himalayan orogeny nepals earthquakes 2011.pdf copy · himalayan_orogeny_nepals_earthquakes_2011.pdf...
TRANSCRIPT
Photo Source: http://visibleearth.nasa.gov/view_rec.php?id=4753 Photo modified by MCMackiewicz
HIMALAYAN OROGENY: NEPAL’S EARTHQUAKES By Michael C. Mackiewicz Professor Geology College of Southern Maryland [email protected]
India
China
Bhutan
July 2011
1
PRESENTATION GOALS AND OBJECTIVES
Goal of this presentation is for the observer to gain a generalized overview of earthquake activity in Nepal.
Three objectives outlined below will be used to achieve this goal.
1. Illustrate why and how the Himalayan Mountains formed.
2. Various causes will be identified as to why earthquakes occur in Nepal, as well as identifying the primary triggering mechanism for the earthquakes.
3. Illustrate graphically the number of and frequency of recorded earthquakes of magnitude, M ≥ 4, occurring in Nepal in the previous 50 to 60 years since 2011.
2
The
Him
alay
a M
ount
ains
Rec
ords
one
of t
he m
ost d
ram
atic
, vi
sual
evi
denc
e of
the
Forc
es o
f Pla
te T
ecto
nics
.
Diag
ram
Mod
ified
from
: ht
tp:/
/cos
scie
nce1
.pbw
orks
.com
/f/1
2481
9270
7/M
odul
e10-
015.
gif
Sri L
anka
Indi
a la
nd m
ass
EURA
SIAN
PL
ATE Indi
a To
day
Him
alay
a m
ount
ain
rang
e fo
rmed
by
the
colli
sion
of t
he In
dian
Pla
te w
ith E
uras
ian
(Tib
etan
) Pla
te a
roun
d 55
mill
ions
yea
rs
ago
(see
figu
re).
Abo
ut th
at ti
me,
sc
ient
ists
bel
ieve
that
the
north
war
d m
ovin
g In
dian
pla
te fi
rst c
ollid
ed in
to th
e so
uthe
rn e
dge
of T
ibet
an (E
uras
ian)
pla
te.
This
con
tinen
tal –
con
tinen
tal c
ollis
ion
(Con
verg
ent P
late
Bou
ndar
y) k
icke
d-of
f th
e H
imal
ayan
Oro
geni
c Pr
oces
s (m
ount
ain
build
ing)
.
This
cont
inen
tal –
con
tinen
tal
colli
sion
cont
inue
s tod
ay!
3
The
lead
ing
edge
of t
he p
late
(oce
anic
cru
st) c
arry
ing
Indi
a is
subd
ucte
d be
neat
h th
e Eu
rasi
an p
late
. The
land
mas
ses (
cont
inen
tal c
rust
) col
lide
and
push
ing-
up th
e la
nd
mas
s. Th
is c
ollis
ion
cont
inue
s tod
ay.
Diag
ram
s Mod
ified
from
Sou
rce:
htt
p://
coss
cien
ce1.
pbw
orks
.com
/
Sim
ply
put:
As t
he c
ontin
enta
l cru
st o
f bot
h pl
ates
mer
ge
into
one
, the
inte
rven
ing
ocea
nic
sedi
men
ts
and
rock
get
sand
wic
hed
in b
etw
een
both
cr
usts
. Th
is p
ushi
ng a
nd p
iling
of r
ock
on-
top-
of ro
ck b
uild
s-up
the
Him
alay
as
Mou
ntai
ns.
Two
tect
onic
s pl
ates
col
lide
into
eac
h ot
her;
the
Indi
a Pl
ate’
s oc
eani
c cr
ust
bein
g sl
ight
ly d
ense
r sin
ks u
nder
(s
ubdu
cted
, pul
led
bene
ath)
the
less
den
se
Eura
sian
Pla
te.
Wha
t Hap
pens
Dur
ing
this
Con
tinen
tal-C
ontin
enta
l Col
lisio
n?
Bas
ed o
n re
cent
Glo
bal P
ositi
onin
g Sy
stem
(GPS
) dat
a, th
e In
dian
pla
te m
oves
nea
rly 5
cm
per
yea
r (ab
out 2
-inch
es)
plow
ing
into
Asi
a. H
owev
er, G
PS d
ata
also
sugg
ests
that
Tib
et p
ushe
s onl
y ab
out 3
.2 c
m (1
.3 in
ches
) int
o A
sia
each
yea
r.
Indi
a Pl
ate
Eura
sian
Pla
te
4
Maj
or C
onse
quen
ce o
f thi
s Con
tinen
tal-C
ontin
enta
l C
ollis
ion
and
Plat
e Su
bduc
tion
are
Eart
hqua
kes
Dia
gram
Mod
ified
from
: ht
tp://
ww
w.g
eol.u
csb.
edu/
facu
lty/h
acke
r/geo
102C
/lect
ures
/Hin
duK
ush.
jpg
Stre
sses
bui
ld-u
p as
a re
sult
of th
e co
ntin
ents
col
lidin
g –
rele
ase
of th
is st
ress
(or
ener
gy) i
s in
the
form
of
earth
quak
e.
Ana
logo
us to
und
erst
andi
ng th
is
rele
ase
of e
nerg
y
- th
ink
of tw
o ca
rs c
ollid
ing
head
-on,
the
two
cars
repr
esen
t th
e tw
o Pl
ates
, as t
he c
ars c
ollid
e th
e im
pact
rele
ases
ene
rgy
shat
terin
g th
e ve
hicl
es.
Eart
hqua
kes
5
An
eart
hqua
ke c
an ta
ke th
e fo
rm o
f eith
er:
•A
sudd
en a
nd s
omet
imes
vio
lent
mov
emen
t of t
he e
arth
s’ su
rfac
e ca
used
by
the
rele
ase
of b
uilt-
up e
nerg
y in
the
earth
’s c
rust
, or
•It
can
be a
slo
w re
leas
e of
ene
rgy
occu
rrin
g ov
er a
long
er ti
me
inte
rval
- on
the
orde
r of d
ays,
wee
ks, m
onth
s, o
r yea
rs.
Eart
hqua
kes c
an b
e ca
used
by
diffe
rent
pro
cess
es,
such
as:
¾Te
cton
ic a
ctiv
ity,
¾Vo
lcan
ic e
rupt
ions
,
¾M
ass
was
ting
(land
slid
es, a
vala
nche
s),
¾Is
osta
tic re
boun
d,
¾A
tmos
pher
ic p
heno
men
a (to
rnad
oes,
mon
soon
s),
¾Ex
trate
rres
trial
(met
eorit
ic/a
ster
oid
impa
cts)
, and
¾M
an-m
ade.
6
How
ever
, the
mos
t com
mon
type
of e
arth
quak
es a
re
Tect
onic
Ear
thqu
akes
.
Tect
onic
Ear
thqu
akes
occ
ur w
hen
rock
s in
the
earth
's cr
ust f
ract
ure
due
to g
eolo
gica
l for
ces c
reat
ed b
y m
ovem
ent o
f tec
toni
c pl
ates
.
Ther
e ar
e th
ree
prim
ary
type
of p
late
tect
onic
bo
unda
ries
: 1.
Div
erge
nt (e
xten
sion
al),
2.Tr
ansf
orm
(slid
ing
past
eac
h ot
her)
, and
3.
Con
verg
ent (
com
pres
sion
al).
Ea
ch o
f the
Pla
te b
ound
arie
s are
subj
ect t
o di
ffer
ent i
nter
-pla
te st
ress
es, p
rodu
cing
thre
e ge
nera
lized
type
s of e
arth
quak
es.
A.
Exte
nsio
nal,
B.
Com
pres
sion
al, a
nd
C.
Tran
sfor
m
7
The
Him
alay
an K
ingd
om o
f Nep
al is
loca
ted
at th
e bo
unda
ry b
etw
een
Indi
an
and
Eur
asia
n (T
ibet
an) t
ecto
nic
plat
es p
laci
ng th
e co
untry
in a
hig
hly
se
ism
ical
ly a
ctiv
e re
gion
of t
he H
imal
ayas
.
Alth
ough
Nep
al e
xper
ienc
es m
any
earth
quak
es, a
maj
ority
of t
he
docu
men
ted
earth
quak
es a
re b
elow
a m
agni
tude
of 7
.
Earth
quak
es a
re th
e re
sult
of se
vera
l nat
ural
geo
logi
c pr
oces
ses.
How
ever
, re
gard
less
of r
ecen
t adv
ance
s in
seis
mic
mon
itorin
g, c
ausa
tiona
l eff
ect
anal
ysis
and
eve
nt fo
reca
stin
g, p
redi
ctin
g w
hen
a m
ajor
ear
thqu
ake
even
t m
ay o
ccur
is te
nuou
s at m
ost.
Nep
al S
eism
ical
ly A
ctiv
e
Earth
quak
e M
agni
tude
s Exp
erie
nced
in N
epal
Pred
ictin
g Ea
rthqu
akes
in N
epal
Nep
al’s
Ear
thqu
ake A
ctiv
ity
8
Nep
al -
Seism
icity
Map
M
ap so
urce
Uni
ted
Stat
es G
eolo
gica
l Sur
vey,
dow
nloa
ded
24 Ju
l 201
1 fr
om
http
://e
arth
quak
e.us
gs.g
ov/e
arth
quak
es/w
orld
/nep
al/s
eism
icity
.php
Note:
Eac
h ci
rcle
repr
esen
ts a
reco
rded
ear
thqu
ake.
Mos
t of N
epal
’s e
arth
quak
es a
re re
lativ
ely
shal
low
( ≤
33
Km
dep
th) a
nd lo
cate
d ne
ar th
e es
timat
ed b
ound
ary
betw
een
the
Indi
a - E
uras
ian
Plat
es.
9
http
://w
ww
.nse
t.org
.np/
nset
/htm
l/EQ
%20
in%
20ne
pal/f
req.
jpg
The
2 m
ost c
omm
on c
ause
s of e
arth
quak
es o
ccur
ring
in N
epal
are
; �
Com
pres
sion
al (c
ontin
enta
l-con
tinen
tal c
onve
rgen
ce),
and
�Ex
tens
iona
l. N
ote:
Com
pres
sion
al ty
pe e
arth
quak
es a
re b
elie
ved
to b
e by
far t
he m
ost d
omin
ant
type
; onl
y re
cent
ly is
ther
e m
ount
ing
evid
ence
that
ext
ensi
onal
type
may
be o
ccur
ing.
The
grap
h (le
ft) p
rese
nted
by
the
Nat
iona
l Soc
iety
of
Earth
quak
e Te
chno
logy–
NEP
AL
show
s th
e se
ism
ic
reco
rd b
etw
een
1911
to 1
991.
Not
e: T
hat a
tota
l of 7
1 ea
rthqu
akes
are
repo
rted
over
th
e 80
-yea
rs b
etw
een
1911
to
1991
; a ra
te o
f nea
rly 1
per
ye
ar.
10
The
next
two
slid
es il
lust
rate
s th
e fr
eque
ncy
of
reco
rded
ear
thqu
ake
occu
rren
ces
in N
epal
bet
wee
n Ju
ne 1
994
to J
uly
2011
.
Gra
phic
al p
rese
ntat
ion
of d
ata
used
in p
repa
ring
the
follo
win
g Fi
gure
s 1
and
2 w
ere
com
pile
d fr
om d
ata
mad
e av
aila
ble
by,
Nat
iona
l Sei
smol
ogic
al C
entre
D
epar
tmen
t of M
ines
and
Geo
logy
La
inch
aur,
Kat
hman
du, N
epal
Te
leph
one:
977
-1-4
4101
41, 9
77-1
-442
1828
Fa
x: 9
77-1
-441
2056
Em
ail:
nscd
mg@
mos
.com
.np
W
ebsi
te: h
ttp://
ww
w.s
eism
onep
al.g
ov.n
p/In
trodu
ctio
n.ht
m
Plea
se c
onta
ct th
e N
atio
nal S
eism
olog
ical
Cen
tre b
y go
ing
to th
eir
web
site
and
dow
nloa
ding
th
e ra
w d
ata;
you
may
als
o co
ntac
t me
at th
e em
ail a
ddre
ss p
rovi
ded
on
the
title
pag
e of
this
pr
esen
tatio
n fo
r the
dat
a. P
leas
e gi
ve a
ll ap
prop
riate
cre
dit w
hen
usin
g th
is da
ta.
11
05101520253035
MO
NTH
LY R
EPO
RTED
EA
RTH
QU
AK
ES IN
NEP
AL,
M ≥
4
June
199
4 to
Jul
y 20
11
TOTA
LS
Number of Earthquakes, M ≥ 4
http
://w
ww
.sei
smon
epal
.gov
.np/
past
_ear
thqu
akes
.htm
Figu
re 1
: Dat
a us
ed to
pre
pare
the
abov
e gr
aph
was
com
pile
d an
d ta
bula
ted
from
dat
a m
ade
avai
labl
e by
the
Nat
iona
l Se
ism
olog
ical
Cen
tre, D
epar
tmen
t of M
ines
and
Geo
logy
, Lai
ncha
ur, K
athm
andu
, Nep
al.
12
051015202530
1992
1997
2002
2007
2012
Year
AN
NU
AL
NU
MB
ER O
F N
EPA
L EA
RTH
QU
AK
ES ,
M ≥
4
1994
to 2
011ª
ª : 199
4 da
ta o
nly
for J
une
to D
ecem
ber;
201
1 da
ta o
nly
for J
anua
ry to
Jul
y
Number of Earthquakes, M ≥ 4
http
://w
ww
.sei
smon
epal
.gov
.np/
past
_ear
thqu
akes
.htm
Figu
re 2
: Dat
a us
ed to
pre
pare
the
abov
e gr
aph
was
com
pile
d an
d ta
bula
ted
from
dat
a m
ade
avai
labl
e by
the
Nat
iona
l Se
ism
olog
ical
Cen
tre, D
epar
tmen
t of M
ines
and
Geo
logy
, Lai
ncha
ur, K
athm
andu
, Nep
al.
281
Eart
hqua
kes i
n 17
yea
rs
Appr
oxim
atel
y 16
– 1
7 Ea
rthq
uake
s of M
≥ 4
/yea
r
13
The
last
slid
e (F
igur
e 2,
Slid
e Pa
ge 1
4) p
rovi
ded
info
rmat
ion
that
in
dica
tes
that
Nep
al e
xper
ienc
es a
ppro
xim
atel
y 16
– 1
7 Ea
rthq
uake
s of M
≥ 4
/yea
r.
14
How
ever
, the
gra
ph a
nd d
ata
pres
ente
d by
the
Nat
iona
l Soc
iety
of
Earth
quak
e Te
chno
logy–N
EPA
L (o
n Sl
ide
Page
10)
sug
gest
s th
at
betw
een
1911
to 1
991t
hat o
nly
abou
t 1
Eart
hqua
ke o
f M ≥
4/y
ear
QU
ESTI
ON
?
Is ea
rthq
uake
act
ivity
real
ly in
crea
sing?
Alth
ough
this
is n
ot a
geo
logy
cla
ss, i
t is i
mpo
rtant
to u
nder
stan
d a
little
how
the
Nep
al H
imal
ayan
regi
on is
geo
mor
phog
ical
ly d
escr
ibed
.
Ther
efor
e, th
e ne
xt 3
-slid
es p
rovi
de so
me
basi
c in
form
atio
n on
the
geom
orph
ic/p
hysi
ogra
phic
are
a of
the
Nep
al H
imal
aya.
15
Hag
en (1
969)
div
ided
Nep
al in
to
eigh
t phy
siog
raph
ic p
rovi
nces
fr
om so
uth
to n
orth
(as s
een
in
the
diag
ram
to th
e le
ft).
Each
pr
ovin
ce is
geo
grap
hica
lly
orie
nted
eas
t to
wes
t. W
hile
thi
s cla
ssifi
catio
n fit
s w
hat i
s reg
iona
lly o
bser
ved
thro
ugho
ut th
e H
imal
aya
it ch
arac
teris
tical
ly re
pres
ents
the
geom
orph
ic /
phys
iogr
aphi
c zo
nes o
f Nep
al.
Sour
ce: M
ap p
rese
nted
at h
ttp://
ww
w.ra
njan
.net
.np/
geol
ogy_
of_n
epal
/geo
logy
_of_
nepa
l.htm
and
refe
renc
ed it
s sou
rces
as,
Hag
en, T
., 19
69, R
epor
t on
the
geol
ogic
al su
rvey
of N
epal
pre
limin
ary
reco
nnai
ssan
ce: Z
üric
h, M
émoi
res d
e la
soc.
Hel
vétiq
ue d
es sc
i. na
ture
lles,
185
p.
Gen
eral
ized
Geo
mor
phic
- Ph
ysio
grap
hic
Prof
ile
the
Nep
al H
imal
aya
16
Som
e ge
olog
ists
(and
ge
ogra
pher
s) p
refe
r usi
ng a
5-
zone
cla
ssifi
catio
n sc
hem
e th
at
incl
udes
Ter
ai, C
hura
i, M
iddl
e M
ount
ain,
Hig
h M
ount
ain
and
Hig
h H
imal
aya.
How
ever
, on
the
next
slid
e I p
rese
nt a
de
scrip
tivel
y si
mila
r but
mod
ified
ve
rsio
n of
that
pre
pare
d by
Upr
eti
(199
9). I
als
o in
clud
e 8
geom
orph
ic z
ones
(phy
siog
raph
ic
prov
ince
s) in
the
next
slid
e’s
tabl
e.
Sour
ce: D
iagr
am p
rese
nted
at h
ttp://
ww
w.ra
njan
.net
.np/
geol
ogy_
of_n
epal
/geo
logy
_of_
nepa
l.htm
and
refe
renc
ed it
s’ so
urce
s as,
Daha
l, R.
, K.,
2006
, Geo
logy
for T
echn
ical S
tude
nts,
Bhr
ikut
i Aca
dem
ic P
ublic
atio
ns, K
athm
andu
, Nep
al, 7
46p.
.
Gen
eral
ized
Geo
logi
cal C
ross
- sec
tion
Nep
al H
imal
aya
17
Geo
mor
phog
ical
Div
isio
n of
the
Nep
al H
imal
aya
(mod
ified
afte
r Upr
eti,
1999
)
Ref:
Upr
eti,
1999
, An
over
view
of t
he st
ratig
raph
y and
tect
onic
s of t
he N
epal
Him
alay
a, J
ourn
al o
f Asi
an E
arth
Sci
ence
s 17
(199
9) p
p. 5
77- 6
06
18
¾Th
e K
ingd
om o
f Nep
al o
ccup
ies t
he c
entra
l sec
tor,
near
ly o
ne th
ird, o
f the
240
0 km
long
H
imal
ayan
Mou
ntai
n ra
nge.
¾Th
e re
gion
was
form
ed a
ppro
xim
atel
y 55
mill
ion
year
s ago
whe
n th
e In
dia
Plat
e co
llide
d w
ith th
e Eu
rasi
an P
late
. Th
is c
ollis
ion
is st
ill v
ery
activ
e to
day.
¾A
lthou
gh, t
he p
rimar
y m
echa
nism
of e
arth
quak
e ge
nera
tion
is th
rust
faul
ting
due
to
colli
sion
of b
oth
cont
inen
tal l
and
mas
ses,
othe
r cau
ses e
xist
for e
arth
quak
es o
ccur
ring
in
Nep
al.
¾N
epal
is lo
cate
d w
ithin
a v
ery
activ
e te
cton
ic re
gion
that
freq
uent
ly e
xper
ienc
es
earth
quak
es o
f mag
nitu
de ≥
4.
In S
umm
ary:
2004
pho
to m
osai
c th
e H
imal
ayas
with
Mak
alu
and
Mou
nt E
vere
st ta
kenf
rom
the
Inte
rnat
iona
l Spa
ce S
tatio
n: E
xped
ition
8
19