An episodic creep-slip event detected by precise levelling surveys in the central part of the Longitudinal Valley Fault, eastern Taiwan, in 2011–2012

2013 ◽  
Vol 608 ◽  
pp. 904-913 ◽  
Author(s):  
Masayuki Murase ◽  
Nobuhisa Matta ◽  
Cheng-Hong Lin ◽  
Wen-Shan Chen ◽  
Naoji Koizumi
2015 ◽  
Vol 41 (4) ◽  
pp. 145-155
Author(s):  
Timo Saari ◽  
Markku Poutanen ◽  
Veikko Saaranen ◽  
Harri Kaartinen ◽  
Antero Kukko ◽  
...  

Precise levelling is known for its accuracy and reliability in height determination, but the process itself is slow, laborious and expensive. We have started a project to study methods for height determination that could decrease the creation time of national height systems without losing the accuracy and reliability that is needed for them. In the pilot project described here, we study some of the alternative techniques with a pilot field test where we compared them with the precise levelling. The purpose of the test is not to evaluate the mutual superiority or suitability of the techniques, but to establish the background for a larger test and to find strong and weak points of each technique. The techniques chosen for this study were precise levelling, Mobile Laser Scanning (MLS) and Global Navigation Satellite System (GNSS) levelling, which included static Global Positioning System (GPS) and Virtual Reference Station (VRS) measurements. This research highlighted the differences of the studied techniques and gave insights about the framework and procedure for the later experiments. The research will continue in a larger scale, where the suitability of the techniques regarding the height systems is to be determined.


2020 ◽  
Author(s):  
Josué Tago ◽  
Víctor M. Cruz-Atienza ◽  
Carlos Villafuerte ◽  
Takuya Nishimura ◽  
Vladimir Kostoglodov ◽  
...  

1993 ◽  
Vol 98 (B9) ◽  
pp. 15797 ◽  
Author(s):  
Masayuki Kikuchi ◽  
Hiroo Kanamori ◽  
Kenji Satake
Keyword(s):  

1989 ◽  
Vol 79 (2) ◽  
pp. 500-514 ◽  
Author(s):  
Allison L. Bent ◽  
Donald V. Helmberger ◽  
Richard J. Stead ◽  
Phyllis Ho-Liu

Abstract Long-period body-wave data recorded at teleseismic distances and strong-motion data at Pasadena for the Superstition Hills earthquakes of 24 November 1987 are modeled to obtain the source parameters. We will refer to the event that occurred at 0153 UT as EQ1 and the event at 1316 UT as EQ2. At all distances the first earthquake appears to be a simple left-lateral strike-slip event on a fault striking NE. It is a relatively deep event with a source depth of 10 km. It has a teleseismic moment of 2.7 ×1025 dyne cm. The second and more complex event was modeled in two ways: by using EQ1 as the Green's function and by using a more traditional forward modeling technique to create synthetic seismograms. The first method indicated that EQ2 was a double event with both subevents similar, but not identical to EQ1 and separated by about 7.5 sec. From the synthetic seismogram study we obtained a strike of 305° for the first subevent and 320° for the second. Both have dips of 80° and rakes of 175°. The first subevent has a moment of 3.6 ×1025 which is half that of the second. We obtain depths of at least 6 km. The teleseismic data indicate a preferred subevent separation of 30 km with the second almost due south of the first, but the error bounds are substantial. This would suggest that the subevents occurred on conjugate faults. The strong-motion data at PAS, however, imply a much smaller source separation, with the sources probably produced by asperities.


2021 ◽  
Author(s):  
Leonard Seydoux ◽  
Michel Campillo ◽  
René Steinmann ◽  
Randall Balestriero ◽  
Maarten de Hoop

<p>Slow slip events are observed in geodetic data, and are occasionally associated with seismic signatures such as slow earthquakes (low-frequency earthquakes, tectonic tremors). In particular, it was shown that swarms of slow earthquake can correlate with slow slip events occurrence, and allowed to reveal the intermittent behavior of several slow slip events. This observation was possible thanks to detailed analysis of slow earthquakes catalogs and continuous geodetic data, but in every case, was limited to particular classes of seismic signatures. In the present study, we propose to infer the classes of seismic signals that best correlate with the observed geodetic data, including the slow slip event. We use a scattering network (a neural network with wavelet filters) in order to find meaningful signal features, and apply a hierarchical clustering algorithm in order to infer classes of seismic signal. We then apply a regression algorithm in order to predict the geodetic data, including slow slip events, from the occurrence of inferred seismic classes. This allow to (1) identify seismic signatures associated with the slow slip events as well as (2) infer the the contribution of each classes to the overall displacement observed in the geodetic data. We illustrate our strategy by revisiting the slow-slip event of 2006 that occurred beneath Guerrero, Mexico.</p>


1999 ◽  
Vol 89 (4) ◽  
pp. 1077-1082 ◽  
Author(s):  
So Gu Kim ◽  
Nadeja Kraeva

Abstract The purpose of this investigation is to determine source parameters such as focal mechanism, seismic moment, moment magnitude, and source depth from recent small earthquakes in the Korcan Peninsula using broadband records of three-component single station. It is very important and worthwhile to use a three-component single station in Korea because for most Korean earthquakes it is not possible to read enough first motions of P-wave arrivals because of the poor coverage of the seismic network and the small size (ML 5.0 or less) of the events. Furthermore the recent installation of the very broadband seismic stations in Korea and use of a 3D tomography technique can enhance moment tensor inversion to determine the source parameters of small earthquakes (ML 5.0 or less) that occur at near-regional distances (Δ ≤ 500 km). The focal solution for the Youngwol earthquake of 13 December 1996 is found to be a right-lateral strike slip event with a NE strike, and the Kyongju earthquake of 25 June 1997 is found to be an oblique reverse fault with a slight component of left-lateral slip in the SE direction.


Sign in / Sign up

Export Citation Format

Share Document