This document discusses applications of Comprehensive Nuclear-Test-Ban Treaty (CTBT) data and products in Comoros. It focuses on monitoring seismic and volcanic activity from Karthala volcano on Grande Comore island using the CTBT's International Monitoring System. Key points discussed include: - Karthala volcano is a major seismic and infrasound source and its eruptions in 2005 were recorded by CTBT stations. - The 2004 Indonesian tsunami caused run-ups of up to 6.9 meters in coastal areas of Comoros, as recorded by CTBT and surveys. - Comoros' National Data Centre analyzes regional seismic events using CTBT data, such as two

1. Title:
CTBT APPLICATIONS IN COMOROS
Ms. Mariama MADI
Earth Science Field, Seismic Analyst National Data Centre, Volcano Observatory Collaborator, CNDRS
(National Centre of Scientific Research and Documentation), Moroni-COMOROS
Email: mariabdjul@hotmail.com
Abstract:
Civil and scientific uses of CTBT data and products in Comoros are a reality considering natural
hazards and catastrophes related to the "Karthala" volcano activities in Comoros, which for some
years of eruptions, remain the major source of important releases of ashes and gases. The oceanic
aspect is also affected by the fact that the 2004 Indonesian Tsunami is recorded with up to 6.9
run ups in several coastal areas in Comoros.
Through the CTBT International Monitoring System, recent events (2010, 2013 etc.) were
clearly recorded.
Key words:
Seismic Source: Karthala (Active volcano), Oceanic hazards: Tsunami effects, Volcano hazards: infrasound and
Seismic effects
1. Introduction
Karthala Volcano, relevant Source of Seismic
and Infrasound hazards in the Comoro Islands.
Without any Hydro-acoustic Station in
the vicinity of Comoro-Islands, still the Hydro-
acoustic Technology shows a global Interest,
while NDCs can have access to the IDC Data
and Products.
this access allows the scientific community to
understand further the aspect of the oceanic
activities, the source, the word areas affected, as
the case during the 2004 Indonesian tsunami (up
to 6.9 m run-ups in several coastal areas in
Comoro Islands).
These following points raise the interest
of Subject
-2004 Indonesian Tsunami
-Karthala Volcano: as an Infrasound source
(Fig.1)
Corresponding Author: Ms. Mariama Madi, Seismic
Analyst, main Research fields: CTBT Applications in
COMOROS. Email: mariabdjul@hotmail.com
-Karthala Volcano: major Seismic Identification
(Fig.1)
Fig.1: National Data Centre, Seismic Support data to
the Volcano Observatory, Relevant CTBT Functions in
Comoros [1]

2. 2. Geological Background of Comoro-
Islands
Chain of 4 volcanic islands located at
the northern end of the Mozambique Channel
separating Madagascar from southeastern Africa.
Hawaiian volcanoes Morphology as for:
-Grand Comore (1148km2), hosting the active
“Karthala volcano” (rising to 2361 m .al)
-Moheli (211km2; 790m al.), dated to 2,2Ma
-Anjouan (424km2; 1595m al.), dated to 1.5Ma
-Mayotte (374 km2; 660m al.), dated to ~5.4 Ma
(Hajash and Armstrong, 1972; Emerick and
Duncan, 1982) [1].
In another aspect of these studies, the
rate of migration of volcano in the Comoros
would require excessive rates of spreading
across the African Rift from global study of the
motion of the young hotspot chains over the
mantle conducted by Gripp and Gordon (2002)
[2].
Fig.2: Comoro-Islands, located at the northern end of
the Mozambique Channel separating Madagascar from
southeastern Africa. From the recent to the old one, it
constituted by Grande-Comore (Ngazidja), Anjouan
(Ndzouani), Moheli (Mwali) and Mayotte (Maore). [4]
Karthala volcano remaining the
important seismic and infrasound source in the
Island, hosts intra-caldera Units as following:
-Olivine basalts (almost in the entire Island)
-Basalts scoria
-Thrown blocks
-Lava flows (19th
, 20th
centuries)
-Undated Lava flows
- Etc.
Caldeira zone of Karthala (Grande-Comore)
Fig.3: Geological map [5] of the intra-caldeira units
of karthala volcano (Grande-Comore). As the Biggest
Islands, the Recent and the one which hosts the active
Volcano, it was important to mention the Units within
the Crater as intra-caldeira Units.
3. Event Source characteristics
significant to CTBT Applications
Comoro-Islands are exposed to several
Naturals Hazards simultaneous to the entire
world affected. The country may assist to
Tsunami, radioactive, infrasound and seismic
effects, therefore, dealing with the
Comprehensive Nuclear Test Ban Treaty
Organization (CTBTO) as signatory member
state, the country earns Scientific and
Technological Supports through: Training
Geographic situation
Secondary crater
Principal Crater

3. Courses, Use of IMS (International Monitoring
Station) Data and IDC (International Data
Centre) Products, Capacity Building System
(Technical support), National Data Centre
establishment and other Researches expected
to ameliorate the scientific aspect of NDCs.
During the Science and Technology
Conference 2013, I preferred as subject field to
introduce the continental, oceanic (tsunami,
run-ups) Seismic aspect and the effects related
to, by including the “2004 Indian ocean
tsunami, Comoro-Islands”, “Infrasound Source,
volcanic ash layer from 2005 Phreato-
magmatic eruption in Gde-Comore”, and
“Seismic Source, Karthala volcano”.
Fig.4: the 2004 Indian Ocean and global tsunami
affected Comoros up to 6.9 run-ups along the coast
lines. Volcanic ash, Blocks, and gases are released
from the two phreatic eruptions in 2005. And two
among important seismic activities are recorded by
the IDC through CTBT International Monitoring
System in Comoro-Islands. [6]
4. 2004 Indonesian Tsunami:
Considerable Run-ups around Islands
a- SUMATRA-ANDAMAN Tsunami surveys in
Comoro Islands (South African Journal of
Geology “Book reference”.) [7]
Fig.5: The 2004 SUMATRA-ANDAMAN Tsunami
surveys in Comoro Islands conducted in 2006 and 2007,
reveled significant records of Run-up in almost 35 areas.
[8]
b- “NDC” National Data Centre Comoros
and Asians Experts Survey in Grande-
Comore in 10 February 2011.
The idea of survey was to evaluate the disaster
caused by the Indian Ocean tsunami in
Comoros as part of the Indian Ocean affected
zones. The survey was based on villager’s
Testimony; therefore, waves reached homes
implemented nearby coast lines, and hopefully
without any casualties. In Fact, after the 2006
and 2007 survey (Fig:5), we decided to reach
affected areas and people in order to evaluate
the damage, by choosing two villages in the
North areas most affected of Gde-Comore,
which are: “Bangoua-kouni” (11022’S
43022’E), and “Bouni” (11028’S 43023’E).

4. Fig.6: Bangoua-kouni: we surveyed two points, and
evaluated an average run-up of 2.52 m. Bouni: pointed
5 sites, we recorded 5.8m in ‘Bouni.1’ and 6.7m in
‘Bouni.2’. [9]
c- Field information summary: “Bangoua-
kouni”
- Record of Run-up: 2.52m
- Flat area along the coast line
- Sea wall height about 2.5m above sea
level
- Arriving of tsunami at 4:30-5:00 am
(Local time)
- Inundation line reach up to 50m distant
inland
- Inundation period was 3 hours before
retreating to the see
- First wave was the biggest and caused
inundation
d- Field information summary: “Bouni”
- Record of Run-up: 6-7m
- High slope area (hilly) along coast line
- Sea wall height about 3.0m above sea
level
- Arriving of tsunami at 4:30-5:00 am
(Local time)
- Inundation continued until 8:00-9:00 am
- None of the wave overtopping across
sea wall after 2004 tsunami
- First wave was the biggest and caused
inundation
5. Karthala Volcano: as an infrasound
source
Fi
Fig.7: relating to the CTBT official Infrasound Source
images, the active volcano in Grande-Comore is one
source evident causing during explosive eruption
considerable releases of gas particle and volcanic ashes
in Comoros.
a- Explosive eruptions in 2005:
Volcanic activities:
Successive seismic crises two years before are
followed by two important explosive eruptions
occurred in the “Principal Crater” (Fig: 3).
The 16 April and 25 November 2005 are
phreato-magmatic phases:
•Phase1: Interaction magma-water
•Phase2: explosive phase with enormous
quantity of ashes released into the atmosphere +
large blocks ejected
•Phase3: lava inside the crater replaced the
initial water
b- Eruption Results and Impacts:
Fig.8: the ‘After eruptions’ Damage and environmental
impacts
- Emission of steam into the atmosphere
- Considerable amounts of ash released
many days after
- Gas particle emissions: H2O, CO2, CO
(1%), and other undefined particles.
- However, Severe breathing problems in
the vicinity of Karthala
- Almost 5m accumulation mud in many
areas after rain
- Plants, water resources,... also affected
- …

5. 6- Karthala Volcano: Major Seismic
Identification Source
For decades Karthala has been the
“Home” of consistence volcanic activities. From
this issue the Volcano observatory was seeing
imperative to be installed in 1989 (Franco-
Comorian Cooperation) in terms of following
the evolution of its seismic background and the
aspect of eruptions in order to settle a sort of
volcanic disaster warming in Grande-Comore.
But in the present time, still the initiative needs
support for diverse reasons in terms of getting
accurate results and Data, receiving suspicious
volcanic activities and be “hands in hands” with
the ongoing technology.
As evident and most of time, seismic
activities (source: volcano) are natural and
physical steps to volcanic eruptions preceded by
‘Pressure-Temperature’ mechanisms.
During two centuries, Grande-Comore
has been shaken by numerous magmatic,
phreatic, and phreato-magmatic eruptions which
caused casualties (1903 and 1904) (Fig: 9),
affected the environment in general and caused
material damages.
Year Dates Location Type of eruption Surface
covered
(106
m2
)
Volume of magma
estimated (106
m3
)
Seismicity
felt
Damages
2007 13 January Secondary crater Magmatic (Summit) YES
2006 28 May Principal Crater Magmatic (Summit) -
2005 25 November Principal Crater Phreatio-magmatic -
2005 16 April Principal Crater Phreatio-magmatic -
1991 11 July Principal Crater Phreatic - No Magma YES YES
1977 5 - 10 April South-West Flank Magmatic eccentric 1.8 10.8 YES YES
1972 8 Sep - 5 October Caldeira Magmatic (Summit) 2.5 12 - -
1965 12 July Caldeira and
Secondary Crater
Magmatic (Summit) 0.05 0.15 - -
1952 10- 14 February Principal Crater Magmatic (Summit) - - - -
1948 22 April to 4 May Secondary Crater Magmatic (Summit)
1948 13- 16 June Principal Crater Magmatic (Summit)
and Phreatio-
magmatic
16 6 YES YES
1918 11 to 13 August North Rift zone Lateral-Magmatic 2.7 10 YES -
1918 25 - 26 August Principal Crater Phreatic 25 No Magma YES YES
1904 25 February to April North Rift zone Lateral-Magmatic 11 44 YES YES, one person
1903 - South-East Rift
zone
Gas Emissions - - - YES, 17 persons
1880 - South-East Rift
zone
Lateral-Magmatic 2.4 10 YES YES
1876 - South-East Rift
zone
Lateral-Magmatic 4 17 - -
1872 - North Rift zone Lateral-Magmatic 1.6 7.2 - -
1860 December South-East Rift
zone
Lateral-magmatic 5.5 30 - -
1859 - Rift-zone Lateral-magmatic 3.9 20 - -
1858 - Caldeira and Rift-
zone
Lateral-magmatic 12.5 63 - -
1857 - South-East Rift
zone and Caldeira
Lateral-magmatic 10 56 - YES
1848 - South-West Flank Eccentric Magmatic 3 16 - -
1830 - - Magmatic - - - -
1828 - - Magmatic - - - -
1821 - - Magmatic - - - -
1814 - - Magmatic - - - -
1808 - - Magmatic - - - -
Table: Chronology of Karthala Volcano Eruptions
Fig.9: Archives of Karthala volcano eruptions (1808 – 2007). [10]

6. In 2005 Phreatic and phreato-magmatic
eruptions were preceded by considerable
volcanic crises during two years. [11]
Fig.10: In 2003, almost two months (October- December)
separated two intensive magma activities. One year
after (December 2004) the 3rd
major crisis took place
within two years (2003-2004). The 16 April 2005
explosive eruption occurred in the Principle crater of
Karthala.
6-1. Data acquisition: Volcano
observatory
Still the acquisition system “Earthworm”
considered as “old” software is being used.
Struggling access and Data analyses, One of the
big issues of the observatory is getting one the
software using by observatories in the worlds.
2 types of acquisition:
- Continuous Data
“Small” events (~ Mg 1, 1.5, 2 ~) saved as for:
Seismic background and for big (~Mg 4~)
events analyses, or for other volcanic-seismic
Research purposes, etc.
- Trigger Data
“Big” Events (≥ Mg 4): These data are
considered to be analyzed for the Event location.
6-2. National Data Centre
This NDC as IDC (International Data
Centre) relevant CTBT function is playing a
major role of getting International Monitoring
System (IMS) Data and Products. The access
and analyzing of international, regional and local
seismic Data is a proof of being a tremendous
and Relevant for controlling both the oceanic
aspect ( earthquakes, understand tsunami
effects…) of the Comoro-Islands and the
continental aspects (seismic-volcanic,
earthquakes, …) of Grande-Comore itself.
However, what the National Data Centre
brings to the seismic natural events in Comoros
and the Seismic Events from the Volcano
activities in Grand-Comoro Island?
- Two among important seismic events in
the North part of Comoro Islands, recorded by
the International Data Centre ‘IDC’ in Vienna,
were out of the Observatory Control:
Region: Northwest of Madagascar,
COMOROS:
Event no1: Date: 14 October 2010.
Time: 10:03:33.9, Latitude: 10.28S, Lon: 42.81E
Magnitude mb: 4.5
Event no2: Date: 20 march 2013.
Time: 05:21:56.8, Lat: 11.73S Lon: 42.38E
Magnitude mb: 4.2 (Source: IDC secure website,
IMS Data) [12]
Event no1: Event Analysis:
“National Data Centre”
Fig.11: this image resumes the steps of analysis using
“Geotool” software, design for NDC Analysis purposes.
BOSA (S. Africa), KMBO (Kenya), ATD (Djibouti),

7. AKTO (Kazakhstan), are some of the stations recording
the Event. After getting the output, waveforms are
filtered to detect clear signals, in order to pick arrivals
(Pg, Lg, Pn, Sn, P, S … etc) with which the Location is
possible.
Event location
Fig.12: the location shows a source point on Comoros,
but accurately the zooming illustrated the exact source
of the event which is not right on the continental area,
but in a distance of ~130 km from the crater to a point
in the ocean. The National Data Centre located the
Event by: Latitude: -11.36 S, Longitude: 42.78 E, Depth:
11, Time: 2010 Oct 14 at 10:03:31, Magnitude: 4.8
Event no2: Event analysis
Fig.13: this Regional event is the recent one in the
northwest oceanic region of Madagascar (COMOROS)
in 2013. KMBO (Kenya), OPO, are two among the
stations recording the event, where Pn, Sn arrivals are
clearly picked. During analysis picking phases is the
important step of locating event with much
concentration. Otherwise an arrival picked by error
brings the event in another side of the Globe.
Event Location
Fig.14: As for the 1rst location, it was compulsory to
know exactly the source of event, while the location on
the map still appears like on the land. But relay on
Google measurement we recorded a distance of almost
~80 km from the Karthala crater to the source. This
determined distance was possible from the geographical
coordinates of the event given by the CTBT SEL1
automatic recorded Data products. From this analysis,
the NDC located the Event by: Latitude: -11.86,
Longitude: 42.19, Depth: 0.0000, Time: 2013 march 20
at 05:21:55, Magnitude: 3.99 to 4
Conclusion
Comoro Islands is geographically a
strategic area of oceanic natural activities in
terms of earthquakes and tsunami in the Indian
Ocean. Geologically complex, the country
composed by four Islands, Between Mayotte the
old one (~5.4 ma apparition) eroded and
surrounded by a nearly continuous coral reef
averaging 5 km in width (Ref. South African
Journal of Geology Book: Page 344), and
Grand-Comore the youngest hosting the active
Volcano (Karthala, altitude: 2360 m) in
Comoros.
The explosive aspect of eruptions (Gas
particles, ashes, steam, etc...) accelerates the
existence of infrasound source that Karthala

8. volcano remains the 1rst cause in the country.
And as evident, it (explosive eruption) selected
by CTBT as one of the Infrasound sources
within the International Monitoring System, and
for further research purposes.
For the Seismic aspect which is the
basic of our research in this subject, after
comparing activities at the volcano observatory
to the National Data Centre ’NDC’ (CTBT
related functions), we realized that:
-Seismic events from “few” kilometers of the
sea areas surrounding the Islands are not
recorded by the Volcano Observatory: In fact,
from this issue the National Data Centre is
playing a tremendous role as CTBT Relevant
functions in the country in terms of Seismic
Event analyses with much confidence receiving
International Data and Products from the
International Data Centre ‘IDC’ by the IMS.
-Comparison of the NDC Analysis results to the
IDC Experts analyses.
-And etc…
From these Points, the purpose of identifying
characteristics of Oceanic and Continental
events in Comoros is for Civil and Scientific
uses, but also to enhance through our countries
as member states the CTBT Treaty compliance
for a secured world.
Acknowledgements:
-The Comprehensive nuclear Test-Ban Treaty
Organization: CTBTO
-The ‘NDC’ National Data Centre-COMOROS
-The Volcano observatory, CNDRS, Moroni-
Comoros
References
[1] Fig: 1:“National Data Centre, seismic support data
support to the Volcano observatory, Relevant CTBT
Functions in Comoros”, designed by the Author Ms.
Mariama MADI, National Data Centre, CNDRS, Moroni-
Comoros.
[2] Mayotte Island dated at ~5.4 Ma (Hajash and
Armstrong, 1972; Emerick and Duncan, 1982), “South
African Journal of Geology” Page: 344
[3] Global study of the motion of young hotspot chains
over the mantle (Gripp and Gordon), “South African
Journal of Geology” Page: 344
[4] Fig.2: Google earth and satellite images joined and
designed by the Author Ms. Mariama MADI, National Data
Centre, CNDRS, Moroni-Comoros.
[5] “Volcan0-tectonic” Map of the Grande-Comore by
Patrick Bachelery and Jean Coudray, Earth Science
Department, University of La Reunion, 1993.
[6] Fig.4: Designed by Author Ms. Mariama MADI,
National Data Centre, CNDRS, Moroni-Comoros.
[7] 2004 Sumatra-Andaman Tsunami Surveys in Comoro-
Islands…., “South African Journal of Geology” Page: 344
[8] Fig.5: Google earth images and South African Journal
of Geology Data joined and designed by the Author Ms.
Mariama MADI, National Data Centre, CNDRS, Moroni-
Comoros.
[9] Fig.6: Product of survey by the Team, image designed
by the Author Ms. Mariama MADI, National Data Centre,
CNDRS, Moroni-Comoros.
[10] Chronology of Karthala volcano eruptions, Volcano
Observatory, CNDRS (National Centre of Sciences
Research and Documentation), Moroni-Comoros.
[11] Seismic events (2003-2005) recording, Volcano
Observatory, CNDRS (National Centre of Sciences
Research and Documentation), Moroni-Comoros.
[12] 10 October 2010, 20 march 2013 events from SEL1
automatic Data, International Data Centre Secure website,
Vienna-Austria.