SnT2015 Conference
Comoros Islands/Regional seismic sources and related effects
Ms.Mariama MADI NDC Manager, Seismic Data Analyst -Comoros-
Acknowledgement: Volcano Observatory Comoros: Shafik Bafakih, Moussa Moegni Ali PTS: Martin Kalinowski (Advice), Remmy PHIRI ( Data support), Ranon Josef le Bras (KML hydro-Data provider), Pierrick Mialle ( Infrasound details), Dale Robin (software)
This work is being performed based on the CTBTO Fellowship for Young Scien sts and Engineers 2014, with objec ve of raising awareness on natural Hazards inves ga on, However, how IDC Data contribute to Na onal Issues for Civil and Scien fic purposes and with interest of enhancing the scien fic Documenta on to the Na onal Ins tu on CNDRS-NDC-Comoros
SnT2015 Conference, Civil and Scientific Applications Abstract n°: T1.5-01 SnT2015 Conference
Outline
• Introduction
• Statistical approach of Local Events and SEL3 Seismic Data evaluation
• Events and Related Effects
• Summary
SnT2015 Conference, Civil and Scientific Applications Abstract n°: T1.5-01 SnT2015 Conference
I-Introduction
The Interest of evalua ng the local seismic ac vi es in the region of Islands rely on understanding how the level of local acquisi on behaves from volcanic ac vi es and seismic events in vicinity, with ≥ 1.5 Magnitude (Volcano-OBS) and ≥3.7/4 IDC- SEL3s events. And, how IDC Data and Products contribute to answer some ques ons in regard of small Islands geological Hazards (e.g: Comoro-Islands), furthermore, reframe the Use of Data for Research purpose.
The subject is focused on two main parts:
- Statistical approach of Local and SEL3s Seismic Data - Events and Related Effects
SnT2015 Conference, Civil and Scientific Applications Abstract n°: T1.5-01 SnT2015 Conference
Location
- Four principal islands, lying in a WNW–ESE line at the northern end of the Mozambique Channel - Grand Comore (1148km2), hosting the active “Karthala volcano” (rising up to 2361 m .al) (Lat: ~ 11°44’S/ Lon: ~43°20’E)
- Moheli (211km2; 790m al.) , dated to 2,2Ma (Lat: ~12°19’S/ Lon: ~ 43°44’E)
- Anjouan (424km2; 1595m al.) , dated to 1.5 Ma (Lat: ~12°13’S/ Lon: ~44°26’E)
- And Mayotte (374 km2; 660m al.),.dated to ~5.4 Ma, which is in an advanced stage of erosion and subsidence, and is encircled by a barrier reef…(Lat: ~12°48’S/ Lon: ~45°10’E)
SnT2015 Conference, Civil and Scientific Applications Abstract n°: T1.5-01 SnT2015 Conference Region and Target Sources
Chronology of Karthala Volcano
Seismic Events Region of Interest: Constained box Lat: -15/-9 Lon: 41/48
Years within the ‘2000-2014’ period of Interest
SnT2015 Conference, Civil and Scientific Applications Abstract n°: T1.5-01 SnT2015 Conference
IDC Data-record Ressources
IDC Products REBs-IDC, SEL3s 2000-2014 Seismic Data
SnT2015 Conference, Civil and Scientific Applications Abstract n°: T1.5-01 SnT2015 Conference • II-Statistical approach of Local Events and SEL3 Seismic Data evaluation Mg 6
5
4
3
2
1 Magnitude events, Comoros OBS SEL3 Magnitude threshold:SEL3s 0 7/24/1998 4/19/2001 1/14/2004 10/10/2006 7/6/2009 4/1/2012 12/27/2014 9/22/2017
SnT2015 Conference, Civil and Scientific Applications Abstract n°: T1.5-01 SnT2015 Conference
A- Issues raised from the evaluation process upon the local acquisition (earthquakes, volcanic-seismic activities,...) are likely to answer some of practical questions:
1- Gaps of Data generated from local seimic Network technical issues within the period Interest would have been fulfilled taking in to account SEL3s Data period, which is showing a continuity of recording, which could be interesting to understand the aspect of events in vicinity during the period were the local recordings were missing.
6
4
SEL3s 2
0 7/24/1998 4/19/2001 1/14/2004 10/10/2006 7/6/2009 4/1/2012 12/27/2014 9/22/2017 Period
2- Absence of Appropriated So ware for Local Data analyses and coherence would be fixed with some of the IDC purposes on NDC in-a-box so ware (…):
Local Data (volcanic activities) Conversion to CSS Format for NDC analyses commitments.
SnT2015 Conference, Civil and Scientific Applications Abstract n°: T1.5-01 SnT2015 Conference Process: (From Suds to GSE)
7 from the 39 dmx format converted: a- File: “Winsuds290” into “c: driver” or other drivers b- Files Structure: c:\winsuds290 - bin - data - doc - etc - keys - lib c- Place of Data -data must be saved in \winsuds290\data\ Name file should be : YYYYMMDD*.dmx, YYYYMMDD and dmx are important, and (*) can be any combina on of strings. Ex: 20130201_003643_KA_904.dmx d- Conversion Into “windows Dos prompt” : - Run the script for February 01, 2013: \winsuds290\bin\convert2css.bat 2013 02 01 e.g. of files:
SnT2015 Conference, Civil and Scientific Applications Abstract n°: T1.5-01 SnT2015 Conference Converted data into ‘Geotool’ and Waveform Results are: Unfiltered waveforms Filtered Waveforms
SnT2015 Conference, Civil and Scientific Applications Abstract n°: T1.5-01 SnT2015 Conference B- Seismic activity region of Interest
1- West of Islands
SnT2015 Conference, Civil and Scientific Applications Abstract n°: T1.5-01 SnT2015 Conference 2- Regional Events and Facilities (IMS) Assessing IDC Regional Arrivals (Pn) we notice the importance of 3 components Stations in narrow area as for Comoros Islands, then how evolving the aspect of Data comparison, close events deduction and which of the IMS facilities record the most of Seismic events. Further, they many contribute to understand seismic records generate secondary effects, in the Region etc...
SnT2015 Conference, Civil and Scientific Applications Abstract n°: T1.5-01 SnT2015 Conference
Ex. 12 March 2014 Com.
SnT2015 Conference, Civil and Scientific Applications Abstract n°: T1.5-01 SnT2015 Conference
III- Events and Related Effects
SnT2015 Conference, Civil and Scientific Applications Abstract n°: T1.5-01 SnT2015 Conference
Effects in consideration
Analyses: The area (Lat:-15/-9 and Lon:41/48), reveal significant path of Knowledge that can contribute to many aspects of risks management, combining the 3 Technologies (Seismic, Infrasound, Hydroacous c). Some of Data showed strong usefulness to the Islands that contribute to disaster warning design for Small Islands; performance of the IDC Technology through IMS Network; but also contribute to enhance more the aspect of IDC products acquisi on and other related issues.
SnT2015 Conference, Civil and Scientific Applications Abstract n°: T1.5-01 SnT2015 Conference
1- Earthquake and hazard
An earthquake was felt massively in Anjouan Island and made the popula on of the Island in panic in the night of 12 March 2014.
Few damages have been seen in the west of the Island (Mutsamudu region), as the popula on has been witnessing at 20:43:32 night local me.
Tes monies: Interviewed: -:« I was scared » -: I though I would die, it was shaking roughly 8s short moment -: The last one accured in last February, with moderated quakes, but the 12 March one, definitely was 7 to 8s period but was enough to make few and moderate landslides on small parts of Mutsamudu mounts. -: ….etc….
SnT2015 Conference, Civil and Scientific Applications Abstract n°: T1.5-01 SnT2015 Conference
Event Location
SnT2015 Conference, Civil and Scientific Applications Abstract n°: T1.5-01 SnT2015 Conference 2- Infrasound detections generated by the 2005 and 2006 volcanic eruptions in Comoros (Gde-Comore Island)
Eruption period of consideration
From 2005 to 2006 the Volcano Observatory recorded sensitive seismic activities accelerated from continuing magma activities, and generated Explosive Eruptions.
Secondary Crater
Principal Crater
SnT2015 Conference, Civil and Scientific Applications Abstract n°: T1.5-01 SnT2015 Conference Reported by IDC Infrasound Expert: 3 sequences of Karthala volcano have been observed and recorded in IRED (Infrasound Reference Event Database) in 16 and 17 April 2005, and 28 May 2006. These erup ons have been reported in the Database of Smithsonian, at that me, the Infrasound Technology hasn’t been yet considered among the Reviewed event Bulle n REB records of the IDC.
17 April 2005 28 May 2006
SnT2015 Conference, Civil and Scientific Applications Abstract n°: T1.5-01 SnT2015 Conference 3- Seismic hazard and tsunami effects in Comoro-Islands
3-1- 2004 tsunami and Impacts in the Islands: A joined team (NDC included) has conducted surveys on two of the areas of interest in Gde-Comore Island, In 2006 and 2007 about 35 areas, were iden fied (South African Journal of Geology) during a survey. and part of the work was based on Villager Testimony
-Record of Run up: 6-7m -High slope area (hilly) along coast line -Sea wall height is about 3.0m above sea level -Arriving of tsunami at 4:30-5:00am local Time -Inunda on con nued un l 8:00 to 9:00am -None of the wave overtopping across sea wall a er 2004 Tsunami -First wave was the biggest and caused inunda on
SnT2015 Conference, Civil and Scientific Applications Abstract n°: T1.5-01 SnT2015 Conference 3-2- Importance of KML Data on raising tsunami awareness
These KML hydroacous c Data provided by the IDC reinforce the regional sta s cal statement on the expecta on of regional seismic sources likely to be genera ng a small or big tsunami in the area
SnT2015 Conference, Civil and Scientific Applications Abstract n°: T1.5-01 SnT2015 Conference The Indian Ocean known as hos ng major Sources of tsunami in the region, men oning the exis ng of subduc on zone along the Indonesian plate, remains a key area to scien fic inves ga on. The 2004 Sumatra-Andaman damaging Tsunami triggered the research path on the area of interest, and (unfortunately) contribute hypothe cally to assess future Sumatra Event sources in the Region. Representation of Data (Mg) through years Data Location
Tphase detections
SnT2015 Conference, Civil and Scientific Applications Abstract n°: T1.5-01 SnT2015 Conference Summary - Almost 828 (from 1.5 Mg) Data from the Observatory were evaluated - Missing local system data loca ons can be fulfilled through IDC Data and Products - Introducing exis ng Data recorded by the local network into the NDC in a box so ware applica ons to be analyzed and enhance the local bulle n - With the existence resources we can make scien fic local or regional commitments, Evalua ng regional hazards, the reason why, further sophis cate NDC so ware will be highly of Big interest
- Meanwhile: - As it is missing IDC mb Threshold values between 2000 and 2003 records, it would be important to see how to generate these Data in the IDC Database, AND, - The historical archives of infrasound Data generated by volcanic erup ons In order, both to support the Research aspect of the Ins tu ons showing interest to be provided this kind informa on.
SnT2015 Conference, Civil and Scientific Applications Abstract n°: T1.5-01 SnT2015 Conference
Thank you
Regional Course on NDC Capacity Building GHANA, Nov-Dec 2011
Empower the young Generation for a Future peaceful and Innovative world
SNT2013 SnT2015 Conference, Civil and Scientific Applications Abstract n°: T1.5-01