Table of Contents (Leighton and Associates Inc Report) 1960050-03
TABLE OF CONTENTS
Section Page
1.0 INTRODUCTION 1
2.0 GEOLOGY 3
3.0 OFFSHORE INVESTIGATIONS 9
4.0 ONSHORE INVESTIGATIONS 13
5.0 LANDSLIDE GEOMETRY 18
6.0 LANDSLIDE MOVEMENT ,1
7.0 SHORE EROSION AND DEBRIS PRODUCTION '5
8.0 FOUNDATION ANALYSIS ''7
9.0 CONCLUSIONS AND RECOMMENDATIONS 29
Figures
Figure 1 Site Location Map Rear of Text
Figure 2 Bedrock Geology Map Rear of Text
Figure 3 Landslide Index Map Rear of Text
Figure 4 1995 Topography of Portuguese Bend Landslide and
11111 Summary of Survey Monument Results Rear of Text
Figure 5 Regional Fault Map Rear of Text
Figure 6 Historical Earthquakes, 1800 to 1996 Rear of Text
Figure 7 Approximate October 1996 Ground Water Surface
Elevation Contours Rear of Text
Figure 8 Bathometry Map Off Portuguese Bend Landslide Rear of Text
Figure 9 Isopach Map of Sediment Thickness Rear of Text
Figure 10 Isopach Map of Sediment Thickness Rear of Text
Figure 11 Summary of Key Features and the 1995 Topographic Map
of the Portuguese Bend Landslide Rear of Text
Figure 12 Subslides of the Active Portuguese Bend Landslide Rear of Text
Figure 13 Cross-Section A-A' v Rear of Text
Figure 14 Cross-Section B-B' Rear of Text
Figure 15 Cross-Section C-C' Rear of Text
Figure 16 Cross-Section D-D' Rear of Text
Figure 17 Approximate Elevation Contours for Basal Rupture Surface Rear of Text
Figure 18 Shoreline Evolution Rear of Text
Figure 19 Comparison of Bottom Contour Lines Rear of Text
Figure 20 Generalized 1956 Landslide Reactivation Sequence Rear of Text
Figure 21 Landslide Displacement Rates and Annual Rainfall From
Station 44LACFCD, 1956 to 1969 Rear of Text
1960050-03
TABLE OF CONTENTS Cont'd •
Figures Cont'd
Figure 22 Displacement Rates for Monitoring Station K and
Monthly Rainfall, 1990 to 1996 Rear of Text
Figure 23 Displacement Rates for Eastern Portion of Landslide
and Annual Rainfall, 1956 to 1969 Rear of Text
Figure 24 Cumulative Landslide Material Loss Rear of Text
Figure 25 Average Yearly Loss of Material Rear of Text
Figure 26 Sample Cross-Section Showing Debris Erosion Rear of Text
Figure 27 Proposed Revetment Design Rear of Text -
Tables
Table 1 Historical Earthquakes 1800 to 1996, Magnitude 5.5 to 9.0 Rear of Text
Table 2 Deterministic Site Parameters Rear of Text
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