t r u c t i o n o f harbor

San F r a n c i s c o Bay A r e a - See T a b l e 3.

1946 Wave c u t through lagoon b a r .

1964, one l i f e l o s t by drowning on Duxberry Reef 29 March I964

6,000 1964, 25 mph c u r r e n t r e p o r t e d , i960 and 191^6, Btrocg c u r r e n t s r e p o r t e d . 1964, dsmageB

S i t e Ho. S i t e Horth l o c a t i o n L a t l -(County) tude 506 M a r s h a l l (1) 507 508 Jensen Oyster Beds (1) I n v e r n e s s Yacht Cluh (1) 601 Bodega Bay I n s i d e entrance (1)

602 Bodega Bay, H.E. s i d e (2) 603 Salmon Creek Beach (1) 604 Jenner Beach ( l ) Jenner t o G u a l a l a (3) 605 G u a l a l a E l v e r Bar (1) 700 Arena Cove (1) 701 P o i n t Arena L i g h t S t a t i o n (1) Marin Marin Msrln Sonoma Sonoma Sonoma Sonoma Sonoma Mendocino Mendocino l A B L E 2 (Continued)

SUMMARY OF RECEHT TSUHAJGS ALONG NORTHERN CALIFOEHIA COAST Maxijnum Time o f

Water Maximum Maximum C o a s t a l E l e v a t i o n a , b Wave Water

D e s c r i p t i o n Ahove MLLff ~ Height L e v e l - , Damage ( F e e t ) ( F e e t ) f p s i ) ( f l 46 60 .64 46 60 64 46 60 64 46 60 64 P r o t e c t e d bay - - - - - 2 - - - - - x P r o t e c t e d bay - - - - - 2 - - - - - x P r o t e c t e d bay - - - - _ . _ x Bey w i t h - - - - 2 5 . . olOO - - 2,000 entrance J e t t i e s Bay v i t h - - - x x l - - - x x x entrance J e t t i e s

Exposed beach - - 12e - - - - - - . - x

Exposed s h a l l o w - - l o e - - - - - - - x x cove Exposed c o a s t - - - - - - - _ - x x Exposed - - - - - - - - - - X X s h a l l o w cove Exposed cove l 4 - - 1 6 - 1 2 - - - x x x Exposed p o i n t - - 12e - - - - - - - x x rrotertecl cove - - 8.8 x x Remarks 1964, damage t o n a v i g a t i o n a l a i d s . 1946, i960, 1964, strong c u r r e n t s r e p o r t e d i n entrance; 1964 r e p o r t e d 8 k n o t s .

1964, fisherman on beach r e p o r t e d t h a t wave reached e l e v a t i o n h i g h e r than u s u a l h i g h t i d e p l u s runup r e s u l t i n g I n l o s s o f f i s h c a t c h . 1964, no e f f e c t I n R u s s i a n R i v e r .

i960, two waves washed over b a r a t mouth i n t o G u l a l a R i v e r .

1964, maximum wave progressed about 500 y a r d s iTito L i t t l e S i v e r (from moutb. a t beach").

I

TABLE 2 (Continued)

SUMMARY OF RECENT TSUNAinS ALOHG NORTHERN CALIFORNIA COAST

S i t e Ho. L o c a t i o n (County) n o r t h L a t i -tude C o a s t a l D e s c r i p t i o n 703 R u s s i a n Gulch S t a t e Park (1) Mendocino 704 A l b i o n R i v e r (2) Mendocino 705 Koyo R i v e r (4) Mendocino 801 S h e l t e r Cove Humboldt 802 Humboldt Bay Humboldt

803 U.S.G.S. S t a t i o n Humboldt Horth s p i t (1)

804 M i n i c i p a l Marina (1) Humboldt 805 King SaOmon Humboldt

(Entrance t o King Slough) (1) Maximum Water E l e v a t i o n Above MLLW (F5St) 46 60 .64 Maximum Wave Height ( F e e t ) (PST) 46 6o 64 46 6o Time o f Maximum Water^ L e v e l - Damage Remarks "TfT 64 46 60 64 P r o t e c t e d cove C o a s t a l r i v e r ; 100-foot wide mouth C o a s t a l r i v e r ; 150-foot v i d e entrance 11.2 11.3 9 12.6 13 - 1140 P r o t e c t e d cove Bay w i t h entrance J e t t i e s 4e 9e - - 12 12.4

500 1964: Observers r e p o r t e d 4 o r 5 low bores t r a v e l e d up r i v e r making a loud n o i s e . C u r r e n t s scoured out r i v e r mouth. E f f e c t o f wave was f e l t a t l e a s t 1-1/4 m i l e up r i v e r from entrance. Damage was due t o d e l a y s t o f i s h i n g v e s s e l s .

124,000 1964: Observers r e p o r t e d t h a t second and t h i r d waves progressed up r i v e r from mouth l i k e a bore w i t h t h e forward f a c e c o n s i s t i n g o f a s e r i e s o f s m a l l s t e p - l i k e Jumps. Wave t r a v e l about 35 mph. Damage t o b o a t s f l o a t i n g s t r u c t u r e s .

1964: 14 ( e s t i m a t e d ) knot c u r r e n t and 6-foot change i n water l e v e l i n about 20 minutes i n channel opposite o f s t a t i o n .

Strong c u r r e n t s i n entrance i960 and I964.

i

>

>

TABLE 2 (Continued)

SUMMARY OF RECENT TSUNAMIS ALONG NORTHERN CALIFORHIA COAST

S i t e No. North L o c a t i o n L a t l -(County) tude Maximum Time o f Water Maximum MpvTrnnm C o a s t a l E l e \ r a t l o n a,b Wave Water D e s c r i p t i o n Above MLLW Height L e v e l -'"

806 P.G.i E . Pover P l a n t Humboldt (0.6-Mlle upstream o f entrance t o King Slough) (1) 8OT T r i n i d a d (1) Humboldt T r i n i d a d t o Klamath Humboldt R i v e r (5) D e l Norte 901 Klamath R i v e r D e l Norte

Requa Boat Dock D e l Norte (1) (O.T-mile above mouth)

Panther Creek Lodge (1) (1 m i l e from mouth) Chinook T r a i l e r Court (1) (1.6 m i l e s above mouth) Deans Camp 0.7 Mile (1) South o f e n t r a n c e D e l Norte D e l Norte D e l Norte ( F e e t ) 46 60 64 ( F e e t ) ( P S T ) 46 60 64 46 60 Damage 1¥V 64 46 60 64 9-7 0005 P r o t e c t e d - - 1 8 cove Exposed cove - - - _ . _ x C o a s t a l r i v e r w i t h r e s t r i c t e d entrance

- - - 4,000 1964: Damage t o boat dock and boats strong c u r r e n t s .

- - - - - - - - - - 1964: Strong c u r r e n t s ; water l e v e l "3 f e e t above normal h i g h t i d e . " - - - - - - - - . - - 200 1964: Damage t o boat dock and b o a t s

- - - X 17/ 1964: Water l e v e l "2 f e e t above normal h i g h t i d e )

i

TABLE 2 (continued) SDMMART OF BECEBT TSUHAMIS ALOHG HORTHERN CALIFORHIA COAST

S i t e No. S i t e North L o c a t i o n L a t i - C o a s t a l (County) tude D e s c r i p t i o n Maximum Time o f Water Maximum Maximum E l e v a t i o n a^b Wave Water

above MLLW Height L e v e l £ Damage Remarks

90a C r e s c e n t C i t y

903 Pebble Beach (2) D e l Morte 904 P e l i c a n Beach (1) D e l Morte 905 Smith R i v e r (1) D e l Horte (0.3 m i l e above mouth) ( F e e t ) 46 60 64 ( F e e t ) (PST) 46 60 64 46 60 64 46 60 64 Improved harbor - I8.5 20.7 10+ 28e see remarks

Exposed beach Exposed beach C o a s t a l R i v e r , 300-foot v i d e mouth - 15 - 13.3 - 6,000

I96O: $30,000 damage confined t o C i t i z e n s Dock a r e a and d e b r i s i n s t r e e t s 1964: Tsunami produced major damage a t

C r e s c e n t C i t y c o n s i s t i n g o f an e s t i -mated $11,000,000 11/ t o t h e v a t e r

-f r o n t and downtown a r e a s . I n a d d i t i o n , 8 l i v e s were l o s t .

Driftwood stranded on beach backshore not moved by tsunami Damage t o f l o a t i n g s t r u c t u r e s , strong c u r r e n t s i n r i v e r , water l e v e l h i g h e r on r i g h t bank than on l e f t S3

1

>

HOTE; see page 7 f o r legends

0 5

Legend:

TABLE 2 (continued)

SUMMARY OF BECEMT TSUHAMIS ALOMG HOBTHERM CALIFOBMIA COAST

- Ho d a t a a v a i l a b l e . O

P

X ObserverB noted no e f f e c t s or damage. g

( ) number o f i n t e r v i e w s , 196k. ^ f

e Estimated from v e r y g e n e r a l d e s c r i p t i o n ,

M

a Maximum h i g h water e l e v a t i o n s shown t o t h e t e n t h o f a ^

f o o t have a probable a c c u r a c y o f + 1 f o o t . Q

b Maximum h i g h water e l e v a t i o n s shown t o t h e whole f o o t S

have a probable acc\jracy o f + f e e t . ^

c Times g i v e n a r e i n P a c i f i c Standard Time. 46 i s a c t u a l l y Q

1 A p r i l 1946; 60 I s a c t u a l l y 23 May I96O; and 64 i s a c t u a l l y 3

28 March 1965. W

15/ Msa-lne A d v i s o r s , A Broad-Frequenoy-Band wave Study a t Monterey Harbor, C a l i f o r n i a J u l y 1964 (U.S. Army C o n t r a c t Ho. nA-04-203-CIVENG-64-7)

16/ Wilson, B a s i l , P r o g r e s s Reports, Surge Study f o r [fcnterey Bay and Harbor, C a l i f o r n i a . (U.S. Ar^y C o n t r a c t DA-22-079-CIVEHG-65-10)

17/ C l i f t o n , P a u l , P e r s o n a l Communi c a t i o n fi-om Information compiled by S t a t e o f C a l i f o r n i a , 1964.

S T R U C T U R A L D A M A G E 47

I n general, these f i e l d i n v e s t i g a t i o n s were made i n an attempt to

determine the monetary value of damage caused by the tsunami, the

maximum e l e v a t i o n a t t a i n e d by the tsunami and the c h a r a c t e r l c s of the

highest wave. With the exception of the reports of a b o r e l i k e d i s t u r

-bance a t the entrance to the Noyo and Albion R i v e r s ( s i t e s 70h and 705)

observers have reported t h a t the tsunami was s i m i l a r to a t i d e , but with

g r e a t l y a c c e l e r a t e d v e r t i c a l movement and h o r i z o n t a l c u r r e n t s . A check

was a l s o made of a l l U.S. Geological Survey c o a s t a l stream gage records

i n northern C a l i f o r n i a t h a t might have shovm the tsunami. No i n d i c a t i o n of

the tsunami was found on amy of the records.

With the exception of Crescent C i t y i n I964 and p o s s i b l y Half Moon Bay i n 19k6, a l l damage reported has been to commercial f i s h i n g or

pleasure c r a f t and t h e i r a s s o c i a t e d shoreside f a c i l i t i e s caused by

unusually s w i f t h o r i z o n t a l c u r r e n t s . A t y p i c a l example of a l o c a t i o n

s u b j e c t to damage by h o r i z o n t a l currents i s Santa Cruz Harbor, shown i n Figure

k. During the 196k tsunami the water l e v e l v a r i e d from a high of 11 f e e t to a low of about -8 f e e t MLLW. During the major portion of the drop i n elevation, the water l e v e l dropped at a r a t e of aboat one foot a minute

for about 10 minutes. Obviously, strong h o r i z o n t a l c u r r e n t s were produced by t h i s disturbance. A f l o a t i n g h y d r a u l i c dredge xras docked

near the entrance j u s t before the tsunami a r r i v e d . One of the e a r l y waves

Induced such a drag on the dredge t h a t the mooring l i n e s parted and the

dredge was swept seaward. As i t moved out the entrance, i t s t r u c k the

east j e t t y and f i n a l l y sank along the entrance channel and on the c e n t e r

oo TABLE 3

E F F E C T S OF KIRCH 196ii TSUHAÏI i n SAN FR.UICISCO BAY

L o c a t i o n S i t e Kaxiinum ./ater Maximum S i t e E l e v a t i o n V/ave Number ;bove MLLW H e i g h t ( F e e t ) ( P S T ) Time o f Maximum Vave Damage 7 5 ) 0130 None 4. 0200 4 0200 100,000 5 0200 None 7,500 (0100-0200) 5 0200 Max. 10,000 60,000 None None None None None None None Remarks

San F r a n c i s c o Golden Gate A S a u s a l i t o Baum,an B r o s . S a l e s I 6 S a u s a l i t o M a r i n s h i p Y a c h t H a r b o r 18 J a u s a l i t o C l i p p e r Y a c h t H a r b o r 19 B e l v e d e r e S a n F r a n c i s c o Y a c h t C l u b 22 San R a f a e l San R a f a e l Y a c h t H a r b o r 31 San R a f a e l L o w r i e s Y a c h t H a r b o r 36 San R a f a e l L o c h Lomond H a r b o r 39 V a l l e j o Mare I s l a n d N a v a l S h i p y a r d G V a l l e j o G l e n Cove H a r b o r 103 B e n i c i a B e n i c i a 6 S u i s u n P a u l ' s Y a c h t H a r b o r 105 ;intiooh B i g B r e a k R e s o r t 52 A n t l o o h L a u r i t z e n Y a c h t H a r b o r 53 .Intiooh B r i d g e M a r i n a 55 . m t l o c h S a n J o a q u i n Y a c h t Harbor 57 ( F e e t ) 5.5 S. 6.6 .55 S l i g h t O.J, None None None None R e c o r d i n g gage Damage t o f l o a t i n g s t r u c t u r e s and b o a t s . Damage t o f l o a t i n g s t r u c t u r e s and b o a t s . D.amage t o f l o a t i n g s t r u c t u r e s and b o a t s . One l a r g e p l e a s u r e boat broke l o o s e c a u s i n g damage t o o t h e r b o a t s and f l o a t i n g f a c i l i t i e s . R e c o r d i n g gage. F i s h stopped b i t i i c -O

i

>

TABLE 3 ( C o n t i n u e d )

E F F E C T S OF I'ARCE TSUK,U!I i n SAN FRANCISCO B A I

L o c a t i o n S i t e S i t e Number Maximum .Vater E l e v a t i o n Above >XL:V Maximum vJave H e i g h t Time o f >iaicimum '.feve Damage R e n a r k s ( F e e t ) ( F e e t ) ( F S T ) (.$)

A n t l o c h Tommie's Y a c h t H a r b o r 57 None None

A n t i o c h J a y ' s Sc Dee's H a r b o r None None

P i t t s b u r g P i t t s b u r g M a r i n a 107 None None

McAvoy H a r r i s Y a c h t H a r b o r 59 None None

McAvoy Mc.ivoy H a r b o r 66 None None

C r o c k e t t E c k l e y ' s R e s o r t 62 None None C r o c k e t t D o w r e l i o ' s H a r b o r 63 None None

Rodeo Rodeo M a r i n a 64 None None

F t . San P a b l o S t a n d a r d O i l Company 66 7.4 0150 None E f f e c t s l a s t e d about 10 d a y s . P t . San P a b l o P t . San P a b l o Y a c h t H a r b o r 65 5.5 6 t o 6.5 0200 None L i k e f a s t t i d e .

P t . Richmond Red Rock M a r i n a 7 ( e s t . ) A f t e r 1; :30 None B o a t s t o u c h bottom. Richmond Richmond Y a c h t S e r v i c e 67 5.5 t o 6 1.5 None

Richmond Eichmond Y a c h t H a r b o r 68 +6 7 None L o u w a t e r t o -1 tlLLi'/, Richmond C h a n n e l M a r i n a 70 +6 9 Not e v a l - Low w a t e r t o -1 MLL^.

03

i

U I O

TABLE 3

( C o n t i n u e d )

E F F E C T S OF M;\HCH 1964 TSUIIAJH i n S.UI FRANCISCO BAT Maxiimam L o c a t i o n S i t e S i t e Number •Jater E l e v a t i o n Above MLLU Maximum Wave Heie-ht Maximum

Wave Damage Remarks ( F e e t ) ( F e e t ) (PST) ( $ )

B e r k e l e y B e r k e l e y l a o h t H a r b o r 71 02/t0 100 Damage l o w b e c a u s e emergency crews on hand B e r k e l e y

t o a d j u s t l i n e s . lOK c u r r e n t i n e n t r a n c e . O a k l a n d Norwalk Y a c h t H a r b o r 72 +6.4 7.4 0 U 5 None Low w a t e r t o -1 MLLW.

O a k l a n d Jack London I'iarina 112 +6 7 None Low w a t e r t o -1 MLLW. O a k l a n d Embarcadero Y a c h t Harbor +6 8 None Low w a t e r t o -1 >]LL./. O a k l a n d Hans G l a r i e r Boat S e r v i c e None None None

Oakland O a k l a n d M a r i n a 77 +7 Hone

Oakland L a n i K a i H a r b o r S l +2 None

Oaldand O a i a a n d Y a c h t C l u b SO None

O a k l a n d N o r d i c Yacht. I m p o r t s None

O a k l a n d Tompkin Boat. S a l e s 112 None

O a k l a n d E v a n s R a d i o Dock None

Alameda Bay Y a c h t S e r v i c e None

Alameda P a c i f i c M a r i n a 74 Hone

-Uajieda Alameda Y a c h t C l u b 73 None

T I B L E 3

( C o n t i n u e d )

E F F E C T S OF >uiECH 1964 TSUNAJ-tt i n SAN FRMICISOO 3 A I

L o c a t i o n S i t e S i t e Number Maxim-um •h^ e r E l e v a t i o n Above IXT,./ Maximum •..'ave Maximum.

H e i r h t Wave Damage Remarks ( F e e t ) (Feo+) (PST)

Snn Le.indro San L e a n d r o M a r i n a 115 None

A l v i s o A l v i s o K a r i n a 117 None

l a l o A l t o P a l o A l t o Y a c h t H a r b o r 2 None

Redwood City- Redwood C i t y Muni. None

Redwood C i t y Redwood M a r i n a 3 None

Redwood C i t y P e t e ' s H a r b o r 5 None

B u r l l n g a n e Coyote P'oint H a r b o r 8 None

S o u t h San F r a n c i s c o O y s t e r P o i n t M a r i n a 118 None

A l v i s o E n t r a n c e t o A l v i s o S l o u g h C 1.1 None R e c o r d i n g gage. ( S a n t a C l a r a County) Alameda N a v a l A i r S t a t i o n , Alameda D 5.4 None R e c o r d i n g gage. (U.S.C. & G.S.) Richmond S t a n d a r d O i l Company F 4.0 None R e c o r d i n g gage. ( s t a n d a r d O i l Company) B e n i c i a B e n i c i a H a r b o r E 0.4 None R e c o r d i n g gage. ( s t a t e Department o f

Water R e s o u r c e s )

C o l l i n s v i l l e and beyond

I L e s s t h a n 0.1

None R e c o r d i n g gage. ( s t a t e Department o f Water R e s o u r c e s )

52 C O A S T A L E N G I N E E R I N G

c r u i s e r struck a submerged object (presumably the sunken dredge) w h i l e

attempting to leave the harbor, and i t a l s o sank. The strong currents

Induced by the tsunami a l s o caused movement of the m a t e r i a l i n the

entrance channel bottom. S e v e r a l small f l o a t s located near the p u b l i c

p i e r were damaged due to being caught against the p u b l i c p i e r and were

wrecked or t w i s t e d as the water f e l l . With the exception to the damage

to the small f l o a t s mentioned above, a l l other f l o a t i n g f a c i l i t i e s

with-stood the tsunami.

I n s i d e of San F r a n c i s c o Bay both t h e May 1960 and March 196h tsimamis were g r e a t l y attenuated a f t e r passing through the Golden Gate. Based on

v e r y l i m i t e d data, a tstuiami i s reduced to one-half the height a t the

Golden Gate a t Richmond on the north and Hunter's Point on the south. A

tsunami i s reduced to l e s s than one-tenth the height a t the Golden Gate

at the e a s t e r l y end of San Pablo Bay and A l v i s o on the south. These v a l u e s

are shown on F i g u r e h . Damage I n San F r a n c i s c o Bay was l a r g e l y to p l e a s u r e

boats. The highest damage was reported from Miarlnas i n Marin Coxmty where

strong c u r r e n t s caused boats and i n some cases portions of f l o a t i n g s l i p s

to break l o o s e . These o b j e c t s a t t a i n e d the v e l o c i t y of the moving water

and caused damage when they s t r u c k other c r a f t .

At Noyo Harbor ( s i t e 705, a l s o see Figure k ) the entrance i s r e s t r i c t e d , but the harbor i s a l s o r e s t r i c t e d and the f u l l a f f e c t s of

the wave were f e l t over the e n t i r e reach of the harbor. I n the March 196h

tsunami the f i r s t wave r o s e r e l a t i v e l y slowly, and exhibited the c h a r a c t e r

-i s t -i c s as observed elsewhere along the coast. The second wave o c c u r r -i n g

about 15 minutes a f t e r the f i r s t , formed a b o r e - l i k e face, about 7 f e e t high, c o n s i s t i n g of a s e r i e s of s t e p - l i k e jumps. One observer saw the

S T R U C T U R A L D A M A G E

bore form a t the entrance and r a p i d l y drove h i s automobile

p a r a l l e l to the t r a v e l of the bore, but was unable

to pass i t . At Noyo, damage was to f l o a t s and to ccmmerclal f i s h i n g

v e s s e l s t h a t broke loose during the tsunami.

Due to the r e l a t i v e l y severe tsunami damage produced a t Crescent

C i t y i n 1964, an i n v e s t i g a t i o n was made of the coast on both s i d e s of Crescent C i t y to determine the water l e v e l s reached by the tsunami.

Based on e l e v a t i o n s determined a t l o c a t i o n s p o s i t i v e l y i d e n t i f i e d as

those caused by the tsunami, i t i s concluded t h a t the runup e l e v a t i o n

reached by the t h i r d wave ( f i f t h wave of Tudor 18/) of t h i s tsunami was e s s e n t i a l l y constant a t the shore f o r a d i s t a n c e of almost 2 m i l e s southwest of Crescent C i t y and probably only s l i g h t l y diminished f o r

1 mile northeast of Crescent C i t y . T h i s high water e l e v a t i o n along the shore reached 20 to 21 f e e t above MLLW. The l i n e of maximum tsunami inundation, as shoim on Figmr'e 6 g e n e r a l l y followed the +20 MLLVf contour where the ground e l e v a t i o n s increased to lemdward from the

shore. T h i s would include most of downtown Crescent C i t y and the pasture

land i n the v i c i n i t y of mm No. 5.

A d e f i n i t e departure from t h i s c h a r a c t e r i s t i c runup p a t t e r n was

found where the ground e l e v a t i o n decreases to seaward from the coast and

e i t h e r decreases or remains e s s e n t i a l l y l e v e l landward from t h e c o a s t .

Under t h i s condition, water flowed over the narrow c o a s t a l dunes or

r a i s e d areas near S t a t e Highway 101 i n a s i m i l a r manner as water flowing over a broad w e i r . Apparently the quantity of water t r a n s p o r t e d landward

54 C O A S T A L E N G I N E E R I N G

low areas to landward thus reducing the runup. T h i s condition was reported

both i n the a r e a of HVM 316 and a l s o at HVM's 1 and 2 shown on Figure 6.

A d e t a i l e d p r e s e n t a t i o n of the depths of submergence ( i n f e e t )

b u i l d i n g s known to have been destroyed i n the downtown s e c t i o n of C r e s c e n t

C i t y during the ig6k tsunami are shown on Figure 7. The water depth s e r v a t i o n s were taken by experienced flood damage crews w i t h i n the f i ^ ^ ^

two weeks a f t e r the tsunami. The survey on which these water depth e l e v a

-t i o n s are superimposed was made i n I965, approximately 1 year l a t e r ^^^^ show man-made changes i n topography. With the exception of the b u i l ^ " ^ ^ '

no s i g n i f i c a n t departures have been made from the 196k topography. B ^ x l d

-ings shown as shaded were a t o t a l l o s s . B u i l d i n g s shown as l o s t a r © taken

from Corps o f Engineers c o n t r a c t f i l e s f o r removal o f debris, a e r i a l - P^""*^""

graphs taken on 1 A p r i l 196h and ground photographs taken s h o r t l y af"^^^^

tsunami. Arrows i n d i c a t e the d i r e c t i o n of movement of b u i l d i n g s . A d d i t i o n a l

sheets covering the e n t i r e c o a s t a l area inundated i n the v i c i n i t y Crescent

C i t y have a l s o been prepared by the U.S. Army Engineer D i s t r i c t , S a O FTBUCXSCO.

Damage at Crescent C i t y has already been reported on i n numero^i®

papers and p u b l i c a t i o n s I 8 , 2$, 20, 21, 22, 23, 2k_, 26, 27/. I n eiö.<^^^°^' the two Crescent C i t y newspapers, the Crescent C i t y American, the I ? ^ - ^

Norte T r i p l i c a t e i n Crescent C i t y , and the Humboldt Times i n Eureke^:'

C a l i f o r n i a , have published a number of e x c e l l e n t photographs of d a i o ^ ^ ®

S T R U C T U R A L D A M A G E 55

STRUCTURAL DAMAGE AT CRESCENT CITY

f r o m t s u n a m i o f M a r c h 1961+

S t r u c t u r a l damage a t Crescent C i t y i s discussed and i l l u s t r a t e d

by the above referenced authors. I n searching f o r the reasons f o r the

s e v e r i t y of damage a t Crescent C i t y , i t should be remembered t h a t the

primary i n d u s t r y of the northwestern p o r t i o n of the S t a t e i s the

production of commercial lumber. Thus the m a j o r i t y of b u i l d i n g s are o f

wood frame construction, many of which appeared to have been b u i l t a

number of years ago. P r i o r to the tsunami, the c o a s t a l a r e a t o the s o u t h

-e a s t of Cr-esc-ent C i t y and a l s o th-e harbor s h o r -e l i n -e w-er-e cov-er-ed w i t h

v a s t q u a n t i t i e s of timber d e b r i s , i n c l u d i n g l a r g e logs and t r e e stumps.

A t y p i c a l view of the d e b r i s south of Crescent C i t y i s shown on S l i d e 1.

F i g u r e 8 snows the harbor area about 2 years before the tsunami. F i g u r e 9 shows the harbor one week a f t e r the tsunami. N o t e the i n c r e a s e d width of the s m a l l creek i n the harbor and a l s o the erosion edars along "t^®

beach. Severe damage was observed i n areas where the tsunami exceeded

k to 6 f e e t above the ground siArface (see F i g u r e 7 ) . The water depth reached or exceeded 6 f e e t along the e n t i r e length of Front S t r e e t , and about nine blocks of the main portion of Crescent C i t y . The m a j o r i t y

of the one s t o r y wood frame structiffes i n t h i s a r e a were e i t h e r t o t a l l y

destroyed or damaged to such an extent t h a t they were a menace to p u b l i c

h e a l t h and had to be t o r n down.

I t i s the opinion of the w r i t e r t h a t the m a j o r i t y

of s t r u c t u r a l damage a t Crescent C i t y was the r e s u l t of one or a combina.'*'^"'^

56 C O A S T A L E N G I N E E R I N G

The f i r s t , and probably t h e most damaging, was t h e impact o f logs

and other o b j e c t s such as automobiles or baled lumber d i r e c t l y on

s t r u c t u r e s .

T h i s d e b r i s caused damage by e i t h e r destroying the load c a r r y i n g

c a p a c i t y of w a l l s or by bending or breaking r e l a t i v e l y l i g h t unprotected

columns and allowing subsequent f a i l u r e . As pointed out by Matlock e t a l

U / t h e e f f e c t o f debris i s h i g h l y indeterminate. For exan^le, the d e b r i s

may build-up i n f r o n t o f a s t r u c t u r e to such an extent t h a t t h e d e b r i s

a c t u a l l y forms a s h i e l d f o r f u r t h e r damage, or the increased a r e a

r e s u l t i n g from t h i s d e b r i s may r e s u l t i n s u f f i c i e n t f o r c e from t h e tsunami

to cause the e n t i r e s t r u c t u r e t o be swept away. As mentioned e a r l i e r ,

ob-s e r v e r ob-s reported t h a t t h e inundation from the tob-sunami roob-se r e l a t i v e l y

g r a d u a l l y and d e f i n i t e l y not r e s u l t i n g i n a bore as described a t H i l o

Hawaii, by Matlock e t a l 1 1 / .

Structiu-es t h a t were i n s u f f i c i e n t l y anchored ( g e n e r a l l y on

non-continuous f o o t i n g s ) f l o a t e d o f f t h e i r foundations and were s e r i o u s l y

wrecked or rendered u s e l e s s when they f i n a l l y s e t t l e d on t h e ground.

The t h i r d major cause of l o s s was the general l a c k o f r e s i s t a n c e

to h o r i z o n t a l forces i n many s t r u c t u r e s , normally provided by shear w a l l s

i n b u i l d i n g s and c r o s s bracing i n open-pile s t r u c t u r e s .

Generally, the more s u b s t a n t i a l l y constructed s t r u c t u r e s , p a r t i c u l a r l y

m u l t i s t o r y wood, hollow block and r e i n f o r c e d concrete, withstood t h e

tsunami. These s t r u c t u r e s required considerable i n t e r n a l r e f u r b i s h i n g

S T R U C T U R A L D A M A G E 57

One p a r t i c u l a r l i g h t h u i l d i n g shown on S l i d e 7* was located seaward of Front S t r e e t at D S t r e e t . T h i s s l i d e , taken s h o r t l y a f t e r

the tsunami, shows the high water mark on the s t r u c t u r e . Note t h a t the

windows are s t i l l i n t a c t . I t i s b e l i e v e d t h a t the reason t h a t such an

obviously l i g h t b u i l d i n g i s s t i l l standing when other s i m i l a r b u i l d i n g s

were destroyed i s t h a t i t i s r i g i d l y held down to the foundation and t h a t

i t was not s t r u c k by any major p i e c e s of d e b r i s .

CONCLUSION

No s p e c i f i c conclusions were reached i n t h i s study regarding

p a r t i c u l a r design c r i t e r i a to be followed i n designing s t r u c t u r e s to

r e s i s t tsunamis. I t i s obvious t h a t i f s t r u c t u r e s must be constructed

i n p o r t i o n s of the coast subjected to tsunamis, care must be taken to

provide f o r s u f f i c i e n t l a t e r a l r e s i s t a n c e to allow the struct\are to

withstand the b a t t e r i n g of flowing water and heavy d e b r i s . Vfiegel 18/

suggests t h a t m u l t i s t o r y b u i l d i n g s be designed so t h a t even though the

f i r s t f l o o r i s completely swept away, the supporting columns a r e s u f f i c i e n t

to r e t a i n the s t r u c t u r a l i n t e g r i t y of the b u i l d i n g . Consideration should

a l s o be given so as to prevent the s t r u c t i i r e (or a p o r t i o n t h e r e o f ) from

f l o a t i n g and subsequently being swept away or wrecked. T h i s i s p a r t i c u l a r l y

important i n light-vrood frame b u i l d i n g s where a w e l l designed foundation

and tie-downs are e s s e n t i a l .

C O A S T A L E N G I N E E R I N G

L i s t of References

Wilson, B a s i l W.j Web, Louis M.; and Hendrlckson, James A.; The Nature of Tsunaniis, T h e i r Generation and D i s p e r s i o n i n Water o f F i n i t e Depth; National Engineering Science Company, August

1962-Wilson, B a s i l W., Propogation and Run-up of Tsunami Waves, Natl"^''' Engineering and Science Company, March 196*+.

Wiegel, Robert L., Oceanographlcal Engineering, P r e n t i c e - H a l l , -'-^^ ' Pages 95-108.

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Van Dorn, William G., Soinrce Mechanism the Tsunami of {«farch 2&:> ^ r i S i n Alaska, Proceedings of the 9 t h Conference on C o a s t a l Engine®-"^

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Shepaxd, F. P., Macdonald, G. A. and Cox, D. C , The Tsunami

1 A p r i l I9I16, B u l l e t i n of the Scripps I n s t i t u t e of O c e a n o g r a p h y ' Volume 5, No. 6, pp 391-582, I95O.

Symons, J . M. and Z e t l e r , B. D., The Tsunami of 22 May I 9 6 0 , s - ^ recorded a t t i d e s t a t i o n s . P r e l i m i n a r y Report, U.S. Departmen'*^ Commerce, Coast and Geodetic Survey, Washington, D.C.

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Geodetic Survey.

recorded a t t i d e s t a t i o n s , U.S. Department of Commerce, Coast

Palmer, R. Q., e t . a l . Hilo Harbor Tsunami Model - R e f l e c t e d superimposed, ASCE S p e c i a l t y Conference on C o a s t a l E n g i n e e r i n g ^ Santa Barbara, October I 9 6 5 .

Matlock, H., Reese, L. C , and Matlock, R. B., A n a l y s i s of

S t r u c t u r a l Damage from the 1960 Tsunami a t H i l o Havraili, Struc-*^"" ^ Mechanics Research Laboratory, University, of Texas, Balcones f ^ ^ ^ "

Center, Austin, Texas ( I 9 6 2 ) , ^ s t ,

Basoom, V/illard N., E f f e c t of Seismic Sea Wave on C a l i f o r n i a C^'^ U n i v e r s i t y of C a l i f o r n i a F l u i d Mechanics Laboratory, B e r k e l e y

C a l i f o r n i a , I9U6.

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S T R U C T U R A L D A M A G E 59

L i s t of References (Continued)

l y U.S. Army Engineer D i s t r i c t , San F r a n c i s c o , Report on Survey of . Damages, T i d a l VJave of 1 A p r i l 19h6, San F r a n c i s c o , C a l i f o r n i a , 19^ ' 15/ Marine Advisors, A Broad-Frequency-Band Wave Study a t Monterey

Harbor, C a l i f o r n i a , J u l y 196k, (U.S. Army Contract Ho. DA-04-203 '

CIVENG-6i;-7)

16/ Wilson, B a s i l , Progress Reports, Siarge Study for Manterey Bay and Harbor, C a l i f o r n i a (U.S. Army Contract DA-22-079 - CIVENG-65-IO)

17/ C l i f t o n , Paul, Personal Communication from information compiled S t a t e of C a l i f o r n i a , 196!+.

18/ Tudor, W. J . , Tsunami Damage a t Kodiak, A l a s k a and Crescent C i t y ^ C a l i f o r n i a , From Alaskan Earthquake o f 27 March 1964, U.S. N a v a l C i v i l Engineering Laboratory, Port Hueneme, C a l i f o r n i a , T e c h n i c a l Note N-622, November 1964.

1^/ Raudio, V i c t o r J . , P o s s i b l e Causes of Itousually High Tsunamis a t

Crescent City, C a l i f o r n i a , U.S. Naval Postgraduate School, M o n t e r e y ' C a l i f o r n i a , I965.

20/ C r e i s l e r , Joe, T i d a l Wave Creates S a n i t a t i o n Problems, P u b l i c Vor^S-' Volume 95 No. 12, page 68-70, 138.

21/ Roberts, James A., and Kauper, Erwlnk, The E f f e c t s of Wind and P r e c i p i t a t i o n on the Modification of South Beach, Crescent C i t y , C a l i f o r n i a , i n c l u d i n g an Appendix on the Focusing of Tsunami E n e I " S y a t Crescent C i t y .

2 2 / Young, Rosemary S., Crescent C i t y D i s a s t e r Medford, Oregon, 196k-'

23/ G r i f f i n Wallace, Dark D i s a s t e r , Crescent C i t y , C a l i f o r n i a , 1964. 24/ Wiegel, Robert L., P r o t e c t i o n of Crescent C i t y , C a l i f o r n i a , from.

Tsunami Waves, Berkeley, C a l i f o r n i a , March I 9 6 5 .

25/ Magoon, 0. T., The Tsunami of May i960 as i t Affected the N o r t h e a r i ^ C a l i f o r n i a , ASCE Hydraulics D i v i s i o n Conference, Davis, C a l l f o m J - * ^ ' August 1962.

26/ Foley, Robert E., T i d a l Waves, Shcre and Beach, V o l . 32, No. 1, -27/ Stanley, A l b e r t A., Sea Wave, Shore and Beach, V o l . 32, No. 1, P

6 2 C O A S T A L E N G I N E E R I N G T Y P I C A L S E C T I O N S S A N T A CRUZ H A R B O R NO s c* L 6 C A L I F O R N I A T S U N A M I HIGH W A T E R M A R K S M A R C H 1 9 6 4 Figure 3

S T R U C T U R A L D A M A G E 63