蒲新杰 92642006@cc.ncu.tw

觀測地震學實習Exercise of Observation Seismology 1. 識別 P- 和 S- 波 1. Determine P and S wave

2. 地震定位 2. earthquake locating

蒲新杰92642006@cc.ncu.edu.tw

實習 Exercise

• Laboratory : S319.• Platform : Linux.• User/password : GP6049/student62057• Picking : SAC (Seismic Analysis Code).• Location : Hypo 71.• Time : ??

地震定位 - 震波訊號Earthquake Locating –Seismic

Record•測站的資訊( 地震波訊號 ) Seismic record of each station 定位程式 + 速度模型location program+ velocity structure 震源參數( 位置規模 )Parameter of hypocenter (location & magnitude)•單站資料 single station

•多站資料 multiple stations

Introduction to SeismologyPeter M. Shearer, 1999

Surface

3-component seismograms

I/E0-4U/DP

I/E0-4SpaceS F

PPK

• N: next plot• B: previous plot• X: Zoom in• O: previous plot window (Zoom out)• H: Write picks to HYPO pick file.

定位程式 Earthquake Locating Program

• 1. IRIS• Platform : Windows.• Method : Trial and error.• H.W.: Seismic waveform (CWBSN).• Note : 取 Z 方向資料 , 最多 10筆資料 . Take data of Z component, no more than ten. 課程流水號 (解壓縮密碼 ) ： 62060 Course Number (unzip password) :62060• 2. Hypo71• Platform : Unix & Windows.• Method : Inversion.• H.W.: Seismic waveform (CWBSN).

Hypo 71

iii tTR

極小化 (minimize) ei

iiii

i edzztdy

ytdx

xtdtR

Geiger’s method, 1912

• input ： 1. P-and/or S-waves 到時 arrival time. 2. 速度模型和測站坐標 . velocity structure and coordinates of earthquake stations.

• output：發震時間、震源位置、規模、時間殘差、震源誤差、定位品質等。hypocenter time, hypocenter location, magnitude, Residual

time RMS, standard error of the epicenter in km at Horizontal and Vertical , Quality, ….

速度模型和測站坐標velocity structure and coordinate of earthquake station

計算地震規模 (MD) ，其經驗公式為：Calculated duration magnitude(MD):

MD = -0.87 + 2.0 log + 0.0035

式中為總振動時間（以秒為單位），為測震站到震央的距離（以公里為單位）。Which : total shaking duration (sec.), :distance from station to epicenter (km)

Output-file decode

DATE

ORIGIN

LAT-N

LONG-

E

DEPTH

MAG

NO

GAP

DMIN

RMS

ERH

ERZ

QM

2001/12/01

00/39/23.63

22-25.66

120-31.44

24.78 2.12 35 261 9.8 0.26 1.8 1.1 C1

QS RMS ( sec ) ERH ( km ) ERZ ( km )

A LT. 0.15 LE. 1.0 LE. 2.0

B LT. 0.30 LE. 2.5 LE. 5.0

C LT. 0.50 LE. 5.0

D Others

QD NO ( P+S ) GAP DMIN

A GE. 6 LE. 90 LE. Depth or 5 km

B GE. 6 LE. 135 LE. 2*Depth or 10 km

C GE. 6 LE. 180 LE. 50 km

D Others

Q Epicenter Focal Depth

A Excellent Good

B Good Fair

C Fair Poor

D Poor Poor

觀測波形Observation waveform

挑選初達 P 和 S 波Picking first arrival P and S

Hypo71

決定震源位置及發震時間Calculated hypocenter location and

time

流程圖 Flowchart

速度模型、測站坐標及參數設定Velocity structure, Station location

and Parameters