Crustal velocity structure in Borneo Island using receiver function inversion

We analyze high-frequency receiver functions from two seismic stations to characterize the sediment properties around the eastern coast of Kalimantan. First, we compute high-frequency receiver functions from teleseismic events using the time-domain deconvolution method. The obtained receiver functions are then stacked using the H-κ stacking approach to determine the sediment properties. The computed receiver functions show the complicated waveforms for the seismic station located near Kutai Basin. These waveforms may indicate the presence of multi sedimentary layers. The H-κ stacking results suggest that the sediment is thinner in the northern part of the area (∼1.34 km depth) than in the southern part of the region (∼3.0 km depth). These results are consistent with the previous geological and geophysical studies conducted in this region. The previous works suggested that the sediment thickness around the study area can reach up to 9 km.

Section: Resultssupporting

confidence: 92%

Section: Resultsmentioning

confidence: 60%

Sediment thickness in the eastern part of Kalimantan from high-frequency receiver functions

Syuhada,

Pranata,

Anggono

et al. 2023

“…In this study, we characterize the crustal properties around the Meratus Complex Zone using the same teleseismic waveform dataset extracted by the previous study [8]. The teleseismic events used in this work have big enough magnitudes (>6) to ensure that the waveforms have a good signal-to-noise ratio.…”

Section: Methodsmentioning

confidence: 99%

“…The previous geophysical and geological studies conducted around the region are mainly focused on the shallow crustal structure. The recent seismological study [8] successfully reveals the crustal velocity structure of the area by inverting the time series receiver function. However, due to limited information about crustal properties around the region, another method is necessary to assess the consistency of the previous findings and to provide more constraints on the crustal structure information.…”

Section: Introductionmentioning

confidence: 99%

Crustal properties investigation in the Meratus Complex Zone, Southeast Borneo, using H-κ stacking of receiver function analysis

Syuhada,

Pranata,

Anggono

et al. 2023

We study crustal properties using teleseismic receiver functions extracted from two broadband seismic stations around the Meratus Complex region, Southeast Borneo. The two seismic stations, BBKI and KBKI, are distributed in the Meratus Mountains and Pulau Laut. We then employ the H-κ stacking technique to measure the crustal thickness (H) and the crustal average Vp/Vs ratio (κ). The method works quite well for receiver functions recorded on seismic station KBKI. The thickness of the crust and Vp/Vs ratio underneath this station are around 38 km and 1.64, respectively. On the contrary, the standard H-κ method fails in estimating the crustal properties beneath station BBKI due to significant sedimentary contamination on the receiver functions. Thus, we apply the sequential H-κ stacking analysis by removing the sedimentary effect and increasing the Moho Ps amplitude. The result shows the thickness of the crust is around 29 km, although the Vp/Vs is not well determined. The research findings from both stations are comparable to those derived from the previous receiver function study using inversion modelling. The crustal properties around this area may reflect the continental material part of the Sunda continental block.

“…The research area is included in the Kutai Basin, which has a thick layer of sediment with a thickness of > 3 km [13]. Physiographically, to the north of the Kutai Basin, it is bordered by Sangkulirang, the Bengalon Fault Zone, and the Mangkalihat High.…”

Section: Geological Settingmentioning

confidence: 99%

Preliminary result of dominant frequency and seismic amplification in Penajam Paser Utara and its surrounding regions using the HVSR method

Mawadah,

Zulfakriza,

Widiyantoro

et al. 2023

East Kalimantan has been designated as the new capital city of Indonesia, precisely in Penajam Paser Utara and Kutai Kartanegara Regency. According to the historical records of seismic activity, there were several destructive earthquakes in East Kalimantan. Therefore, it is necessary to study the characteristics of the local site to assess the seismic hazard potential in the new capital city area and its surroundings. In this research, the Horizontal to Vertical Spectral Ratio (HVSR) method was applied by utilizing microtremor data from 21 seismometers installed in the research area. The results of the HVSR analysis obtained the dominant frequency (f0) and amplification factor (A0) from the H/V curve. Based on the H/V calculation, the highest f0 is 13.04 Hz and the lowest value is 0.58 Hz. Meanwhile, the highest value for A0 is 6.41, and the lowest value is 1.41. The results of the study show that the research area has a low to medium level of seismic hazard.