Seismic
and tsunami Hazard (Sulawesi island)
TOPIC : SAFETY
IN THE FIELD (Prevention & Mitigation of Risk Tsunami Disaster)
Date/Time : 20 October 2014
By : I Made Utarka
I. The
concept note covers the following topics:
1.Tsunami characteristics,
2.Do or Not to Do in pre, during, and
post-tsunami time phases ,
3.Tsunami risk in Indonesia and its
assessment in any given area,
4.Multi-hazard situation in coastal regions of
Indonesia and mitigation measures ,
5.Specific design solutions against various tsunami effects ,
6.Warning systems and communication,
7.Institutional arrangement and design criteria
What
is a tsunami? Tsu = pelabuhan ; nami = gelombang
A tsunami is a series of waves with a
long wavelength and period (time between crests). Time between
crests of the wave can vary from a few minutes to over an hour.
How
are tsunamis generated?
•Tsunamis are generated by any large, impulsive
displacement of the sea bed level.
• Earthquakes
generate tsunamis by vertical
movement of the sea floor. If the sea floor movement is horizontal, a
tsunami is not generated. Earthquakes of M > 6.5 are critical for tsunami
generation.
•Tsunamis are also triggered by landslides into or
under the water surface, and can be generated by volcanic activity and
meteorite impacts
How big is a tsunami?
•Tsunamis range
in size from centimeters to over 30 m height. Most tsunamis are less than 3 m
in height.
• In deep water (greater than 200 m), tsunamis
are rarely over 1m high and will not be noticed by ships due to their long
period (time between crests).
• As tsunamis propagate into shallow water,
the wave height can increase by over 10 times.
• Tsunami
heights can vary greatly along a
coast. The waves are amplified by certain shoreline and bathymetric (sea
floor) features.
• A large tsunami can flood land up to more
than 1.5 km from the coast.
The force of some tsunamis is enormous. Large
rocks weighing several tons along with boats and other debris can be moved
inland hundreds of feet by tsunami wave activity. Homes and other buildings are
destroyed.
PLTD 10 MW dihanyutkan Tsunami sejauh 4km ke daratan , beratnya sekitar 5000 ton
WHAT TO DO OR NOT TO DO UNDER RISK FROM TSUNAMI
(Apa yang dilakukan dan tidak dilakukan dalam keadaan bahaya karena Tsunami)
—You
should find out if your home, school, workplace, or other frequently visited
locations are in tsunami hazard areas.
—Know
the height of your street above sea level and the distance of your street from
the coast or other high-risk waters.
—Evacuation
orders may be based on these numbers.
—Plan
evacuation routes from your home, school, workplace, or any other
place
you could be where tsunamis present a risk.
you could be where tsunamis present a risk.
—If
possible, pick areas (30 meters) above sea level or go as far as 3 kilometers
inland, away from the coastline.
—You
should be able to reach your safe location on foot within 15 minutes
—Be
prepared to evacuate by foot if necessary
—If
your children's school is in an identified inundation zone, find out what the
school evacuation plan is.
—Find
out if the plan requires you to pick your children up from school or from
another location.
—Practice
your evacuation routes.
(Praktekan jalur evakuasi anda)
—Familiarity
may save your life. (Dengan memahami semua mungkin akan menyelamatkan nyawa anda)
—Use
a Weather
Radio
or stay tuned to a local radio or television station to keep informed of local
watches and warnings. (gunakan radio yang menyiarkan ramalan cuaca, radio lokal atau televisi untuk menjaga tetap mendapat informasi terakhir kondisi peringatan setempat)
—Talk
to your insurance agent. (Bicarakan dengan agen asuransi anda)
—Homeowners'
policies may not cover flooding from a tsunami. Ask about the Flood Insurance
Program. (Kebijakan pemilik rumah mungkin tidak mengcover banjir karena tsunami, Mintalah programasuransi karena banjir)
—Discuss
tsunamis with your family. (Diskusikan Tsunami dengan keluarga anda)
—If
you are visiting an area at risk from tsunamis
Check
with the hotel, motel, or campground operators for tsunami evacuation
information
and
find out what the warning system is for tsunamis. It is important to know
designated escape routes before a warning is issued.
Pontensi Tsunami di Indonesia (source : website BMKG)
Indonesia merupakan negara yang rawan terhadap tsunami, terutama kepulauan yang berhadapan langsung dengan pertemuan lempeng Eurasia, Indo-Australia dan Pasifik, antara lain Bagian Barat P. Sumatera, Selatan P. Jawa, Nusa Tenggara, Bagian Utara Papua, Sulawesi dan Maluku, serta Bagian Timur P. Kalimantan
Peta Tektonik dan Gunung Berapi di Indonesia. Garis biru melambangkan batas antar lempeng tektonik, dan segitiga merah melambangkan kumpulan gunung berapi. Sumber: MSN Encarta Encyclopedia
TSUNAMI WARNING AND COMMUNICATION SYSTEM
—International
Status of Tsunami Warning and Communication System
—Tsunami
Warning System is based on the concept that Tsunamis travel at much slower
velocity (500 to 700 km per hour or 0.20 km/sec) as compared to seismic waves
(6 to 8 km per second).
—after
the occurrence of a damaging earthquake and quick determination of epicenter,
warning time of a few minutes to 2 to 3 hours is available depending upon the
distance from the epicenter to the coast line
—PTWS
(Pacific Tsunami Warning System) -26 Int’l member state, the TWS center in Ewa
beach-Hawaii, has the following
components:
—Seismometers
including ocean bottom seismometers
—Tide
gauge stations/Seal level recorder.
—Pressure
recorder in the ocean bottom by moored systems
—Satellite
based communication links.
