5 May 2014 MW 6.1 Mae Lao (Northern Thailand) Earthquake: Interpretations of Recorded Ground Motion and Structural Damage

2016 ◽  
Vol 32 (2) ◽  
pp. 1209-1238 ◽  
Author(s):  
Teraphan Ornthammarath ◽  
Pennung Warnitchai
Keyword(s):  
Structural Damage ◽  
Shear Failure ◽  
Main Shock ◽  
Ground Motions ◽  
Strong Motion ◽  
Earthquake Catalog ◽  
Northern Thailand ◽  
Epicentral Area ◽  
Soft Story ◽  
The Town

A moderate left-lateral strike-slip earthquake of MW 6.1 occurred on 5 May 2014 in northern Thailand, causing damage to the town of Mae Lao and nearby municipalities. Based on an instrumental earthquake catalog, the Mae Lao earthquake is the second largest earthquake in modern Thai history after the MW 6.3 Nan earthquake in 1935. In this study, the strong-motion records from the epicentral area are analyzed in order to investigate the characteristics of the ground motions. In addition, post-earthquake field observations and statistics for typical structural damage in the affected area, such as the soft story effect and the shear failure of columns, are summarized. Besides major structural damage, the majority of structures in the epicentral area withstood the strong motion, which could be due to the low stress drop of the main shock (40 bars) leading to below average ground motions for an MW 6.1 earthquake.

scholarly journals Observations and Simulations of Basin Effects in the Kathmandu Valley during the 2015 Gorkha, Nepal, Earthquake Sequence

2017 ◽  
Vol 33 (1_suppl) ◽  
pp. 35-53 ◽  
Author(s):  
Domniki Asimaki ◽  
Kami Mohammadi ◽  
Henry B. Mason ◽  
Rachel K. Adams ◽  
Sudhir Rajaure ◽  
...  
Keyword(s):  
Structural Damage ◽  
Main Shock ◽  
Ground Motions ◽  
Strong Motion ◽  
Lateral Spreading ◽  
Unconsolidated Sediments ◽  
Kathmandu Valley ◽  
Motion Data ◽  
Basin Effects ◽  
Shed Light

The M7.8 Gorkha, Nepal main shock ruptured a segment of the Main Himalayan Thrust (MHT) directly below Kathmandu Valley, causing strong shaking levels across the valley. Strong-motion data reveal an initial 6 s source pulse that was amplified and reverberated within the basin. One of the striking features of the observed ground motions in the valley was the exceptionally low energy of periods less than 2 s, which likely limited the extent and severity of structural damage in Kathmandu compared with alternative rupture scenarios of the same magnitude in the region. Isolated cases of liquefaction and lateral spreading of unconsolidated sediments were also observed, but have not yet revealed a systematic damage pattern. Initial analysis of available data suggests that several different factors, including source and path as well as site effects, were responsible for the unusual ground motions characteristics. In this paper, we provide a short description of the Kathmandu Valley geology and analyze available strong-motion records from the main shock and three strong aftershocks, with the intent to shed light on earthquake reconnaissance observations from this earthquake.

The island of Hawaii earthquakes of November 29, 1975: Strong-motion data and damage reconnaissance report

1977 ◽  
Vol 67 (2) ◽  
pp. 493-515
Author(s):  
Christopher Rojahn ◽  
B. J. Morrill
Keyword(s):  
Local Time ◽  
Structural Damage ◽  
Strong Motion ◽  
Maximum Acceleration ◽  
Epicentral Area ◽  
Ground Shaking ◽  
Motion Data ◽  
Large Sector ◽  
Threshold Duration ◽  
Strong Ground

Abstract Two earthquakes occurred on the island of Hawaii on November 29, 1975, a magnitude (Ms) 5.7 event at 0335 (local time) and a magnitude (Ms) 7.2 event at 0447. During the larger event, a maximum acceleration of 0.22 g was recorded in the southern part of Hilo, 43 km north of the epicenter. A 0.05 g threshold duration of 13.7 sec was measured for the same component. Smaller amplitude accelerograph records were obtained at two other locations on the island along with four seismoscope records. During or subsequent to the larger event, a large sector of the southeastern coastline subsided by as much as 3.5 meters. A tsunami generated by the larger event caused at least one death (one person also missing), injury to 28 persons, and significant structural and nonstructural damage. Only scattered evidence of strong ground shaking was observed in the epicentral area, and most of the several dozen nearby structures sustained little or no structural damage from ground shaking. In Hilo, 45 km north of the Ms = 7.2 epicenter, structural and nonstructural damage was slight to moderate but more extensive than elsewhere on the island.

The 23 October 2011 MW7.0 Van (Eastern Turkey) Earthquake: Interpretations of Recorded Strong Ground Motions and Post-Earthquake Conditions of Nearby Structures

2014 ◽  
Vol 30 (2) ◽  
pp. 657-682 ◽  
Author(s):  
V. Akansel ◽  
G. Ameri ◽  
A. Askan ◽  
A. Caner ◽  
B. Erdil ◽  
...  
Keyword(s):  
Fault Plane ◽  
Ground Motions ◽  
Hanging Wall ◽  
Strong Motion ◽  
Thrust Fault ◽  
Building Structures ◽  
Epicentral Area ◽  
Historical Structures ◽  
Strict Compliance ◽  
Strong Ground

A major thrust-fault earthquake of MW = 7.0 occurred on 23 October 2011 at 10:41:21 UTC in the eastern Anatolian region of Turkey, severely affecting the nearby towns of Van and Erciş. In this study, a few strong-motion records from the epicentral area are analyzed in order to investigate the characteristics of the ground motions. Also reported are the post-earthquake field observations for various types of structures, such as buildings, bridges, historical structures, tunnels, and dams within the vicinity of the fault plane. The spatial distribution of damage indicates a noticeable hanging-wall effect. The special-type structures are observed to experience far less damage, as opposed to the building structures in the region pointing to the need for strict compliance to seismic building code and the corresponding construction requirements.

scholarly journals Seismicity anomalies prior to 8 June 2008, <i>M<sub>w</sub></i>=6.4 earthquake in Western Greece

2009 ◽  
Vol 9 (2) ◽  
pp. 327-335 ◽  
Author(s):  
G. Chouliaras
Keyword(s):  
Main Shock ◽  
Earthquake Catalog ◽  
Large Area ◽  
Data Set ◽  
Epicentral Area ◽  
Seismicity Rate ◽  
Seismicity Pattern ◽  
Scientific Investigations ◽  
Seismological Data ◽  
Western Greece

Abstract. The epicentral area of the Mw=6.4, 8 June 2008 main shock in northwestern Peloponesus, Western Greece, had been forecasted as a candidate for the occurrence of a strong earthquake by independent scientific investigations. This study concerns the seismicity of a large area surrounding the epicenter of the main shock using the seismological data from the monthly bulletins of the Institute of Geodynamics of the National Observatory of Athens. This data set is the most detailed earthquake catalog available for anomalous seismicity pattern investigations in Greece. The results indicate a decrease in seismicity rate seven years prior to the 8 June main shock which constituted a two and a half year long seismic quiescence surrounding the epicentral area. This quiescence anomaly was succeeded by a period of acceleration in seismic activity for five years approximately, until the occurrence of the main shock.

Near-Field Ground Motions and Shaking from the 2019 Mw 7.1 Ridgecrest, California, Mainshock: Insights from Instrumental, Macroseismic Intensity, and Remote-Sensing Data

2020 ◽  
Vol 110 (4) ◽  
pp. 1506-1516 ◽  
Author(s):  
Susan E. Hough ◽  
Sang-Ho Yun ◽  
Jungkyo Jung ◽  
Eric Thompson ◽  
Grace A. Parker ◽  
...  
Keyword(s):  
Ground Motion ◽  
Structural Damage ◽  
Ground Motions ◽  
Near Field ◽  
Remote Sensing Data ◽  
Prediction Equation ◽  
Intensity Data ◽  
Radar Images ◽  
Conversion Equation ◽  
The Town

ABSTRACT Shaking from the 6 July 2019 Mw 7.1 Ridgecrest, California, mainshock was strongly felt through southern California, but generated relatively minimal structural damage in Ridgecrest. We consider the extent to which a damage proxy map (DPM) generated from satellite-based Synthetic Aperture Radar images can detect minor damage throughout the town of Ridgecrest. The DPM does not, as expected, detect all minor structural damage to individual structures, nor can it distinguish between structural damage and earthquake-related movement that is not consequential. However, the DPM does confirm many instances of minor structural damage to larger structures and groups of smaller structures and in some instances suggests minor structural damage that is not apparent upon visual inspection. Although ambiguous identification of minor damage may not be useful to guide earthquake response, the identification of minor, possibly hidden damage is potentially useful for other purposes. Overall, the DPM confirms that structural damage was commensurate with modified Mercalli intensity no higher than 7 throughout Ridgecrest. We consider both instrumental and intensity data to explore further the distribution of near-field ground motions over the frequency range of engineering concern. Peak ground accelerations and peak ground velocities estimated from “Did You Feel It?” intensity data using the Worden et al. (2012) ground-motion intensity conversion equation (GMICE) are consistent with recorded instrumental data. Both instrumental and estimated mainshock peak accelerations are further consistent with predictions from both the Boore et al. (2014) ground-motion prediction equation (GMPE), but lower than predicted by the Atkinson and Wald (2007) and Atkinson et al. (2014) intensity prediction equations (IPEs). A GMPE such as Boore et al. (2014), which is constrained by a large global dataset, together with a well-constrained GMICE, may thus characterize expected shaking intensities for large earthquakes better than an IPE based on more limited intensity data.

Overview of strong-motion data from the Darfield earthquake

2010 ◽  
Vol 43 (4) ◽  
pp. 222-227 ◽  
Author(s):  
Jim Cousins ◽  
Graeme H. McVerry
Keyword(s):  
Main Shock ◽  
Ground Motions ◽  
Strong Motion ◽  
Vertical Acceleration ◽  
Strong Motion Data ◽  
Motion Data ◽  
Near Fault ◽  
Long Period ◽  
Fault Record ◽  
Stiff Soil

The Darfield earthquake of 3rd September 2010 UT and its aftershocks have yielded New Zealand’s richest set of strong-motion data since recording began in the early 1960s. Main-shock accelerograms were returned by 130 sites, ten of which had peak horizontal accelerations in the range 0.3 to 0.82g. One near-fault record, from Greendale, had a peak vertical acceleration of 1.26g. Eighteen records showed peak ground velocities exceeding 0.5 m/s, with three of them exceeding 1 m/s. The records included some with strong long-period directivity pulses, some with other long-period components that were related to a mixture of source and site effects, and some that exhibited the effects of liquefaction at their sites. There were marked differences between records on the deep alluvium of Christchurch City and the Canterbury Plains, and those on shallow stiff soil sites. The strong-motion records provide the opportunity to assess the effects of the earthquake in terms of the ground motions and their relationship to design motions. They also provide an invaluable set of near-source motions for seismological studies. Our report presents an overview of the records and some preliminary findings derived from them.

scholarly journals The Mw 6.6 Gisborne earthquake of 2007

2008 ◽  
Vol 41 (4) ◽  
pp. 266-277 ◽  
Author(s):  
Caroline François-Holden ◽  
Stephen Bannister ◽  
John Beavan ◽  
Jim Cousins ◽  
Bryan Field ◽  
...  
Keyword(s):  
Structural Damage ◽  
Main Shock ◽  
Fault Plane ◽  
Moment Tensor ◽  
High Stress ◽  
Strong Motion ◽  
Slow Slip ◽  
Plate Interface ◽  
Direction Parallel ◽  
Moment Tensor Solution

Gisborne city experienced recorded peak ground accelerations exceeding 0.25g for the third time since 1966 in the magnitude Mw 6.6 earthquake at 075516 UT (8:55 pm local time) on 20 December 2007. The earthquake was at a hypocentral distance of 64 km from Gisborne at a depth of 40 km, well within the mantle of the subducted slab of the Pacific plate as it dips beneath the North Island of New Zealand. At this location the plate interface is about 10-15 km deep. The main event was followed by sparse aftershocks consistent with a rupture of the subducted plate, with the largest aftershock of magnitude 4.6 occurring on December 22nd. The GeoNet website received 3,257 felt reports, with a strongest intensity of MM8 (heavily damaging) assigned to the main shock. The 122 strong motion records of this event show a clear regional directional variation in the wave propagation, as well as a distinct 2 Hz peak widely observed throughout the country. At a local scale, three sites in the Gisborne region recorded accelerations around 0.2g. Recordings in Gisborne city also revealed a predominant displacement direction, parallel to the main street where most of the damage occurred. Source studies from moment tensor solution, aftershock relocations, GPS and strong motion data showed that the earthquake occurred within the subducted plate on a 45 degree eastward dipping fault plane. The mainshock rupture area is about 10 km2 reaching a maximum slip of 2.6 m. The computed high stress drop value of 17 MPa is as expected for an intraslab event and consistent with observations of very energetic seismic waves as well as heavy structural damage. GPS data recorded by continuous GPS instruments have also shown that slow slip occurred for about three weeks after the main shock. The slow slip was triggered on the subduction interface, rather than on the same fault plane as the aftershocks. This is the first clear-cut case worldwide of triggered slow slip, although three non-triggered slow-slip events have occurred in the same region since 2002.

Edgecombe earthquake

1987 ◽  
Vol 20 (3) ◽  
pp. 201-249 ◽  
Author(s):  
M. J. Pender ◽  
T. W. Robertson
Keyword(s):  
Structural Damage ◽  
Ground Surface ◽  
Strong Motion ◽  
Normal Fault ◽  
Lateral Spreading ◽  
Ground Acceleration ◽  
Paper Mills ◽  
North West ◽  
The North ◽  
The Town

On March 2 1987, at 01h 42m 34s UT an earthquake of magnitude (ML) 6.3 occurred near 37.91°S, 176.79°E close to the town of Edgecumbe in the North Island, New Zealand. The depth is provisionally estimated to be 12 ± 1 km. Seismic activity in the general area during the previous week culminated in a foreshock on March 2 of ML 5.2 at 01h 35m 37s. Four aftershocks with magnitudes in excess of 5.0 occurred on March 2 at 01h 51m 08s (ML 5.6), 02h 07m 23s (ML 5.1), 06h 56m 32s (ML 5.2) and 07h 55m 09s (ML 5.2). The earthquakes occurred at the end of summer after a long period of dry weather. Modified Mercalli Intensities of MM IX have been reported in and around Edgecumbe, with possible instances of MM X. Strong motion accelerographs recorded peak ground acceleration of up to 0.33 g within 15 km of the epicentre. The main shock produced a complex series of surface scarps, the longest being about 7 km long striking SW from Edgecumbe. About 1.3 m maximum extension occurred across the scarp with the area to the north-west being downthrown by about a maximum of 1.5 m which continued to subside slowly. Other smaller normal fault traces have also been detected as well as compressional rolls. There was extensive evidence of level ground liquefaction and lateral spreading near rivers. Both these phenomena produced eruption of sands at the ground surface. Some wells were observed to have increased flows or increased pressures whilst others were had decreased flows. General regional subsidence of the alluvial plains in the area up to 2m has been confirmed by levelling completed within three weeks of the earthquake. Structural damage was confined to the alluvial plains in which the town of Edgecumbe is centred. The depth of sediments on the plains is not less than 350 m. There was extensive minor damage to roads. Severe damage to many houses and other single storey structures. A dairy factory complex in Edgecumbe, two paper mills in Kawerau and a paperboard mill in Whakatane all sustained damage, in some cases considerable. At present information on the damage in the paper mills is not available.

scholarly journals The ShakeMaps of the Amatrice, M6, earthquake

2016 ◽  
Vol 59 ◽  
Author(s):  
Licia Faenza ◽  
Valentino Lauciani ◽  
Alberto Michelini
Keyword(s):  
Ground Motion ◽  
Data Exchange ◽  
Main Shock ◽  
Central Italy ◽  
Strong Motion ◽  
Rupture Directivity ◽  
Time Data ◽  
Epicentral Area ◽  
Ground Shaking ◽  
Motion Data

In this paper we describe the performance of the ShakeMap software package and the fully automatic procedure, based on manually revised location and magnitude, during the main event of the Amatrice sequence with special emphasis to the M6 main shock, that struck central Italy on the 24th August 2016 at 1:36:32 UTC. Our results show that the procedure we developed in the last years, with real-time data exchange among those institutions acquiring strong motion data, allows to provide a faithful description of the ground motion experienced throughout a large region in and around the epicentral  area. The prompt availability of the rupture fault model, within three hours after the earthquake occurrence, provided a better descriptions of the level of strong ground motion throughout the affected area.  Progressive addition of  station data and  manual verification of the data insures improvements in the description of the experienced ground motions.  In particular, comparison between the MCS intensity shakemaps and preliminary field macroseismic reports show favourable similarities.  Finally the overall  spatial pattern of the ground motion of the main shock is consistent with reported rupture directivity toward NW and reduced levels of ground shaking toward SW probably linked to the peculiar source effects of the earthquake.

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