MASS MOVEMENT FEATURES ALONG THE CENTRAL CALIFORNIA
MARGIN AND THEIR MODELED CONSEQUENCES FOR TSUNAMI
GENERATION
H. G. GREENE
Monterey Bay Aquarium Research Institute & Moss Landing Marine Laboratories,
Moss Landing, CA USA
S. N. WARD
Institute of Geophysics and Planetary Physics, University of California, Santa Cruz, CA
USA
Abstract
Many mass movement features have been mapped in the Monterey Bay region of
central California. Most of these features have the appearance of being displaced by
fluid flow. Therefore, fluids may have played a major role in facilitating mass
movement along this tectonically active continental margin and will do so in the future.
We selected three major areas of mass movement located within submarine canyons and
modeled their potential to generate tsunamis. Run-up extent is dependent upon slump
geometry, depth and size, and we believe that two could have produced tsunamis. The
third area exhibits multiple retrogressive failures and future tsunami occurrences appear
feasible.
Keywords: Submarine slide, mass movement, tsunamis, fluid flow, submarine canyons
1. Introduction
As more seafloor of the California offshore is imaged with high-resolution multibeam
bathymetric technology, more areas of mass movement are discovered. Many of these
areas lie adjacent to, or within, areas that contain hydrocarbon reservoirs at depth, or
may be in areas where extension of on land aquifers crop out on or near the sea floor.
Multibeam bathymetric data collected in the Santa Barbara Channel by the Monterey
Bay Aquarium Research Institute (MBARI) show substantial mass wasting occurring
along the northern slope of the Santa Barbara Basin, immediately adjacent to faults and
folds that trap hydrocarbons associated with the offshore Santa Maria petroleum
province (Greene, 1976, Eichhubl et al., 2002, Greene et al., 2002). Similar types of data
collected by the U.S. Geological Survey offshore of Long Beach, California (Bohannon
and Gardner, 2001) show a large debris avalanche that lies near an area where onshore
aquifers crop out at the shelf break (Vedder, 1987) and adjacent to hydrocarbon
containing structures such as those within the Inglewood Trend and those near the Beta
oil field (Parker, 1971; Vedder, 1987).
In the Monterey Bay region of central California, a large multibeam bathymetric data set
collected by MBARI shows a region of extensive mass movement (Greene et al., 2002).
Slumps, debris flows and other submarine landslides are concentrated along canyon
walls and the lower continental slope (Fig. 1). Based primarily on geomorphology,
Greene et al. (2002) suggest a Quaternary age for most of the landslides imaged in the
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area. However, many slides appear younger, and some occurred within historic time.
For example, a small landslide occurred at the head of Monterey Canyon during the
1989 Loma Prieta Earthquake (M6.9) with a small (~0.5 m high) tsunami reported to
have entered the Moss Landing Harbor and a turbidity current reported to have traveled
down the canyon axis (Greene and Hicks 1990; Schwing et al., 1990; Garfield et al.,
1994). In addition, many distinct and youthful slumps occur at the base of the headward
walls of Monterey Canyon, which appear to result from undercutting of the walls during
debris flow or turbidity current events. (Greene et al., 2002).
The upper continental slope north of Monterey Bay is heavily incised with submarine
canyons and gullies (Greene and Hicks, 1990; Greene et al., 2002). Here the canyon
heads of Ascension and Año Nuevo submarine canyons are collapsed and many rills,
thin sediment flows and slumps exist, which are interpreted to have originated from
fluid flow (Greene et al., 1999, 2002). These features are concentrated along shelf-edge
faults that cut deeply into the Outer Santa Cruz Basin, a hydrocarbon reservoir that
appears to be leaking along structures associated with petroleum traps (Mullins and
Nagel, 1982; Nagel et al., 1986; Greene, 1990; Greene et al., 2002).
Large mass movement features in the Monterey Bay region suggest that a potential for
tsunami generation exists. Our intent is to model some of the larger features to
determine if tsunamis could have occurred in the past.
From many mapped features of mass movement in the Monterey Bay region we have
selected two distinct landslides of past movement and one potential landslide to model
tsunamis generation using models after Ward (2000, 2001). Simrad EM 300, 30 kHz
multibeam bathymetric data collected by MBARI in 1997 were used to image and
model the landslide sites indicated in figure 1.
1.1 PHYSIOGRAPHY AND TECTONIC SETTING
The Monterey Bay is located along the central California coast approximately 180 km
south of San Francisco (Fig. 1). The offshore Monterey Bay region extends from Point
Año Nuevo in the north to Point Sur in the south and is dominated by the AscensionMonterey Canyon system. This system is comprised of Ascension, Año Nuevo, and
Cabrillo canyons of the Ascension Canyon sub-system and Soquel, Monterey, and
Carmel canyons of the Monterey Canyon sub-system (Greene and Hicks, 1990). The
submarine canyons of the Ascension Canyon sub-system are relatively straight in
contrast to Monterey Canyon, which is quite sinuous with many meanders (Fig. 1;
Greene et al., 2002).
The Monterey Bay region lies within an active tectonic transform boundary, within and
adjacent to the right-lateral strike-slip San Andreas Fault system that separates the
Pacific Plate from the North American Plate. Slight oblique convergence and slip along
this fault system produces both strike-slip and thrust earthquake movement (Cockerham
et al., 1990). In the offshore, dextral transcurrent movement is displayed by faults within
the Palo Colorado-San Gregorio and Monterey Bay fault zones (Fig. 1).
The Palo Colorado-San Gregorio fault zone cuts through the middle part of the
Monterey Canyon, controls the morphology of Carmel Canyon, and offsets the heads of
Tsunami Generation in Central California
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the Ascension Canyon sub-system (Greene et al., 1999). The zone is seismically active
with past recorded earthquakes offshore ranging from minor (>2 M) to moderate (6.4
M) that occurred as recently as 1926 (Richter, 1958; Coppersmith and Griggs, 1978;
Gawthrop, 1978; Begnaud et al., 2000). An estimated ML of >7.3 has been calculated to
be possible along this fault zone based on its length and past history (Petersen et al.,
1996; Clark et al., 1999).
Figure 1. MBARI EM 300 multibeam bathymetric image of the Monterey Bay area showing the submarine
canyon systems and areas of mass wasting. This figure also shows the locations of faults and submarine
slumps. Modified after Greene et al., 2002 and Wagner et al., 2002.
The Monterey Bay Fault Zone, comprised of many en-echelon faults, extends offshore
in a northwest direction from the city of Monterey to merge with the Palo Colorado San
Gregorio fault zone just west of Santa Cruz (Fig. 2; Greene, 1977, 1990; Wagner et al.,
2002). Three major thoroughgoing faults, Navy, Chupinas, and Seaside faults, are
responsible for the formation of the Monterey Meander in Monterey Canyon and are
well mapped onshore (Clarke et al., 1999; Greene 2002; Wagner et al., 2002). Minor
(>2M) to moderate (6.1M) earthquakes have been reported for this fault zone (Greene,
1990; Begnaud et al., 2000) and a predicted potential of >6.0 ML is possible.
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2. Palaeo-landslides: Variety, Size, Apparent Age, and Distribution
Extensive mass wasting, including large mass movement features or landslides, mark
the walls of the Ascension-Monterey Canyon system and continental slope of the
Monterey Bay region (Fig. 1; Greene and Hicks, 1990; Greene et al., 2002). Within the
submarine canyons over 470 km2 of combined area has been subjected to mass
movement in the past. A variety of mass movement features exist, including rotational
slumps, debris flows, thin sediment flows, and excavation scars and scarps that delineate
many of the landslides mapped in the region (Greene et al., 2002). Sizes of these
features along the California continental margin range from small (on the order of 1km2
in area) like that on the upper slope region, northwest of Ascension Canyon, to very
large (the size of Monterey Bay in area and >35km3 in volume; Gutmacher and
Normark, 1993) on the lower Sur slope (Sur Slide). In addition, these landslides appear
to range from mature (i.e. younger sediments overlapping mass movement features)
geomorphic ages to youthful, yet no dates of movement have been determined. It is
suspected that much landslide activity took place during the last low-stand of sea level
in the Pleistocene (ca. 18 Ka), yet this has not been thoroughly documented (Normark
and Gutmacher, 1988; Greene et al., 2002). However, newly forming propagating head
scarps adjacent to older landslide scars on the upper canyon wall in the Monterey
Meander of Monterey Canyon, may indicate a site of incipient mass movement,
particularly of retrogressive slumps within the Monterey Bay fault zone. In addition,
slumps along the outside bends of the canyon’s axial meanders, near the base of the
canyon head walls (Fig.1), may continue to move, perhaps suddenly.
Figure 2. Illustration of tsunami generation by landslide material moving on the sea floor. The long duration
of landslide sources make complex waves that can strongly concentrate in the direction of slide motion.
Tsunami Generation in Central California
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3. Landslide Tsunamis Excitation
Geology clearly shows that submarine landslides have occurred in Monterey Bay. What
magnitude of tsunami hazard do these landslides pose to nearby coasts? To help address
this question, we employ classical linear water wave theory and model landslide sources
as equivalent vertical displacements of the sea floor. In a uniform ocean of depth h, a
bot
vertical bottom disturbance u z (r0 ,t) evokes vector tsunami waveforms at observation
point r=x xˆ +y yˆ , depth z, and time t of Komen et al. (1994), Dingemans (1997), Ward
(2000, 2002).
(1a)
u(x, y, z, t ) = Re ∫ dk
e i( k•r − ω(k)t)
4π 2 cosh(kh)
 sinh( k(h - z)) ˆ cosh(k(h - z)) 
× zˆ
− ik
F(k, t)
sinh( kh)
sinh(kh) 

k
ik •r  
cosh(k(h - z)) 
e
sinh( k(h - z))  ˆ 
+ ∫ dk
 − ik sinh( k(h - z)) −
G(k, t)
ˆz cosh( k(h - z)) −
2



tanh(kh) 
tanh(kh)
4π 
k
(1b)
t
iω ( k)t 0
F(k , t) = ∫ dr0 e −ik •r0 ∫ dt 0 u bot
z (r0 , t 0 ) e
0
where
r0
G(k , t) = ∫ dr0 e −ik •r0 u bot
z (r0 , t )
r0
In equations 1a,b, wavenumber k=|k|, frequency ω(k) = gk tanh(kh) , r0=x0 xˆ +y0 yˆ ,
2
kˆ =kx xˆ +ky yˆ , dk=dkxdky, dr0=dx0dy0, and g=9.8 m/s . The tsunami theory above is
fully three-dimensional, depth-dependent and not restricted to long or short waves. The
bot
displacement function u z (r0 ,t) can take any shape, thickness, slide velocity, slide
direction and time history. Most of these landslide parameters will be constrained from
geological information, others from simple kinematic models. Figure 2 illustrates how
seafloor slides make tsunami waves. For this figure, we evaluate (1a) and (1b) for a 10
m thick, 2 km wide block that slides for 6 km. The block starts at zero velocity,
accelerates to 49 m/s then slows to a stop on a flat surface 500 m below sea level. As the
slide moves, water near the ocean bottom shoves up and over the front of the block, then
falls back down behind. This up-and-down dipole motion transmits to the surface, but in
a low passed form in wavelength by the ocean layer. The cosh(kh) in (1a) does the
filtering job. At each instant, a new dipole forms as the block moves. Simultaneously,
older dipoles propagate away and disperse. Depending on the water depth and variable
slide speed, the new dipoles add constructively in phase to the surface waves
sometimes, and sometimes not. By the time the block stops, tsunami waves often run
almost completely in the slide direction and do not resemble dipole-generated fields.
Real landslides of course occur on a slope, but the tsunami generation process is not
significantly different.
Greene and Ward
348
The second integral in equation 1a vanishes at the surface and does not propagate away
from the source. It contributes to the mechanism of figure 2, but usually the term is of
little interest. Another way to write the propagating part of equation (2) is:
(2)
sinh(k(h - z)) 
ˆ
zJ 0 (k r − r0 )


sinh(kh)
k dk
×

d
u( x, y, z, t ) = ∫
r
0
∫
cosh(
k(h
z))
2
cosh(
kh)
π


0
r0
ˆ
+ RJ 1 (k r − r0 ) sinh( kh) 


∞
t
∫ dt
0
u bot
z (r0 , t 0 ) cos[ω ( k)(t − t 0 )]
0
ˆ =(r-r )/|r-r | and the J are cylindrical Bessel functions.
R
0
0
n
Generalisation of equation (2) to a non-uniform depth ocean entails the calculation of
a ray-path specific travel time T(ω,r,r0), and the incorporation of new geometrical
spreading and shoaling factors G(r,r0) and SL(ω,r,r0) (Ward, 2001). At the sea surface
(z=0), the vertical component of tsunami motion simplifies to
(3)
∞
dr0 k 0 (ω ) J 0 (ωT(ω , r, r0 ))
×
2πu 0 (ω )cosh[k 0 (ω )h(r0 )]
r0
u surf
z (r , t ) = ∫ dω ∫
0
t
G(r, r0 )S L (ω , r, r0 ) ∫ dt 0 u bot
z (r0 , t 0 ) cos[ω (t − t 0 )]
0
The integration variable in equation (3) changes from wave number to frequency
because the latter is conserved as waves traverse water of varying depth. The k0(ω) and
u0(ω) are wave number and group velocity now specific to water of depth h(r0) over the
landslide.
3.1 TSUNAMI ENERGY
Linear tsunami theory provides a convenient estimate of total wave energy (ET(t)) at any
time as shown in equation (4):
(4)
surf
E T (t) = (1/ 2)ρ wg ∫ dA(r)[E z (r,t)]
2
r
surf
with E z (r,t) being the tsunami envelope as shown in equation (5):
(5)
surf
{ surf
2
surf
E z (r,t) = [u z ( r, t)] +[H z
}
2 1/ 2
(r,t)]
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which has units of meters and incorporates both the vertical tsunami field and its Hilbert
surf
Transform. We compute H z (r,t) by replacing cosωt by sinωt in (3).
3.2 LANDSLIDE ENERGY
Undersea landslides release gravitational potential energy in the amount (6):
(6)
E L = (ρs − ρw )g ∫ dA( r)∆u(r)h(r)
r
Here, h is water depth, ρs is the density of the slide material, and ∆u is its excavation or
deposition thickness. Excavation is negative and the integral covers all sea floor where
∆u(r)≠0. EL fixes the energy budget of all landslide processes. The energy of radiated
tsunami and all manner of frictional losses draw from this pool (Actually, the tsunami
waves generated during landslides can be considered a frictional loss.) EL depends only
on the initial and final state of the slide, whereas ET depends on its entire kinematic
history. The ratio ET/EL quantifies a slide’s tsunami generation efficiency.
4. Selected Landslides for Tsunami Modeling
From the many landslides mapped in the central California region we modeled youthful
looking features that appear to have failed recently and features that appear to have a
potential for failure in the future. In addition, we selected those landslides that are
shallow and close to shore (submarine canyon failures) rather than distant and deep
failures. We also selected slumps and block avalanches rather than debris and thin
sediment flows, as these features remain intact during displacement.
4.1 ASCENSION CANYON LANDSLIDE
Ascension Canyon landslide, an apparent slump block, is located in the upper part of
Ascension canyon at a depth of ~600 m and is 1.5 km long, 370 m wide, and ~50 m
thick (Fig. 3). This feature is anomalous as it is a flat-topped block that projects into,
and constricts, a fairly straight canyon eroded into flat-lying marine Pliocene sandstones
and mudstones of the Purisima Formation on the continental shelf north of Monterey
Bay (Greene, et al., 2002). It is comprised of a steep (~40°), high (215 m) head scar, a
primary and one secondary slump block and a steep near vertical toe 160 m high that
extends into the canyon axis at a depth of 800 m. This slump appears to have dropped
down some 300 m (from 300 m to 600 m water depth) into the axis of the canyon
moving 2.4 x 107 m3 of material for 1.5 km (run-out) in a southerly direction. The total
area of the slump is 4.9 x 105 km2, with an excavation area of 9.58 km2. The cause of
the slump is unknown, although it lies in an area that may have experienced active fluid
flow in the past.
This slump has the mass to displace water in one rapid motion, but our modeling shows
that it is too deep and oriented in the wrong direction to produce a tsunami of any
significance. The major energy of the resultant tsunamis is directed toward the
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Greene and Ward
Monterey Peninsula some 45 km southeast of the failed wall (Fig. 4). Although our
model indicates that a 2 m negative tsunami wave is initially generated, the closest
landfall is directly east along the high (~10 m high) cliffs of the coast near Davenport
where a 1 m high tsunami is calculated to have run-up 2.98 m, well below the crest of
the cliffs. The Monterey Peninsula is estimated to have had a 0.52 m run-up and the
sites at Santa Cruz and Moss Landing would have only seen a 1.34 m and 0.36 m run-up
(Fig. 4). In Figures 4, 5, and 7 darker shading represents positive waves (crests) while
light shading represents negative waves (troughs). Numbers in Figures 4 and 5 represent
highs and lows (-) in meters at dots.
Figure 3. Expanded view of Ascension Canyon slump from MBARI EM 300 multibeam bathymetric data.
4.2 TUBEWORM SLUMP (LOWER MONTEREY CANYON)
Tubeworm slump, named as such because of the high concentration of Vestimentiferan
tube worms located along its head scarp, is a large 2 km long by 2 km wide triangularlike excavation scar (Fig. 5) that apparently resulted from the removal of ~1.03 x 108 m3
of material that slid to the south into the axis of Monterey Canyon. No surface evidence
of the landslide deposit is seen in the canyon axis and we assume it was either buried
under canyon axis sediment or transported down the canyon away from the foot of the
landslide scar. Therefore, we assume that the landslide material ran out to the south for
3.4 km crossing the entire width of the canyon and coming to rest along its southern
wall, before being buried or transported down canyon.
Tubeworm Slump has a classic landslide scar with an arcuate ~40° steep head scar and a
175m wide head block that can be seen at the base of the head wall. Based on previous
geologic mapping in this area (Greene, 1977; Greene and Hicks, 1990) the slip plane or
sole of the landslide appears to be the top of the Miocene Monterey Formation, a highly
Tsunami Generation in Central California
351
fractured, hydrocarbon-rich, diatomaceous mudstone and chert unit, and the material
that failed was primarily Pliocene marine sedimentary deposits (sandstones and
mudstones) equivalent to the Purisima Formation. The slip plane was possibly
lubricated by fluids migrating through the Monterey Formation.
Figure 4. Ascension tsunami (left) tsunami envelope (right). Less than 0.5% of landslide energy went into this
tsunami. Note bright spot near shore. These are the waves shoaling in shallow water.
Our model showed that at four minutes after the failure, the calculated geometry of the
tsunami was circular with the largest and strongest waves focused to the south and the
next stronger field focused to the north (Fig. 5). Approximately eight minutes after the
failure event the tsunamis would have reached the Monterey Peninsula with a 1 m high
positive wave. A short time after eight minutes the first arrival waves at Santa Cruz
would have occurred with a 2 m negative trough, resulting in a withdrawal of water at
the shoreline followed by a positive wave or inundation.
4.3 MONTEREY MEANDER MASS MOVEMENT FIELD
A large (>90 km2 area) mass movement field exists at the apex of the Monterey
Meander and is composed of many retrogressive slumps and debris flows (Greene et al.,
2002). This field lies within the Monterey Bay fault zone that is seismically active
(Greene and Hicks, 1990). A distinct rugged head wall over 100 m in height and varying
in slope from 14° to 27° characterises the head of the field (Fig.6). In many places along
the upper part of the head wall the morphology is scalloped denoting the past
occurrences of small landslides. The entire head scar area is composed of regionally
flat-lying Pliocene Purisima Formation sandstones and mudstones (Greene, 1977;
Greene et al., 2002). In many places this formation is deformed (fractured and folded to
near vertical dips) from fault motion, and observations made from ROV dives show a
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Greene and Ward
rubble slope resulting from active headwall failures. This and the general morphology of
the head scarp indicate that many small wall failures have occurred in this area.
Although the suspected cause of mass wasting here is fault rupture and earthquakes,
because the field lies within the seismically active Monterey Bay fault zone, we also
suspect fluid flow may play a role, as fluid flow along structure (faults) and stratigraphy
(bedding planes) in this area is evidenced by concentrations of chemosynthetic
communities and bacterial mats (Greene et al., 1999).
Figure 5. Expanded view of Tubeworm slump from MBARI EM 300 multibeam bathymetric data and
tsunami modeling. Positive areas shown in dark shading, negative in light shading. Numbers represent
height or depressions (-) in meters at dots.
From our model, the geometry of the generated wave is elliptical with the largest and
strongest waves being focused to the south, toward the Monterey Peninsula (Fig. 7).
Approximately eight minutes after the failure event the tsunami would reach the
Monterey Peninsula with a positive 5 m (high) wave approaching Monterey Harbor and
a positive 7 m (high) wave at Moss Landing, resulting in inundation at both places. A
short time after 8 minutes the first arrival waves of negative 1 m would arrive at Santa
Cruz resulting in a withdrawal of water at the shoreline followed by a positive wave or
inundation.
Tsunami Generation in Central California
353
Figure 6. Expanded view of Monterey Meander mass wasting field showing possible incipient head scars
from MBARI EM 300 multibeam bathymetric data. See Figure 1 for location.
5. Conclusions
Although there are no reports of locally generated tsunamis in the Monterey Bay region,
the extensive amount of mass wasting imaged in the Ascension-Monterey Canyon
system suggests that locally derived tsunamis may have occurred in the past and could
occur in the future. Many of these failures could be the result of fluid flow and may not
need earthquakes or other stimulants to initiate failure. Continued fluid flow and canyon
wall undercutting could initiate non-seismogenic tsunamis in the future.
We modeled three different types (present and past) of submarine landslides to
determine size and run-up that may occur if the features failed rapidly (instantaneously)
and remained intact during most of the run-out. Two of the landslides, Ascension
Canyon and Tubeworm slump, occurred sometime in the recent past (within the late
Quaternary or historically) as their morphologies appear youthful. The incipient
Monterey Meander failure lies in a seismically active area, cut by faults (Navy and
Seaside faults) of the Monterey Bay Fault Zone, and has experienced extensive failures
in the past. Based on estimated dimensions and volume of the incipient landslide we
calculated the generation of a substantial tsunami (11m high in Monterey area, and 8m
high at Moss Landing, and 2m high at Santa Cruz; Fig. 7) if a large failure took place at
this locality instantaneously.
A significant conclusion is that even though some landslides (i.e., Ascension Canyon
landslide) appear large enough to produce a tsunami of notable size, depth of water and
orientation play a major role in developing a critical size event. Our calculations
indicate that although all of the past failures we modeled had the potential to produce a
sizable tsunami, many were oriented in a direction that would allow substantial
attenuation of energy before reaching land, and thus have little run-up impact. More
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work needs to be done in order to determine which of the landslides mapped in central
California could have produced a tsunami, what areas may have potential tsunami
generation, and to determine failure mechanisms. We suspect that many mapped
landslides in the central California offshore can be categorised into geology, geometry,
depth and distance from land for the purpose of accurately establishing tsunami prone
zones.
Figure 7. Monterey Meander tsunami. Note strong focusing of waves in the direction of slide motion
6. Acknowledgements
This work was partially funded by the David and Lucile Packard Foundation. We wish
to thank Lee Murai and Holly Lopez for their assistance in preparing the figures and
calculating the areas of volumes used in the modeling, Dr Ivano Aiello and Dr. Tracy
Vallier for generously giving up their time and agreeing to review the paper at short
notice.
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7. References
Begnaud, M.L., McNally, K.C., Stakes, D.S., and Gallardo, V.A., 2000. A crustal velocity model for locating
earthquakes in Monterey Bay, California . Bull. Seismological Society of America, 90(6):13911408.
Bohannon, R.G. and Gardner, J.V. 2001. Submarine landslides at San Pedro Sea Valley, southwest Los
Angeles Basin. In Watts, P. (Ed.), Proceedings of the workshop on the prediction of underwater
landslide and slump occurrence and tsunami hazards of Southern California, Los Angeles, 10-11
March, 2000. In press, Marine Geology.
Clark, J.C., Weber, G.E., Rosenberg, L.I., Bunham, K., 1999. Neotectonics of the San Gregorio Fault Zone,
central coastal California. In: Garrison, R.E., Aiello, I.W., Moore, C.J. (Eds.), Late Cenozoic
Fluid Seeps and Tectonics Along the San Gregorio Fault zone in the Monterey Bay Region,
California. Pacific Section, American Association of Petroleum Geologists Volume and Guidebook,
GB-76, Bakersfield, 119-156.
Cockerham, R.S., McCullock, D.S., and Greene, H.G., 1990. Earthquake epicenters and selected fault plane
solutions of the central California continental margin, in Greene, H.G. and Kennedy, M.P., (Eds.),
California Continental Margins Geologic Map Series, Area 5 of 7, Central California Continental
Margin, Sheet 2 of 4, Map No. 5B. California Division of Mines and Geology, Scale 1:250,000.
Coppersmith, K.J., and Griggs, G.B., 1978. Morphology, recent activity and seismicity of the San Gregorio
fault zone. In Silver, E.A. and Normark, W.R., (Eds)., San Gregorio-Hosgri fault zone, California.
California Division of Mines and Geology, Special Report 137: 33-43.
Dingemans, M.W., 1997. Water wave propagation over uneven bottoms, Part-1 linear wave propagation.
World Scientific, Singapore.
Eichhubl, P., Greene, H.G. and Maher, N. 2002. Physiography of an active transpressive margin basin: highresolution bathymetry of the Santa Barbara basin, Southern California continental borderland.
Marine Geology 184 95-120.
Garfield, N., Rago, T.A., Schnebele, K.J., and Collins, C.A., 1994. Evidence of a Turbidity Current in
Monterey submarine canyon associated with the 1989 Loma Prieta earthquake. Continental Shelf
Research, 14 (6): 673-686.
Gawthrop, W.H., 1978. Seismicity and tectonics of the central California coastal region. In Silver, E.A. and
Normark, W.R., (Eds)., San Gregorio-Hosgri fault zone, California. California Division of Mines
and Geology, Special Report 137: 45-65.
Greene, 1970. Geology of the southern Monterey Bay and its relationship to the ground water basin and saltwater intrusion. U.S. Geological Survey Open-File Report, 50p.
Greene, 1976. Late Cenozoic geology of the Ventura Basin, California. In: Howell, D.G. (Ed.) Aspects of the
geologic history of the California continental borderland. Misc. publ. 24, American Association of
Petroleum Geologists, Pacific Section, Bakersfield, CA.. 499-529.
Greene, H.G., 1977. Geology of the Monterey Bay region. U.S. Geological Survey Open-File Report, 50p.
Greene, H.G., 1990. Regional tectonics and structural evolution of the Monterey Bay region, central
California. In: Garrison, R.E., Greene, H.G., Hicks, K.R.,Weber, G.E., and Wright, T.L. (Eds.),
Geology and tectonics of the Central California coastal region, San Francisco to Monterey, Pacific
Section, American Association of Petroleum Geologists Volume and Guidebook, GB 67,
Bakersfield, 31-56.
Greene, H.G., Hicks, K.R., 1990. Ascension-Monterey canyon system: history and development. In: Garrison,
R.E., Greene, H.G., Hicks, K.R., Weber, G.E., Wright, T.L. (Eds.), Geology and tectonics of the
central California coastal region, San Francisco to Monterey. American Association of Petroleum
Geologists, Pacific Section, Volume and Guidebook, GB 67, Bakersfield, 229-250.
Greene, H.G., Maher, N., Haehr, T.H., Orange, D.L., 1999. Fluid flow in the offshore Monterey Bay region.
In: Garrison, R.E, Aiello, I.W., Moore, C.E., (Eds.), Late Cenozoic fluid seeps and tectonics along
the San Gregorio Fault Zone in the Monterey Bay region, California. Pacific Section, American
Association of Petroleum Geologists Volume and Guidebook, GB-76, Bakersfield, 1- 19.
Greene, H.G., Maher, N.M. and Paull, C.K., 2000. Landslide hazard off Santa Barbara, California. EOS
Transactions, American Geophysical Union, 81:F750.
Greene, H. G., Maher, N.M., and Paull, D.K., 2002. Physiography of the Monterey Bay National Marine
Sanctuary and implications about continental margin development. Marine Geology, 181: 55-82.
Gutmacher, C.E., Normark, W.R., 1993. Sur submarine landslide, a deep-water sediment slope failure. In:
Schwab, W.C., Lee, H.J., Twichell, D.C. (Eds.), Submarine landslides: selected studies in the U.S.
Exclusive Economic Zone. U. S. Geological Survey Bulletin 2002: 158-166.
Komen, G.J., Cavaleri, M. Donelan, Hasselmann, K., Hasselman, S., and Janssen, P.A.E.M., 1994. Dynamics
and modeling of ocean waves. Cambridge University Press.
356
Greene and Ward
Mullins, H.T. and Nagel, D.K., 1982. Evidence of shallow hydrocarbons offshore, northern Santa Cruz
County, California. Bull., Amer. Assoc. Petroleum Geologists, 66: 1130-1140.
Nagel, D.K., Mullins, H.T. and Greene, H.G. 1986. Ascension submarine canyon, California – Evolution of a
multi-head canyon system along a strike-slip continental margin. Marine Geology, 73:285-310.
Normark, W.R., Gutmacher, C.E., 1988. Sur submarine slide, Monterey Fan, central California.
Sedimentology, 35: 629-647.
Parker, F.S., 1971. Petroleum potential of southern California offshore. In Cram, I.H., ed., Future petroleum
provinces of the United States – Their geology and potential. Amer. Assoc. of Petroleum
Geologists, Memoir 15, 178-191.
Petersen, M.D., Bryant, W.A., Cramer, C.H., Cao, T., Reichle, M.S., Frankel, A.D., Lienkaemper, J.J.,
McCrory, P.A., Schwartz D.P., 1996. Probabilistic seismic hazard assessment for the state of
California. California Division of Mines and Geology Open File Report 96-08 and U.S.Geological
Survey Open File Report 96-706, 33p., 2 appendices.
Richter, C.F., 1958. Elementary seismology. W.H. Freeman and Company, San Francisco, California, 768 p.
Schwing, F.B., Norton, J.G. and Pilskaln, 1990. Response of Monterey Bay to the Loma Prieta earthquake.
Amer. Geophy. Union EOS, 71(6):250-251.
Vedder, J.G., 1987. Regional geology and petroleum potential of the southern California borderland. In
Scholl, D.W., Grantz, A. and Vedder, J.G., ed., Geology and resource potential of the continental
margin of western North America and adjacent ocean basins – Beaufort Sea to Baja California.
Circum-Pacific Council for Energy and Mineral Resources (Amer. Assoc. Petroleum Geologists),
Earth Science Series, 6:403-447.
Wagner, D.L., Greene, H.G., Saucedo, G.J., and Pridmore, C.L., 2002. Geologic map of the Monterey 30’ x
60’ Quadrangle and adjacent areas, California: A digital database. California Geological Survey
CGS CD 2002-04.
Ward, S.N. and Asphaug, E., 2000. Asteroid Impact Tsunami: A probabilistic hazard assessment. Icarus, 145:
64-78.
Ward, S.N., 2001. Landslide tsunami. J. Geophys. Res., 106:B6, 11,201-11,216.
Ward, S.N., 2002. Tsunami. In Myers, R.A., ed., Encyclopedia of Physical Science and Technology. Academic
Press, 17: 175-191.