Benefits of Defining Geological Sensitive Zones in the Mitigation of Disasters Along Earthquake Fault Zones in Taiwan – The Case of Milun Fault

In Taiwan, the main purpose of earthquake fault zone legislation is to prevent earthquake-related disasters around the surface traces of active faults, particularly in urban areas. Here, the Geologically Sensitive Area (GSA) of the Milun Fault (Milun Earthquake Fault Zone) is used as an example to reveal the importance of such legislation. Field data collected along the Milun Fault before and after the 2018 Hualien Earthquake were used to reveal the reappearance of damages within the GSA. The 2018 Hualien Earthquake represents one of the shortest recurrence intervals (67 years) among all major faults in Taiwan. Most of the surface ruptures and damaged buildings in Hualien City were within the Milun Fault GSA and concentrated on the hanging wall of the fault. Moreover, 61% (91/148) of the damaged buildings and 83% (692/835) of the surface ruptures occurred within 100 m of the fault line. The results of this study demonstrate the importance of defining GSAs of active faults for mitigating earthquake hazards.

Active Fault Systems in the Inner Northwest Apennines, Italy: A Reappraisal One Century after the 1920 Mw ~6.5 Fivizzano Earthquake

Based on the review of the available stratigraphic, tectonic, morphological, geodetic, and seismological data, along with new structural observations, we present a reappraisal of the potential seismogenic faults and fault systems in the inner northwest Apennines, Italy, which was the site, one century ago, of the devastating Mw ~6.5, 1920 Fivizzano earthquake. Our updated fault catalog provides the fault locations, as well as the description of their architecture, large-scale segmentation, cumulative displacements, evidence for recent to present activity, and long-term slip rates. Our work documents that a dense network of active faults, and thus potential earthquake fault sources, exists in the region. We discuss the seismogenic potential of these faults, and propose a general tectonic scenario that might account for their development.

Analisis Riwayat Waktu Gempa Sesar pada Sistem Fondasi Tiang

In Indonesia, many active faults that can cause earthquakes, one of them is the Palu Koro fault which extends approximately 240 km from the north (Palu City) to the south (Malili) to the Gulf of Bone. The effect of this earthquake fault caused enormous damage to infrastructure. The lower structure, namely the foundation, is part of a structure that transmits the load received from axial and lateral forces which then continues into the ground below. This foundation plays a big role in making the structure stand firm; however, pile failures still often occur in Indonesia. Because of that in this journal will be analyzing of the time history of earthquake faults in the pile foundation system. This analysis requires the assistance of a geotechnical based program. The program can process the data provided so that it produces a result that can be analyzed. The results can be in the form of internal forces, and displacement. The result of this curve we can see the effect of the earthquake fault on the foundation. From these results, it is expected to provide data to help plan structures to be built in areas prone to earthquake faults.AbstrakWilayah Indonesia banyak terdapat sesar aktif yang dapat menimbulkan gempa salah satunya sesar aktif di Sulawesi adalah sesar Palu Koro yang memanjang kurang lebih 240 km dari utara (Kota Palu) ke selatan (Malili) hingga Teluk Bone. Pengaruh gempa sesar ini menimbulkan kerusakan yang sangat besar dalam infrastruktur. Struktur bawah yakni Fondasi ialah bagian dari suatu struktur yang meneruskan beban yang diterima dari gaya aksial dan lateral yang kemudian meneruskan ke dalam tanah di bawahnya. Fondasi inilah berperan besar membuat struktur tersebut dapat berdiri kukuh akan tetapi kegagalan tiang masih sering terjadi di Indonesia. Dengan demikian pada jurnal ini dilakukan analisis riwayat waktu gempa sesar pada sistem fondasi tiang. Analisis ini membutuhkan bantuan program berbasis geoteknik. Program dapat mengolah data-data yang diberikan sehingga menghasilkan suatu hasil yang dapat di analisis. Hasil tersebut dapat berupa kurva gaya dalam dan perpindahan. Hasil dari kurva ini kita dapat melihat pengaruh dari gempa sesar tersebut terhadap fondasi. Dari hasil tersebut diharapkan dapat memberikan data-data untuk membantu merencanakan bangunan struktur yang akan dibangun di wilayah yang rawan akan gempa sesar.

A comparison of alternative curve fitting techniques for different earthquake fault parameters of Iranian earthquakes

In this study, we tried to estimate the optimum linear equations among the parameters associated with different earthquake fault mechanisms for Iranian earthquakes. For this purpose, we tested different curve fitting methods in order to present the most proper empirical relationships between several seismic parameters for different fault systems. In the present paper, 46 large and destructive Iranian earthquakes whose magnitudes change between 5.8 and 7.8 from 1900 to 2014 were used for the analyses. A comparison was made by using four types of curve fitting techniques. The estimation procedures are considered as (1) L2 or Least Squares Regression, (2) L1 or Least Sum of Absolute Deviations Regression, (3) Robust Regression and, (4) Orthogonal Regression. Confidence intervals were selected as 95% for all types of regression relationships. In the selection of the best probability distribution, we considered the correlation coefficients of the linear regressions as a powerful and conceptually simple method. Correlation coefficients of all relationships change between 0.299 and 0.986 with Orthogonal regression, between 0.168 and 0.792 with L1 regression, between 0.059 and 0.829 with Robust regression. For Iranian earthquakes, the most suitable and reliable empirical relationships between moment magnitude (Mw) and surface wave magnitude (Ms), Mw and surface rupture length (SRL), Mw and maximum displacement (MD), and SRL and MD were obtained by Orthogonal regression since it supplies stronger correlation coefficients than those of the other regression techniques in most estimates. The results show that estimated empirical relationships among the different fault parameters by using the Orthogonal regression method can be accepted as more up-to-date and more appropriate in comparison with the other regression norms. Consequently, these equations were suggested as more reliable in the estimation of the maximum surface displacement, maximum surface rupture length and associated with the maximum credible earthquakes for different areas of Iran. Furthermore, obtained relationships can be statistically significant for the assessment of seismic, tectonic and geologic activities, and they can be used to evaluate the rupture hazard of the Iranian Plateau.

NEAR-FIELD TSUNAMI FORECASTING BASED ON A TSUNAMI RUN-UP RESPONSE FUNCTION

Since near-field-generated tsunamis can arrive within a few minutes to coastal communities and cause immense damage to life and property, tsunami forecasting systems should provide not only accurate but also rapid tsunami run-up estimates. For this reason, most of the tsunami forecasting systems rely on pre-computed databases, which can forecast tsunamis rapidly by selecting the most closely matched scenario from the databases. However, earthquakes not included in the database can occur, and the resulting error in the tsunami forecast may be large for these earthquakes. In this study, we present a new method that can forecast near-field tsunami run-up estimates for any combination of earthquake fault parameters on a real topography in near real-time, hereafter called the Tsunami Run-up Response Function (TRRF).Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/tw1D29dDxmY