Seismic waves that spread through the Earths deep interior: BANG! - - PowerPoint PPT Presentation

Seismic waves that spread through the Earth’s deep interior:

BANG! or QUAKE!

90º 60º 30º Seismic source MANTLE CORE T h r e e s t a t i

• n

s a t d i f f e r e n t d i s t a n c e s f r

• m

t h e s

• u

r c e CRUST (very thin)

90º 60º 30º

90º 60º 30º

90º 60º 30º The wavefront position is shown after it has been traveling for several minutes. It continues to travel throughout the Earth's interior, bouncing off the core, and bouncing off the Earth's surface.

120° 130° 140°E 30° 40° 50°N

Russia Japan China

INCN MDJ MAJO BJT SSE HIA

KSRS USK HIA MJAR

126° 128° 130°E 40° 42° 44°N 200 km

2006Oct09

MDJ

Chongjin Kimchaek

NIED seismic stations

Hi-net 750 KiK-net 700 K-NET 1000 F-net 70

120° 130° 140°E 30° 40° 50°N

Russia Japan China

INCN MDJ MAJO BJT SSE HIA

KSRS USK HIA MJAR

126° 128° 130°E 40° 42° 44°N 200 km

2006Oct09

MDJ

Chongjin Kimchaek

crust mantle

Source Station

Pn - wave path (travels mostly in the mantle)

crust mantle

Source Station

Pg - paths, in the crust, all with similar travel times

30 60 90 120 150 180

time (sec)

30 60 90 120 150 180

Nuclear Test

9.7 µ/s 2006/10/09 M ~4.0 373.1 km az= 6 baz=186

Pn Pg Pn Pg Sn

Lg

Earthquake

11 µ/s 2004/12/16 M 4.0 341.6 km az= 23 baz=204

Pn Pg Sn? Lg?

Explosion

0.19 µ/s 1998/08/19 M 1.9, 2 ton 289.1 km az= 14 baz=194

Vertical Records at MDJ (Mudanjiang, NE China) from the North Korean Nuclear Test on 10/09/2006, a Nearby Earthquake Occurred on 12/16/2004 and a Known Explosion on 08/19/1998

Rayleigh wave

10 20 30 40 50 60

time (sec)

Earthquake 01/09/92 M=3.1 D=125 km

CRNY 5.9 km/s 3.4 km/s 1-10 Hz 10-25 Hz

20 30 40 50 60 70

time (sec)

Single Explosion 09/17/88 D=149 km

MDV 1-10 10-25

P S P S P to S ratio is small for an earthquake P to S ratio is large for an explosion especially at high frequency especially at high frequency

• 1.0
• 0.8
• 0.6
• 0.4
• 0.2

0.0 0.2 0.4 0.6 0.8 1.0

Log10 (Pg/Lg), 3-Component

1 3 5 7 9 11 13 15

Frequency (Hz)

Nuclear test on 25 May 2009 Nuclear test on 9 Oct. 2006 Earthquakes Chemical Explosions

from Pasyanos and Walter (2009 GRL paper)

North Korean Nuclear Test Site & Seismographic Stations in the Region

124˚E 125˚E 126˚E 127˚E 128˚E 129˚E 130˚E 131˚E 132˚E 37˚N 38˚N 39˚N 40˚N 41˚N 42˚N 43˚N 44˚N 45˚N 100 200 300

km

2006 2009 2013 Kilju

KSRS USRK

INCN

MDJ

YABA DHAA CBAI THAA

1,5 2 3 4 6 7 8 9 10

CN2 VLA 200 km

Yellow Sea

East Sea

Japan Sea

North Korea South Korea China Russia

Kaesong Wonsan

Pyongyang

Seoul

Sinuiju Hamhung Chongjin Kimchaek Youngbyun

Nuclear tests Earthquakes Known explosions GSN stations IMS stations National stations

120˚E 130˚E 140˚E 40˚N 50˚N 500 km

Russia

Japan China

Korea

East Sea

Japan Sea INCN MDJ MAJO BJT HIA KSRS USRK HIA MJAR

40 60 80 100 120 140 160 180

time (sec)

40 60 80 100 120 140 160 180

Conducted in North Korea, 12 February 2013, 02:57:51.4, 41.301˚N, 129.066˚E

MDJ Vertical

94.2 µm/s

OT=02:57:51.4

2013-02-12 371.0 km az= 7˚ baz=187˚

Pn Pg Surface wave

MDJ N-S

70.3 µm/s

M 5.1, PDE 2013-02-12 MDJ E-W

59.3 µm/s

2013-02-12

Sn Lg

MDJ Vertical

37.8 µm/s

OT=00:54:43.3

2009-05-25 370.8 km az= 7˚ baz=187˚ MDJ N-S

28.4 µm/s

M 4.7, PDE 2009-05-25 MDJ E-W

23.6 µm/s

2009-05-25 MDJ Vertical

9.7 µm/s OT=01:35:28.0

2006-10-09 371.5 km az= 6˚ baz=186˚ MDJ N-S

8.2 µm/s

M 4.3 PDE 2006-10-09 MDJ E-W

6.7 µm/s

2006-10-09

3-Component Records at MDJ (Mudanjiang, China) from Three Nuclear Tests

Vienna, 15 February 2013 A total of 96 International Monitoring System (IMS) stations have now sent data related to the unusual seismic activity detected in North Korea on 12 February 2013 to the International Data Centre (IDC) in Vienna for

• analysis. The magnitude of the event has been

confirmed as 4.9 by the IDC. The analysed data have also enabled the error ellipse to be decreased, thus confirming the event’s location with a certainty of about +/- 8.1 km.