Body Wave Magnitude and Source Mechanism

1968 ◽  
Author(s):  
H. S. Jarosch
Keyword(s):  
Body Wave ◽  
Source Mechanism ◽  
Body Wave Magnitude

scholarly journals Analysis of Tsunami Inundation due in Pangandaran Tsunami Earthquake in South Java Area Based on Finite Faults Solutions Model

2020 ◽  
Vol 10 (2) ◽  
pp. 114
Author(s):  
Ramadhan Priadi ◽  
Dede Yunus ◽  
Berlian Yonanda ◽  
Relly Margiono
Keyword(s):  
Fault Plane ◽  
Body Wave ◽  
Scaling Law ◽  
Source Mechanism ◽  
Inversion Method ◽  
Tsunami Modeling ◽  
Residential Areas ◽  
North West ◽  
Wave Inversion ◽  
Run Up

On July 17, 2006 an earthquake with a magnitude of  7.7 triggered a tsunami that struck 500 km of the coast in the south of the island of Java. The tsunami generated is classified as an earthquake tsunami because the waves generated were quite large compared to the strength of the earthquake. The difference in the strength of the earthquake and the resulting tsunami requires a tsunami modeling study with an estimated fault area in addition to using aftershock and scaling law. The purpose of this study is to validate tsunamis that occur based on the estimation of the source mechanism and the area of earthquake faults. Determination of earthquake source mechanism parameters using the Teleseismic Body-Wave Inversion method that uses teleseismic waveforms with the distance recorded waveform from the source between  Whereas, tsunami modeling is carried out using the Community Model Interface for Tsunami (commit) method. Fault plane parameters that obtained were strike , dip , and rake  with dominant slip pointing up to north-north-west with a maximum value of 1.7 m. The fault plane is estimated to have a length of 280 km in the strike direction and a width of 102 km in the dip direction. From the results of the tsunami modeling, the maximum inundation area is 0.32 km2 in residential areas flanked by Pangandaran bays and the maximum run-up of 380.96 cm in Pasir Putih beach area. The tsunami modeling results in much smaller inundation and run-up from field observations, it was assumed that the fault plane segmentation had occurred due to the greater energy released than the one from the fault area, causing waves much larger than the modeling results.

The relationship between teleseismic body-wave magnitude m and local magnitude ML from New Zealand earthquakes

1972 ◽  
Vol 62 (1) ◽  
pp. 1-11
Author(s):  
S. J. Gibowicz
Keyword(s):  
New Zealand ◽  
Linear Relationship ◽  
Body Wave ◽  
Local Magnitude ◽  
The Relationship ◽  
Shallow Focus ◽  
Body Wave Magnitude

Abstract Relationships between the magnitudes ML and m for 123 New Zealand earthquakes occurring between 1950 and 1967 and having 4.6 ≦ ML ≦ 7.3 have been found. Deep- and shallow-focus shocks were considered separately. There is a linear relationship between ML and m, the slope being the same for both deep and shallow events. Values of ML for deep events are consistently 0.5 magnitude larger than those for shallow events having the same value of m. The relationship between m and ML for New Zealand earthquakes differs significantly from that obtained by Gutenberg and Richter in California.

Integrated and frequency-band magnitude, two alternative measures of the size of an earthquake

1970 ◽  
Vol 60 (3) ◽  
pp. 917-937 ◽  
Author(s):  
B. F. Howell ◽  
G. M. Lundquist ◽  
S. K. Yiu
Keyword(s):  
Transfer Function ◽  
Frequency Domain ◽  
Frequency Band ◽  
Transfer Functions ◽  
Body Wave ◽  
Average Amplitude ◽  
Equivalent Quantity ◽  
Short Period ◽  
Alternative Measures ◽  
Body Wave Magnitude

Abstract Integrated magnitude substitutes the r.m.s. average amplitude over a pre-selected interval for the peak amplitude in the conventional body-wave magnitude formula. Frequency-band magnitude uses an equivalent quantity in the frequency domain. Integrated magnitude exhibits less scatter than conventional body-wave magnitude for short-period seismograms. Frequency-band magnitude exhibits less scatter than body-wave magnitude or integrated magnitude for both long- and short-period seismograms. The scatter of frequency-band magnitude is probably due to real azimuthal effects, crustal-transfer-function variations, errors in compensation for seismograph response, microseismic moise and uncertainties in the compensation for attenuation with distance. To observe azimuthal variations clearly, the crustal-transfer functions and seismograph response need to be known more precisely than was the case in this experiment, because these two sources of scatter can be large enough to explain all of the observed variations.

Systematic difference in the ISC body-wave magnitude-seismic moment relationship between intermediate and deep earthquakes

1992 ◽  
Vol 82 (2) ◽  
pp. 819-835
Author(s):  
Keiko Kuge
Keyword(s):  
Seismic Moment ◽  
Body Wave ◽  
Systematic Difference ◽  
P Wave ◽  
Local Structures ◽  
Dependent Relationship ◽  
Deep Earthquakes ◽  
Amplitude Data ◽  
Body Wave Magnitude ◽  
Distance Correction

Abstract There exists a systematic difference in the ISC body-wave magnitude (mbISC) - seismic moment (M0) relationship between intermediate and deep earthquakes around Japan. For earthquakes with the same M0, the mbISC for intermediate events is larger than that for deep events by 0.2 to 0.3 units. The mbISC discrepancy is attributed to the depth-distance correction in the procedure for determining the mbISC; a larger depth-distance correction (≈ 0.2) is made for the intermediate events than the deep events, irrespective of station distance. The discrepancy disappears if no depth-distance correction is made. I observe no depth-dependent relationship between the M0 and the JMA magnitudes (MJMA), which make a different depth-distance correction. No significant depth-dependent mbISC discrepancy appears in other regions; for example, around Tonga, I observe larger ISC P-wave amplitudes from deep events than intermediate events, which could cancel the effect of the depth-distance correction. The depth-dependent mbISC - M0 relationship around Japan is observed irrespective of whether the magnitudes are determined using the amplitude data at far or near stations, or whether stations are used in the dipping direction of the slab or not. The mbISC discrepancy for the same M0 cannot arise from local structures, radiation patterns, and station coverages. This is not attributable to the dataset of the M0 itself because no significant depth-dependent relationship between M0 and MJMA is observed.

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