of PGV for two events M2 and M1 with M2 > M1 simplifies to:
))((log 12
1
2
10 MMgabPGV
PGV −⋅+=⎟⎟⎠
⎞
⎜⎜⎝
⎛
,
so PGV2 is greater than or equal to PGV1 when b+a·g ≥ 0; that is, g ≤ -b/a (note that a is
negative). In appendix B we show that in this case PGV2 ≥ PGV1 for not only r = 0, but for all r
≥ 0. In order to exclude PGV2 from being smaller than PGV1 – a larger event having smaller
PGV than
/media/vedurstofan/utgafa/skyrslur/2009/VI_2009_012.pdf
earthquake activity north of GrindavíkRecent data show
that uplift has started again, with the center just west of Mt. Thorbjorn.
Uplift was measured from 22. January 2020 until beginning of February and has
started up again during the first half of March. During the first sequence in
January-February, the deformation rate was about 3-4 mm per day with a total of
a 6 cm uplift during the whole
/about-imo/news/more-research-is-needed-to-decipher-the-on-going-activity-at-the-reykjanes-peninsula-as-a-whole
mm, 14 per cent above the 1971 to 2000
mean. In Akureyri the total was 629.2 mm, 21 per cent above the 1971 to 2000
mean. The number of days with precipitation equal to or exceeding 1.0 mm was 153,
5 which is above the 1961 to 1990
average, but the fewest since 2010. In Akureyri these days were 109 in 2016,
six more than in an average year. The absolute maximum 24-hr precipitation
/about-imo/news/the-weather-in-iceland-in-2016
activity in Bardarbunga continues to be strong. Five earthquakes between M4.0-4.6 were detected since the
last meeting of the Advisory Board on Friday. The strongest one was measured M4.6 yesterday at 21:35. About 10
earthquakes between magnitudes M3.0-3.9 were detected over the period. In total around 130 earthquakes were
detected around the caldera since last Friday, or between 20 and 30 per day
/media/jar/Factsheet_Bardarbunga_20150203.pdf
in size.
Seismic activity in Bárðarbunga continues to diminish although it can still be considered strong. The strongest
earthquake since Tuesday was measured M4.3 at 01:26 yesterday. Two other earthquakes stronger then
magnitudes M3.0 were detected over the period. In total around 70 earthquakes were detected around the caldera
since last Tuesday. No earthquake over M5.0 has been detected
/media/jar/Factsheet_Bardarbunga_20150220.pdf
in southern Norway (Fig.1). The glacier has a total area of 5.4 km2 and rangesin altitude from 1390 to 2090 m a.s.l. The glacierhas been mapped repeatedly, the most recent mapis from 1997. Areas calculated from the 1951 and1997 maps reveal an area reduction of about 0.4km2 in this period (Andreassen 1999). Lengthchange observations reveal a net retreat of about 60
m from 1997 to 2006 (data: NVE; e.g
/media/ces/GA_2009_91A_4_Andreassen.pdf
This can now be observed on the web on a graph that updates every five minutes.
At the time of writing (16:00), the level of subsidence exceeds 12 m but this represents only 10% of the expected total. In the coming days, the rate of subsidence will continue to increase. It is possible that radio contact will soon be lost with the GPS station, as subsidence will disrupt the line-of-sight for the radio
/about-imo/news/nr/3203
at one main vent (the fifth opening that opened in the area). The activity last week is still characterized by lava fountains similar to previous weeks. The pulsating behaviour has been rather stable over the last days with normally 7-8 pulses of lava fountains per hour. Fountains can get up to 500 m above sea level and lava spatters and clasts are thrown far away from the crater. Few-cm sized
/earthquakes-and-volcanism/volcanoes/vona-notifications/