Site characterization is a crucial component in assessing seismic hazard, typically involving situ shear-wave velocity ( V S ) depth profiling, and measurement of site amplification including period. Noninvasive methods are ideal for soil sites become challenging terms field logistics interpretation more complex geologic settings rock sites. Multiple noninvasive active- passive-seismic techniqu...

Horizontal ground motion generated by vibration tests of the nine-story Millikan Library Building on the Caltech campus was recorded on 1he surface of the ground in the Pasadena area at distances up to 3 miles from the building. Later it was learned that the vertical component of the motion also was recorded by the seismograph on Mt. Wilson, 6.7 miles from the Library and 4,800 ft higher in ele...

Our understanding of the present-day state and evolution Canadian Alaskan mantle is hindered by a lack absolute P-wavespeed constraints that provide complementary sensitivity to composition in conjunction with existing S-wavespeed models. Consequently, cratonic modification, orogenic history western North America complexities within Proto-Pacific subduction system remain enigmatic. One challeng...

This study considers the use of the joint location techniques for sets of Virginia earthquakes recorded by different station distributions. These input data sets consist of microearthquakes (mb < 3) recorded by local networks (post-1978) and larger, felt events (m~ _-< 4.6) that occurred in the same areas prior to network installation (pre-1978). Very different epicentral geometries (both linea...

The May 18, 1980 Mount St. Helens eruption perturbed the atmosphere and generated atmosphere-to-ground coupled airwaves, which were recorded on at least 35 seismometers operated by the Pacific Northwest Seismograph Network (PNSN). From 102 distinct travel time picks we identify coherent airwaves crossing Washington State primarily to the north and east of the volcano. The travel time curves pro...

Two recent developments in seismometry allow the study of seismic phenomena over a broad period range. Block and Moore [1970] developed a quartz accelerometer with the required stability and sensitivity to record seismic waves as well as earth tides. The instrument, especially useful at periods greater than 80 sec, recorded free oscillations of the earth associated with an earthquake of magnitu...

Abstract This paper presents the depth inversion of Rayleigh wave group velocity to obtain an S-wave model from seismic ambient noise cross-correlation in western Java, Indonesia. study utilizes vertical component data a temporary seismograph network deployed 2016, which was used previous estimate fundamental mode maps. In this study, Neighborhood Algorithm applied invert velocities into 1D she...

The Main Ethiopian Rift (MER) has developed during the 18 Ma-Recent separation of Nubian and Somalian plates. Extension in its central northern sectors is associated with seismic activity active magma intrusion, primarily within rift, where shallow (5 km) seismicity along magmatic centers commonly caused by fluid flow through open fractures hydrothermal systems. However, extent to which similar...

Locating sources of volcano-seismic event is very relevant to monitor and comprehend volcanic processes. Ordinary estimation source seismic events based on phase picking. The most accurate procedure selection the visual inspection records by experts, who employ local characteristics for detection comparison with observed signals from other stations. This activity highly time demanding, which in...