Post on 06-Jun-2018
Principles of the Seismology and Seismic
Engineering
Assoc. Prof. RNDr. Dana Prochazkova, PhD., DrSc.
Czech Technical University in Praha
CONTENT
Introduction
Earthquake causes
Earthquake characteristics
Earthquake impacts and their consequences
Seismic regime
Seismological characteristic of Europe
Seismic vulnerability, mitigation, prevention and response
Principles of seismic protection in national standards, EU civil
protection directives and the IAEA standards
Earthquake
- is a physical phenomena that is a consequence of
processes that lead to accumulation of energy in
limited space in the Earth interior and to its sudden
release if energy size exceeds physical material limits
(stress limit, phase transition limit),
- is observed as vibrations of the Earth's surface of a
different intensity,
- causes harms and losses on human assets, i.e.
human lives and health, property, infrastructures and
environment. Greek philosopher Aristotle classified earthquake
into 6 categories according to observed Earth ´s surface
movements. Chinese scientist Chan Chen constructed instrument
for earthquake registration in 132 AD.
Seismology – science dealing with earthquakes
Seismic engineering – the discipline the aim of which
is to construct infrastructures and buildings resistant to
earthquake and similar phenomena impacts and by this
way to protect human lives and health and human
property.
Seismicity – general term.
Instrumental seismology – half of 19th century.
1897 – mathematical theory of the P (longitudinal –
primary), S (transversal – secondary) a L (surface) waves
Physical models of earthquake – rheology.
Earthquakes – enable the Earth's interior research
(Earth's crust, mantle, external core, internal core and its
parts).
Bucharest - March 4, 1977
Spitak - December 7, 1988
Dolní Žandov - December 21, 1985
Petrochemie in Izmit – August 17, 1999
Petrochemie in Izmit – August 17, 1999
Petrochemie in Izmit – August 17, 1999
Japan – March 11, 2011
Zaplavené letiště v Sendai
Japan – March 11, 2011 – Sendai airport
Tsunami se blíží k JE Fukushima JE po průchodu tsunamiJapan – March 11, 2011 - Fukushima NPP
After earthquake After tsunami
Recorded seismic events:
• natural earthquakes,
• induced earthquakes – man-made, induced by human activities
• artificial explosions,
• vibrations of natural or artificial origin – consequences of technological processes and natural phenomena as fall of meteorites, aircrafts, bombs etc.
Tsunami - waves on sea induced by earthquake the focus
of which is under the sea bottom.
Mikroseisms – permanent Earth's surface vibration.
Faults – foci of natural earthquakes in Earth's Crust and Upper Mantle
Strike slip
Thrust
Normal
Natural earthquakes are of:
• tectonic origin (90%),
• volcanic origin (7%),
• collapse of underground spaces (3%)
The most harms and losses on human assets are caused by
tectonic earthquakes.
Earthquake epicentres in last 800 years
Microearthquakes 1980 - 2000
Induced (man-made) earthquakes – artificially triggered
seismicity
• cause - the perturbation of the underground mechanical equilibrium, due
to industrial activities (mining, dams, geothermal, hydrocarbon reservoirs),
induce deformation of involved sites,
• located in different tectonic settings,
• types:
* reservoir - induced seismicity - e.g. Lake Kremasta in Greece 1966,
* rockbursts – mining – rockfalls, shaking, bumps, outbursts (methane
release),
* seismicity triggered by injection of fluids into rocks - special
technology of mining,
* seismicity triggered by withdrawn of fluids from surface formations –
special technology of mining,
* earthquakes stimulated by seismic vibration signals - special
technology of mining,
* stimulated by artificial explosions (mining regions, test sites).
Earthquake foci
– mostly on lithosphere plates boundaries
Daily is recorded ca 8000 earthquakes with magnitude 2 or
lower
Annually is recorded:
• ca 7000 – 9000 medium earthquakes with magnitude 4 and
higher,
• ca 18 – 20 strong earthquakes with magnitude 6 – 7,
• at least 1 very strong earthquake with magnitude 8 and
higher
Earthquake Mw Mo (dyne-cm)
1960 Chile 9.6 2.5 x 1030
1964 Alaska 9.2 7.5 x 1029
1906 San Francisco 7.9 9.3 x 1927
1971 San Fernando 6.6 1.0 x 1026
1976 Tangshan 7.5 1.8 x 1027
1989 Loma Prieta 6.9 2.7 x 1026
1992 Cape Medocino 7.0 4.2 x 1026
1994 Northridge 6.7 1.3 x 1026
1995 Kobe 6.9 2.5 x 1026
2004 Indonesia 8.4 1.3 x 1028
2010 Haiti 8.0 2.5 x 1027
2011 Japan 9.0 2.5 x 1029
Zemětřesení podle h jsou:mělká (méně než 50 km),
středně hluboká (50 – 400 km), hluboká ( 400 – 750 km )
E- epicentre – projection
Of H to Earth's surface
H – hypocentre – point
representation of focus
h – focal depth
Focus = focal domain Earthquake parameters • geographic co-ordinates of
epicentre E
• focal depth h
• size Earthquake size is measured by:
• Intensity (I),
• Energy (ET),
• Seismic energy (E)
• Magnitude (M) – Richter scale
• Ground acceleration (a),
• Ground velocity (v),
• Ground displacement (d),
• Seismic moment (Mo)
• Stress drop (σ)
Earthquakes are
* Shallow – h 50 km
* Intermediate - 50 ‹ h 450 km
* Depth - 450 ‹ h ca750 km
Total energy release at earthquake at time interval dt - dW
dW = mechanical energy (performed work – deformation + kinetic energy) +
heat energy
Seísmic energy – part of kinetic energy
E = ∫ ∫ ε dS dt,
0 S
- c
En = Eo exp (- d Dn) Dn .
Dependence of seismic energy on magnitude: log E = 11.3 + 1.8 M
I
A- seismic wave attenuation: log a = ---- - 0.5
3
Intensity attenuation
Kövestligethy formula: Io - In = 3 log (Dn / h) + 3 log e (Dn – h) α
Blake formula: Io - In = k log (Dn / h)
Bohemian Massif: log E = 12.40 + 1.13 Io
Gutenberg-Richter: log E = 11.3 + 1.8 M
Seismograph – instrument for recording the earthquakes (if ground
acceleration is measured – accelerograph)
Seismogram – earthquake record (in case of ground
acceleration recording – the accelerogram)
Magnitude – C. F. Richter 1935
M = log (A/T)max + (, h)
A – amplitude, T – period, - correction function (depends on wave type), - epicentral distance, h – focal depth)
Intensity - scales:
MCS, MSK-64, MM – 12 degree
JMA – 7 degree
Travel time curve - f (, h) - dependence of time spreading the
real wave on epicentral (hypocentral) distance – it depends on
wave type - t ( r ) = T - H ; time in site, time in focus.
O
SZP
C
M
granit
bazalt
Pg
P*
Pn
Isoseismal map - scenario of earthquake impacts
Typical isoseismals – isoseismal form depends on focal
region and on focal depth.
Empirical relations derived for Europe, M = 4.5 – 7.4, shallow
earthquakes:
log Mo = (9.95 0.24)+(1.40 0.14) M
log = - (3.15 0.24)-(0.29 0.09) R + (1.01 0.08) M
log = - (20.96 0.53)-(0.13 0.05) R + (1.26 0.18)log Mo
log u = - (2.60 0.11)-(0.39 0.09) R + (0.63 0.02) M
R- focal dimension, u – fault displacement
[Mo] = N m, [R] = km, [ ] = MPa, [u] = mm
Vrancea intermediate earthquakes:
log Mo = (8.98 0.80) + (1.5 0.12) M
PHYSICS: Mo
= μ AZ u
μ – torsion modulus, AZ
– active fault plane, u – fault displacement
EARTHQUAKE IS completely DESCRIBED BY 2
PARAMETERS – e.g. M and or Mo and !!!!!!
Relation among the focal parameters
Mw – Kawasaki / moment magnitude – derived from seismic moment (greater than
M calculated from seismic waves)
Seismogram: P vlny – 6 km/s; S vlny – 3.3 km/s; L vlny – 3 km/s
Length of time interval between P and S inputs depends on
epicentral distance and recording place.
With increase of epicentral distance the seismogram
complexity increase as a consequence of recording the
reflected, surface and other wave types.
There are earthquakes the records
of which do not respect present
standards on earthquake record
Spectrum of acceleration in near zone – different from distant
zone (red zone – strong dependence on local geological structure)
Differences in focal
mechanisms (documented
by amplitude rate S to P
changes) of near
earthquakes
Fault structure in
Western Bohemia –
causes of different
earthquake
mechanisms
Reaction of buildings to seismic waves
EXTREME
DISASTER
Human lives, health and security
Property
Welfare
Environment
Infrastructures
Technologies
Energy
Water
Sewage
Transport
Cyber
Finance
Emergency
Products
Governance
Nuclear
Chemical
Bio
DIRECT IMPACTS
Protection
measures
and activities
are prepared
only for
impacts denoted
by bold arrow
SECONDARY
IMPACTS
caused by
cascade
failures of
infrastructures
Accelerograms
Response spectra – RG 1.60 (US NRC)
Response spectra
Response spectrum - Atomenergoproject
Real response spectra
Intensity attenuation with distance – usually azimuthal
variations are observed in each focal region
log
E0 / E
0.1
1
10
100 log r 10
It corresponds to focal
zone dimension
Energy attenuation with distance
Acceleration attenuation with distance – strong regional
The earthquake foci mostly concentrate to regions
that we called “focal provinces – zones, regions”.
The boundary of focal provinces are defined as a
boundary that surrounds:
• all known earthquake foci occurring in the historical time
and in the case when there are the reliable evidence on pre-
historical foci from the research of paleoseismicity, so the
boundary also includes those,
• the region in which the earthquakes with the same
characteristics of seismic regime occur,
• the region with the same geological, tectonic and recent
movements characteristics.
Map of focal regions and regions with diffuse seismicity
Findings from research of earthquakes :
1. From earthquake foci space distribution it follows that earthquake foci
are mostly connected with faults.
2. In recent period only certain parts of faults are seismoactive, namely
in both, the vertical and the horizontal plane.
3. Earthquakes often originate on fault crossing. Mostly one of the fault
is preferred in historical time form earthquake occurrence viewpoint.
4. In some cases after strong earthquake connected with one fault
system it follows earthquake connected with other fault system – they
have different characteristics.
5. Isoseismal form in epicentral zone depends on fault-plane
mechanisms, in distance zone on material properties –
boundary r 2.5 h.
6. Isoseismal surface sizes depends directly on earthquake size and
focal depth and indirectly on intensity attenuation.
Seismic regime of focal zones:
• is variable in time and space,
• has a certain prevailing character in each focal zone,
• is described by:
* Benioff´s graphs,
* occurrence frequency,
* earthquake group types,
* space-time foci distribution,
* strong earthquake foci migration sometimes,
• in short term viewpoint is determined by value of stress
drop:
high - low value of the highest aftershock and low number
of aftershocks,
low - high value of the highest aftershock and great
number of aftershocks.
Benioff´s graphs
E – energy
t – time
Frequency graph – distribution of earthquake number
according to earthquake size – usually it is used the cumulative
frequency in which the sum starts at the biggest earthquake
Maximum Possible Earthquake in focal zone
• predetermined by physical focal zone condition,
• ways of determination:
* sum of size of maximum observed earthquake in the
historical time and 1 MSK-64,
* extrapolation of oscillations of the Benioff`s graph,
* curvature of magnitude – frequency graph in the
range of strong earthquakes,
* correlation of maximum observed earthquake with a
seismic activity defined for the selected level of
earthquake activity,
* theory of extreme values,
* correlation of maximum earthquake size with a fault
length,
* geodynamic factors.
Cheb
Tachov
Sokolov
Domaţlice
Strakonice
Klatovy
Rokycany
Příbram
Č. Krumlov
Prachatice
J. Hradec
Benešov
Beroun
KladnoRakovník
K. VaryLouny
Chomutov
Most Litoměřice
Teplice
Děčín
Č. Lípa
Liberec
MělníkMl. Boleslav
Nymburk
Kutná Hora Chrudim
Pardubice
Jičín
Semily
Trutnov
Jablonec
Náchod
Rychnov n./K.
Ústí n./O.
Havl. Brod
PelhřimovJihlava
Ţďár n./S.
Svitavy
Třebíč
Znojmo
Vyškov
Blansko
Prostějov
Olomouc
Přerov
Šumperk
Bruntál
Opava
Nový Jičín
Frýdek
Karviná
Vsetín
Zlín
Uh. Hradiště
Hodonín
Břeclav
PL
D
A SK
Plzeň
Ústí n/L
H. KrálovéPRAHA
Č. Budějovice
Brno
Ostrava
WIEN
BRATISLAVA
Jeseník
Map of maximum observed intensities (seismic zoning)
Earthquake groups
Foreshocks
Main shock
Aftershocks
Main shock
Aftershocks
Earthquake swarm
Earthquake swarm in Western Bohemia
Aftershock area – 200 x 500 km
Items that must be followed for seismic protection
Disasters – Hazard Risk - Emergency
Contexts:1. Human system is open dynamic system in which there are processes, actions,
phenomena and events the sources of which there are inside and outside of system.
The disasters are their results.
2. The disaster occurrence in a certain site and time causes in dependence on disaster
size and physical nature, and on amount and vulnerability of protected interests in a
given site the looses, damages and harms on protected interests, i.e. emergency.
At management there is necessary to distinguish
Related to protected interestsRelated to risk sources
Prevention, Renovation Preparedness, Response
DISASTERS EMERGENCIES
CAUSES CONSEQUENCES
impactsconditions
SYSTEM
SYSTEM
AT DISASTER
NO ACTION
CHANGES
WITH
DAMAGES
Disaster
SMALL CHANGE
Concept of possibilities of system behaviour at disaster.
Needle on balance that decides on consequences,
is system (managed subject) vulnerability.
Consequences
are results of
system
resilience,
vulnerability
and adaptability
and impacts
Protection principles
1. To distinguish causes (phenomena) and
consequences (events, emergency situations)
Earthquake = Disaster
From safety viewpoint: Causes are characterized by quantity hazard.
Consequences are characterized by quantity risk.
2. For human protection we must protect
public assets and to consider all disasters,
i.e. so called „ALL HAZARD APPROACH“
3. To consider that reality is system of systems
(i.e. set of systems that are mutually
interconnected) - to consider vulnerability,
resilience and adaptation capacity and the reality that we need to ensure
technological environmental
social
Coexistence
of systems
4. To use the third step management and
legislation for effective emergency and crisis
management
Legislation Management structure
Prevention - introduction of
protection measures against
disasters occurrences and
disasters impacts
enhancements, active and
passive.
Preparedness (and
readiness) - introduction of
measures enhancing our
capability to put disasters
under the control.
Response - implementation
of measures putting the
disaster impacts under the
control, with adequate losses
and adequate sources.
Renovation -
implementation of measures
for assurance of area
reconstruction return to a
stabilized conditions and start
of further human society
development.
5. Safety Cycle.
6. The effectiveness of measures and activities
is different.
The most effective measures and activities by that we
can avert the disaster occurrences and mitigate their
impacts are preventive measures (procurators), the
effectiveness of which is the following:
1. Technical measures use in the area of land-use
planning - about 60 - 80%.
2. Population education and training - about 20 - 30%.
3. Emergency and crisis management (strategic
planning)-about 25 - 40%.
4. Installation of warning and alarm systems - about 9
- 40%.
7. Human, technical and financial sources,
forces and means are limited good
governance is necessary – tool decision
matrix
543210P / D
0
1
2
3
4
5
Unacceptable
Conditionally
acceptable, i.e. acceptable
with measures
Decision matrix for design disaster management: P – disaster occurrence
probability, D - impact size
Acceptable
8. To use all state tools for safety support:
1. Strategic safety management with aim security
and
sustainable development.
2. Training and education of population.
3. Specific training the technical and senior managers.
4. Technical standards, norms and regulations, i.e. the
regulation of processes that can or could result to an
occurrence (origination) of disaster.
5. Research – theoretical and experimental
6. Inspections.
7. Efficient forces for putting the disasters under the
control (e.g. fire-fighters, police, medical doctors).
8. Emergency and crisis managements belonging to
standard state strategic management.
Seismic tests – shaking table
9. Reserves for crisis management
1. Emergency management uses standard forces,
sources and means.
2. Crisis management uses standard + beyond
standard forces, sources and means
RESEARCH IS IMPORTANT
State safety management system ensuring the
disaster protection in the EU and its Member States:
1. Guarantees the protection of human lives and health,
property, environment and technical infrastructure.
2. Considers all relevant disasters with possible occurrence
on its territory and against relevant disasters it carries out
the prevention and preparedness with regard to their
impacts.
3. Forms the professional base, managerial structure,
efficient forces, means, substances and sources to ensure
protection of human lives and health, property,
environment and of the state.
4. Forms the professional base, managerial structure,
efficient forces, means, substances and sources to ensure
renovation after disaster and after crisis.
IAEA Safety Guides for seismic domain
1. IAEA 50-SG-S1 - Earthquakes and Associated Topics in Relation to
Nuclear Power Plant Siting: A Safety Guide. Vienna 1978.
2. IAEA 50-SG-S1 (REV 1) - Earthquakes and Associated Topics in
Relation to Nuclear Power Plant Siting: A Safety Guide. Vienna 1991,
59p.
3. IAEA No. NS-G-3.3. Evaluation of Seismic Hazards for Nuclear Power
Plants. Safety Guide. No. NS-G-3.3. ISBN 92-0-117302-4, IAEA,
Vienna 2002, 31p. www.iaea.org/ns/
4. IAEA No. SSG-9 - Seismic Hazards in Site Evaluation for Nuclear
Installations. Specific Safety Guide No. SSG-9. ISBN 978–92–0–
102910–2, IAEA, Vienna 2010, 62p. www.iaea.org/books
5. IAEA No. NS-G-1.6 - Seismic Design and Qualification for Nuclear
Power Plants. ISBN 92-0-110703-X, IAEA, Vienna 2003, 58p. www-
ns.iaea.org/standards/