Large-scale mapping of submarine
geohazard-related features:
Consiglio Nazionale
example from the Italian Project MAGIC
delle Ricerche
(Marine Geohazards along the Italian Coasts)
D. Ridente*, A. Bosman*, D. Casalbore*, A. Sposato*, F. L. Chiocci°*
*Istituto di Geologia Ambientale e Geoingegneria (IGAG-CNR), Roma
°Sapienza Università
Università di Roma
Outline
- structure of the project and topics
- geohazards along the italian coasts
- problems/solutions in regional
geohazard mapping based on multibeam
- examples
- concluding remarks
EGU General Assembly, 2-7 May 2010, Vienna
Structure of the project and topics
www.magicproject.it
Multibeam mapping (1:50.000)
of the Italian margins
5-year Duration:
December 2007-December 2012
Funded by the Italian Civil
Protection Department (DPC)
Scope of the Project:
provide DPC a basic tool for monitoring
and managing marine geohazards and risk
- MAGIC relies on scientific issues but…
- is not aimed at resolving scientific issues
Structure of the project and topics
Project Partners
Consiglio
Consiglio Nazionale delle Ricerche (CNR):
CNR):
- Istituto per la Geologia Ambientale e
Geoingegneria (IGAG)
IGAG) - Roma
- Istituto per le Scienze Marine (ISMAR
)-Bolo
Bologna
gna
(ISMAR)- Istituto per l’Ambiente Marino e Costiero
(IAMC)
IAMC) - Napoli
Napoli
CoNISMa (Consorzio Nazionale Interuniversitario
per le Scienze del Mare
Mare):
- University
University of Genova
- University of Trieste
- University of Rome Sapienza
- University of Palermo
- University of Cagliari
- University of Sassari
- University of Milano - Bicocca
- University of Benevento
Istituto Nazionale di Oceanografia e
Geofisica Sperimentale (OGS)
OGS) - Trieste
Main Contractor and Coordination:
CNR-IGAG,
CNR-IGAG, Rome
Structure of the project
Structure of the project and topics
72 Sheets (1:50.000) of the
“Map of Geohazard Features
of the Italian Seas”
Seas”
More than 60 k nautical miles of
MB data to be acquired during 3
yrs of ship working days
Interpretation and mapping is
based on MB morphobathymetry
MAGIC - MArine Geohazards along the Italian Coasts
www.magicproject.it
geologic processes
volcanic activity
and earthquakes
geohazard features
fault/fold-related
morphology
rapid sediment
accumulation
migrating
bedforms
slope erosion
steep slopes,
submarine
canyons
fluid escape
and venting
insitu deformation,
mud volcanoes
sediment mass
transport/failure
landslide
headscarps
and deposits
Marine Geohazards along the Italian Coasts
Tyrrhenian basin and Sicily
Channel:
Volcanic activity
Ionian and South Adriatic:
Fault systems related with
tectonic deformation and
seismicity on land
All margins:
Canyon incision and sediment
instability
seismicity
Marine Geohazards along the Italian Coasts
Interpretation and mapping is
based on MB morphobathymetry
Variety of settings:
A = retro-arc basin
B = passive margin
C = accretionary prism
any given geomorphic type may display
significant differences that challange
fulfilling cartographic criteria and codes
Problems and Solutions in geohazard mapping based on
Multibeam morpho-bathymetry
Problems:
recognition and representation of geohazard-related features and
geological processes relying mainly on MB morpho-bathymetry
Establish objective criteria for homogeneous interpretation/representation
of morphobathymetric features yielding geohazard potential
Solutions:
Separate morphological (objective) and genetic (interpretative) aspects
(mapping of morphological features independently of their nature and
geohazard potential)
1 - Define all mappable morphological features
2 - Define codes for representing morphological features independently
from their nature and related genetic processes
3 - Hierarchy of interpretative and representative scales and levels for
expressing morphological and genetical aspects of geohazard related
features: Multi-level (4 Levels) Map
1 - Define all mappable morphological features
Seafloor morphology is defined through the definition of basic features
referred to as Morphobathymetric Elements (ME)
ME are mapped at scale 1:50.000 (lower limit: 100 m) and constitute the
basic level of information relative to geohazard-related features/processes
ME are reconducted to 4 main Types:
1 - Morphological breaks or scarps
2 - Bed forms
3 - Event deposits
4 - Irregular and deformed seafloor
2 - Define codes for representing each morphological feature and
(if possible) its nature and related genetic processes
Individual Morphobathymetric Elements (ME) are represented by a graphic
symbol (line patterns and ichons) and a colour
ME of the same TYPE (e.g. scarps) are imaged by the same graphic symbol
but of different colour depending on genesis and processes
(e.g. tectonics, sediment failure, canyon incision, unknown, etc.)
3 - Hierarchy of interpretative and representative scales and levels
for expressing morphological and genetical aspects of
geohazard-related features: Multi-level (4 Levels) Map
At a regional scale, Physiographic Domains (PD
(PD)) include the continental shelf,
seamounts, volcanic apparatus, etc., and represent Level 1 (scale 1:250.000)
The envelope of broad (sub-regional) areas including a characterizing assemblage of
ME is termed Morphological Unit (MU
(MU)) and is mapped as at scale 1:50.000 (using a
distinctive transparent color)
color) as Level 2
Morphobathymetric Elements (ME
(ME)) are the basic geological information mapped at
scale 1:50.000 as representative Level 3
Critical Zones (CZ
(CZ)) are near-coast features (e.g.
canyon heads) with high risk potential and are
evidenced with a red rectangle and described in detail
using all available data: Level 4
some examples….
In addition:
- Descriptive Notes
(Level 3 and 4)
- Morpho-parametric
Catalogue (Level 2)
- Infor.Mare
Infor.Mare bibliographic
database
Level 3 (ME)
Sheet 33 - Catania
Level 3 (ME)
Legend
1: canyon headscarp; 2: slide scarp; 3: intra-channel slide
scarp; 4: erosion by unknown process (e.g. by “normal”
erosion or mass failure); 5: channel-flank scarp and
terrace; 6: scarp of unknown origin (e.g. either by erosion,
mass failure or tectonics); 7: base of canyon scarp; 8:
secondary channel (rim and base of scarp not traceable);
9: gully; 10: lava flow.
Red box labelled CZ1_F33 indicates a Critical Zone
(Level 4) where a canyon headscarp deeply indents the
shelf and the coastline.
Sheet 33 - Catania
Level 1 (PD)
Intraslope and bathial basin
Intraslope seamount/relief
Volcanic apparatus
Level 2 (MU)
Concluding Remarks
MAGIC Project (MArine Geohazard along the Italian Coasts)
Map of Geohazard-related features of the Italian seas based on
morpho-bathymetric (Multibeam) data
Evidence of geological features/processes and related “danger”
Basic tool for Monitoring and Managing Geohazard
Define site-specific marine geohazard and potential risk
Integrating MB data with all other geological information