Exploiting the Demographics of “Did You Feel It?” Responses to Estimate the Felt Area of Moderate Earthquakes in California

2017 ◽  
Vol 88 (2A) ◽  
pp. 335-341 ◽  
Author(s):  
John Boatwright ◽  
Eleyne Phillips
Keyword(s):  
Felt Area

REEVALUATION OF THE JANUARY 2, 1912 NORTHERN ILLINOIS EARTHQUAKE: USING GIS AND COMPREHENSIVE MICROFILM ANALYSIS TO ASSESS FELT AREA, INTENSITY, AND EPICENTER

2017 ◽  
Author(s):  
Alexandre Golden ◽  
◽  
Mallorie Gomez ◽  
Kristin T. Huysken ◽  
Kazuya Fujita ◽  
...  
Keyword(s):  
Felt Area

A proposed source model for the great Kau, Hawaii, earthquake of 1868

1988 ◽  
Vol 78 (4) ◽  
pp. 1450-1462
Author(s):  
Max Wyss
Keyword(s):  
The United States ◽  
Source Model ◽  
Recurrence Time ◽  
Sediment Layer ◽  
Ground Shaking ◽  
Mauna Loa ◽  
Rupture Plane ◽  
Felt Area ◽  
Eastern Edge ◽  
Oceanic Sediment

Abstract On 2 April 1868, an earthquake occurred which destroyed all stone buildings in southern Hawaii. It was felt on Kauai Island at 600 km, and ground shaking of intensity VII was reported up to 130 km distance. Based on the magnitude versus felt-area relationship for Hawaii, it is estimated that the magnitude of the earthquake was about 8. The foreshock sequence lasted 5 days, and the aftershocks lasted for years to perhaps a decade. It appears that this earthquake was one of the very few largest events in historic time in the United States, excluding Alaska, but its return period is unknown. It is proposed that the source of this earthquake was slip of the upper crust towards the southeast along a near-horizontal plane at approximately 9 km depth. The rupture plane may have had dimensions of at least 50 km × 80 km. It is proposed that its eastern edge extended from near Mauna Loa's summit to the south along the volcano's southwest rift. In this model, magma intrusions into Mauna Loa and its southwest rift provide the stresses which act perpendicular to the rift and which push the volcano's southwest flank away from the edifice of the island of Hawaii. The oceanic sediment layer upon which this edifice is deposited acts as a layer of weakness containing the fault plane. This model explains the eruptive pattern of Mauna Loa and its southwest rift, as well as the growing separation between the southwest rift zones of the two volcanoes: Kilauea and Mauna Loa. Geodetic monitoring of southern Hawaii, particularly of the area between the two active volcano's southwest rifts, could test this hypothesis and lead to an estimate of the recurrence time.

An empirical study of New England seismicity: 1727-1977

1979 ◽  
Vol 69 (1) ◽  
pp. 159-175
Author(s):  
R. Street ◽  
A. Lacroix
Keyword(s):  
Regression Analysis ◽  
Empirical Study ◽  
New England ◽  
Multiple Regression Analysis ◽  
Multiple Regression ◽  
North American ◽  
Isoseismal Map ◽  
Epicentral Intensity ◽  
Felt Area ◽  
Magnitude Estimates

abstract Isoseismal map measurements and magnitudes of several recent central and northeastern North American earthquakes are related by multiple regression analysis in order that mbLg magnitudes can be estimated for those noninstrumentally-recorded New England events whose total felt area is known to be ≧10,000 km2 and which occurred after 1727. Magnitude estimates of the noninstrumentally-recorded events permit New England seismicity to be studied on a basis other than the heretofore conventional maximum epicentral intensity approach.

A Magnitude-Felt Area Relation in the Evaluation of the Magnitude of Historical Earthquakes

2005 ◽  
Vol 162 (4) ◽  
pp. 729-737 ◽  
Author(s):  
Domenica Termini ◽  
Antonio Teramo ◽  
Giuliana Arrigo
Keyword(s):  
Historical Earthquakes ◽  
Felt Area

Intensities and isoseismal map for the St. Elias earthquake of February 28, 1979

1980 ◽  
Vol 70 (5) ◽  
pp. 1635-1649
Author(s):  
C. W. Stover ◽  
B. G. Reagor ◽  
R. J. Wetmiller
Keyword(s):  
United States ◽  
Maximum Intensity ◽  
Island Region ◽  
Isoseismal Map ◽  
Kodiak Island ◽  
Isoseismal Maps ◽  
Felt Area

abstract The magnitude 7.2 St. Elias earthquake of February 28, 1979 was felt over an area of about 500,000 km2 of Alaska, United States, and Canada. The maximum intensity was VII at Icy Bay Lumber Camp. No major damage resulted as the epicenter was in an unpopulated area of Alaska. Isoseismal maps are also presented for the earthquakes of September 4, 1899, September 10, 1899, 21 hr, October 9, 1900, and July 10, 1958; magnitudes 8.3, 8.6, 8.3, and 7.9, respectively. The felt areas of the 1899 and 1958 earthquakes were not significantly larger than the St. Elias felt area considering the uncertainty of their limit of perceptibility. The October 9, 1900 earthquake appears to be located in the Kodiak Island region and not near Cape Yakatage as previously published.

Historical and recent seismic activity in South Carolina

1972 ◽  
Vol 62 (3) ◽  
pp. 851-864 ◽  
Author(s):  
G. A. Bollinger
Keyword(s):  
South Carolina ◽  
Seismic Activity ◽  
B Value ◽  
Low Noise ◽  
The State ◽  
Seismic Zone ◽  
Recurrence Relationship ◽  
Noise Data ◽  
History Of ◽  
Felt Area

Abstract The seismic history of South Carolina is dominated by the great Charleston earthquake of August 31, 1886. In addition to having several unusual aspects (region essentially free from shocks for preceding 200 years, large felt area, dual epicenter points, “low intensity zone” in West Virginia), that intensity X event seriously perturbed the seismic regime of the area for at least the following 30 years. Of 438 earthquakes reported to have occurred in the state between 1754 and 1971, 402 have been in the Charleston-Summerville area. The remaining 36 shocks form a southeasterly-trending zone of activity that is transverse to the structural grain of the Appalachians. For the 60 shocks assigned an intensity value (1886-1971), a recurrence relationship between the number of earthquakes “N” of maximum intensity “I0” was found to be log N = 0.52-0.31 I0 for IV ≦ I0 ≦ VIII. This corresponds to a “b” value of 0.5 ± 0.1 in log N versus M relationship assuming M = 1 + (2/3)I0. These data suggest a frequency of seismic activity comparable to that reported for the New Madrid seismic zone. Three months of microearthquake monitoring in the Charleston area during the summer of 1971 yielded 505 hr of low-noise data. Sixty-one earthquakes, primarily in swarm occurrence, were recorded. An h value of 1.8 ± 0.5 was determined for these microshock events. This value is similar to that previously observed for a swarm sequence in New Jersey. Four shocks occurred in the state during 1971. Three of these events (May 19, July 31, August 11) were in the central part of the state near Orangeburg, while the third event (July 13) was near Seneca in northwestern South Carolina. All three events had 3.0 < ML < 4.0. Similar episodes of three or four shocks in 1 year happened in 1956 and again in 1965. The Orangeburg area had, according to historical data, been previously free of earthquake epicenters.

App Earthquake Detection and Automatic Mapping of Felt Area

2018 ◽  
Vol 90 (1) ◽  
pp. 305-312 ◽  
Author(s):  
Rémy Bossu ◽  
Robert Steed ◽  
Fréderic Roussel ◽  
Matthieu Landès ◽  
Amaya Fuenzalida ◽  
...  
Keyword(s):  
Earthquake Detection ◽  
Automatic Mapping ◽  
Felt Area

scholarly journals The earthquake that shook central Sjælland, Denmark, November 6, 2001

2008 ◽  
Vol 56 ◽  
pp. 26-37
Author(s):  
T. B. Larsen ◽  
V. Orozova Bekkevold
Keyword(s):  
Quaternary Sediments ◽  
Large Area ◽  
Small Earthquake ◽  
Human Subjectivity ◽  
Richter Scale ◽  
Local Geology ◽  
Felt Area ◽  
Determining Factor

Earthquakes on Sjælland are in general small and seldom felt. The largest earthquakes in the Danish region occur in Skagerrak and Kattegat, and they are felt in NW Jylland (Thy) and in North Sjælland on average several years apart. A small earthquake measuring just 2.8 on the Richter Scale was felt and heard over a surprisingly large area of Sjælland, Denmark on November 6, 2001. The earthquake caused people to abruptly leave their houses near the epicenter, and minor damage to several buildings was observed. The felt area is oriented strongly asymmetrically with respect to the epicenter, but it correlates well with the local geology. Specifically the shaking was felt in a region where the depth to the Top Chalk surface is small, and the thickness of the Quaternary sediments is less than 50 m. In 1869 an earthquake was felt strongly in the exact same area, and contours separating the felt area from the area where nothing was felt coincide almost exactly for the two earthquakes. This supports that geology and not human subjectivity is the determining factor in delineating the felt area for this earthquake.

scholarly journals On the footprints of a major Brazilian Amazon earthquake

2014 ◽  
Vol 86 (3) ◽  
pp. 1115-1129 ◽  
Author(s):  
ALBERTO V. VELOSO
Keyword(s):  
Seismic Waves ◽  
Seismic Event ◽  
Brazilian Amazon ◽  
Maximum Intensity ◽  
Left Bank ◽  
Seismic Parameters ◽  
Recurrence Period ◽  
Historical Accounts ◽  
Felt Area ◽  
Epicenter Location

Combining historical accounts and seismological studies, three hundred years of dormant information emerged as a source of the largest known seismic event that rocked Brazil since the beginning of our colonization. The probable epicenter location of the 1690 tremor lies on the left bank of the Amazon River, about 45 km downstream from the modern day Manaus. A year later, while passing this area, a missionary met witnesses of the tremor and observed remarkable changes in the topography and vegetation along the margin of the river. By 1692 another priest confirmed this event and the occurrence of large waves in the river, which led to the flooding of the Native Indians' terrains. The tremor spread seismic waves throughout the forest and shook indigenous constructions as far as one thousand kilometers away. A calculation of the seismic parameters shows an estimated magnitude of 7, a maximum intensity of IX MM and a felt area of about 2 million km2. Due to the long recurrence period for this type of tremor, the discovery of one of these events is valuable for seismic global intraplate studies. As for Brazil, it unravels the myth that the country was never hit by severe earthquakes.

Pn velocity and other seismic studies from the data of recent southeast Missouri earthquakes

1963 ◽  
Vol 53 (3) ◽  
pp. 661-679 ◽  
Author(s):  
William Stauder ◽  
Gilbert Bollinger
Keyword(s):  
Maximum Intensity ◽  
Inverse Relation ◽  
Time Curve ◽  
Seismic Region ◽  
Arrival Times ◽  
Pn Velocity ◽  
Rayleigh And Love Waves ◽  
Interval Velocities ◽  
Felt Area ◽  
Group Velocities

Abstract Five earthquakes occurred in the southeastern Missouri seismic region during the first seven months of 1962. The largest of these took place on 2 February 1962, and was located near New Madrid. The felt area of this shock covered 35,000 square miles; the maximum intensity was Intensity V in the Modified Mercalli scale. The magnitude is estimated to have been 4 1/2 to 4¾. Pn arrival times from thirty-five stations in the distance range 200 km to 1000 km fit a composite travel time curve for all five earthquakes given by t = 5.56 ± 0.21 sec ⁡ + Δ / ( 8.23 ± 0.02 km / sec ) . This contrasts with interval velocities of 8.3 km/sec to 8.5 km/sec obtained by Herrin and Taggart for this region from the Gnome data. Sn and P and S crustal velocities are also studied. Pulse-like Rayleigh and Love waves were also recorded, each indicating a group velocity maximum at a period of about 6 seconds. The amplitudes of each of these wave types vary strongly, and in an inverse relation, with azimuth about the source. Group velocities correlate with the sedimentary and upper crustal structure along the path.

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