LARGEST QUAKES -
This morning -
5.1 ASCENSION ISLAND REGION
5.4 EASTER ISLAND REGION
5.2 EASTER ISLAND REGION
5.3 KURIL ISLANDS
5.0 MID-INDIAN RIDGE
5.2 CRETE, GREECE
5.1 IZU ISLANDS, JAPAN REGION
5.2 TARAPACA, CHILE
5.9 OFFSHORE BIO-BIO, CHILE
NEW ZEALAND - Christchurch earthquake: Big aftershocks every month for a year. A year from now, Christchurch will still be rattled by a magnitude-four aftershock at least once a month, according to a scientist. Last Tuesday's devastating 6.3 event meant that the quake-weary city, which has experienced 4000 aftershocks since September, has a new sequence of shocks to contend with. Several large shocks were felt yesterday morning, causing further rockfall in Sumner.
A new forecast by a geological hazard modeller shows that despite an initial burst of high-energy shocks, the aftershock sequence has played out as expected. But the Canterbury Plains now has two threads of aftershocks rumbling beneath it. In 12 months, residents will still experience at least one magnitude-four quake a month. Models predict that in the next week Christchurch should expect between one and 10 aftershocks greater than magnitude four and within three weeks the number should drop to one magnitude four every three to four days. The chance of another large aftershock decreases by the day, but seismologists cannot rule out another magnitude-five or six tremor, especially given that the Lyttelton quake was itself believed to be an aftershock.
"A possibility remains for the occurrence of another aftershock greater than magnitude six. However, it is more likely that such an event will not occur."
Scientists are now working to find out how a large quake erupted in an area that was not considered a "weak spot". Aftershocks from the Darfield quake had increased the stress in the earth's crust under Canterbury, especially to the east of the epicentre. But in investigations made after the September tremor, the amount of stress under the Port Hills was not an area of immediate concern. Seismologists identified several high-risk sites based on where aftershocks were occurring - none of these were near Lyttelton. The Lyttelton faultline might have already been near breaking point before September. "It could be that it was a fault that already had a lot of stress built up on it beforehand, so then it wouldn't take much to push it over the edge."
Seismologists will also use computer models to investigate whether the most recent quake has unsettled nearby faultlines. Areas which were considered high-risk after the September quake will be closely monitored. At present, the most recent quake is not believed to have affected the Alpine Fault, which runs along the spine of the South Island and is considered the most likely source of a large quake in New Zealand. Some contention has arisen over whether last Tuesday's quake was in fact an aftershock. While the two quakes were not connected underground, last week's tremor was part of the Darfield quake's seismic aftermath. International academics have suggested that the high energy of the Lyttelton quake and its distance from the Darfield faultline dissociated the two. (maps)
ARKANSAS - A 4.7 temblor hit at 11:00 p.m. Sunday night, and the quaking continued through the night with three substantial aftershocks. . The tremor was rooted four miles from the small town of Greenbriar, 40 miles north of Little Rock. Following the initial shaking, an aftershock of magnitude 3.8 struck 18 minutes later. A 3.6-magnitude quake struck just before 3 a.m., and at 7 a.m. the next morning, they felt a 3.2-magnitude rumbler. Residents in neighboring states of Oklahoma, Missouri, Tennessee and Mississippi reported feeling the earthquake. But even in Greenbriar, the town closest to the quake, police received no reports of injuries or damage. "We probably wouldn't see structural damage until a 5 or 5.5.. What you're going to see now is pictures sway, things fall off the wall.." It was THE STRONGEST QUAKE SINCE 1969 outside of the New Madrid Fault System. More than 700 quakes, albeit small ones, have occurred in the area over the past 6 months.
PHILIPPINES - At least 13 volcanic quakes were recorded around restive BULUSAN Volcano in Sorsogon in the last 24 hours, state volcanologists said Monday morning. The quakes were "lahar-related" — a day after lahar flows affected water supply in parts of Sorsogon. "Continuous heavy rain over Bulusan Volcano yesterday saturated loosely deposited ash and rock fragments and generated small lahar flows to roll down the slopes of the volcano then flowed along river channels." Channel-confined lahar flows were observed along Cogon and Monbon river channels. Other than that, it said no other significant volcanic activity was observed since the last ash explosion on Feb. 21. Earlier, a separate report said lahar flows triggered by heavy rains Sunday affected the supply of drinking water in some parts of Sorsogon. Residents in the affected areas had to walk as far as three kilometers to get drinking water. Meanwhile, Bulusan's status remains at Alert Level 1, meaning the source of activity is hydrothermal and shallow.
In Batangas province, at least six volcanic quakes were recorded in the last 24 hours. Alert Level 1 is still enforced over TAAL Volcano, where the main crater remains strictly off-limits due to sudden occurrence of steam explosions and accumulation of toxic gases. "Moreover, the public is also reminded that the entire Volcano Island is a Permanent Danger Zone (PDZ), and permanent settlement in the island is strictly not recommended."
Meanwhile, in Albay, Phivolcs recorded one volcanic quake in the last 24 hours. Alert Level 1 also remains in effect over MAYON.
TROPICAL STORMS -
No current tropical cyclones.
SEVERE RAIN STORMS, FLOODING, LANDSLIDES -
PAKISTAN - Flood waters lingered in Pakistan in late February, roughly seven months after devastating monsoon rains first struck the country. Although significantly lower than in October 2010, and even December 2010, water levels were noticeably higher in February 2011 than they had been a year earlier. Widespread and heavy monsoon rains in July and August 2010 led to deadly flooding in Pakistan. Months later, large parts of the country remain underwater. Roughly centered around the city of Sukkur is a large irrigation network of levees and canals designed to manage Pakistan’s typically scarce water resources. The 2010 monsoon floods overwhelmed this irrigation network in many places, and created a giant floodwater lake that terminated in Manchhar (or Manchar) Lake. By late February 2011, water levels had receded considerably, but a multitude of water pockets remained, especially northwest of Sukkur. Water levels were also much higher, compared to a year before, near the city of Sanghar. (photos)
AUSTRALIA - Brisbane has recorded ITS WETTEST SUMMER IN 37 YEARS, thanks to ONE OF THE STRONGEST LA NINAS ON RECORD, but things are about to return to normal, a senior meteorologist says.
The Weather Channel says the city recorded close to a metre of rain with a total of 952.6mm - more than double the long term average and the wettest summer since the infamous Cyclone Wanda summer of 1974. 1098.9mm of rain fell in the summer of 1974. "Over to the north the summer rain was even heavier, Maleny just inland from the Sunshine Coast recorded over 1800mm, but still not enough to beat the area's 1974 total of 2038.5mm.
The heavy rain extended across much of the state, with three tropical cyclones dumping massive falls and triggering flash flooding. "Tropical cyclone Tasha crossed the Queensland coast to the south of Cairns early on Christmas morning as a category one system. "Fast forward only a couple of weeks and disastrous flash flooding erupted through Toowoomba on Monday, January 10, with around 100mm of rain falling on the already saturated catchment of the Lockyer River in one hour. Brisbane was also affected a few days later when the Brisbane River burst its banks and rose to levels just short of the 1974 flood. The degree of flooding in the area placed the disaster in the top three of floods, alongside 1893 and 1974." Tropical cyclone Anthony followed shortly after, producing intense wind gusts as it crossed the coast near Bowen. "Then, in early February, tropical cyclone Yasi became ONE OF THE STRONGEST CYCLONES TO CROSS THE QUEENSLAND COAST, producing wind gusts in excess of 250km/h, rain falls of over 200mm in 12 hours and a storm surge up to 2.3 metres above the normal high tide mark." Autumn is bringing the promise of a return to normal. "With the current La Nina now weakening rain should gradually return to average across Queensland during the next few months."
Scientists are warning that Queensland's rainforest areas will take decades to recover from cyclone Yasi. Trees in the region were stripped bare and some were snapped in half by winds in excess of 250 kilometres an hour.
EXTREME HEAT & DROUGHT / WILDFIRES / CLIMATE CHANGE -
AUSTRALIA - WEATHER RECORDS SMASHED as Perth continues to suffer in heat. Perth's summer is officially a record-breaker, and there's no relief in sight. Authorities are bracing for worse to come as the RECORD-BREAKING RUN OF HOT WEATHER enveloping Perth is set to continue well after the official end of summer. The city has already experienced its LONGEST-EVER RUN OF NIGHTS where the minimum temperature did not fall below 20 degrees, and that mark is set to be extended even further in the next week. The number of officially "warm" nights is now 15, breaking the record of 13 set in 1985 and 1990, and the forecast is for more of the same for at least the next seven days. There have been 23 consecutive days of 30-degree plus temperatures in the city, just two short of the record of 25, set in January-February 1988.
The summer has seen 60 such days so far - or about two-thirds of the season - BREAKING THE RECORD of 56 set last year. The city was likely to record its third-warmest February, third-warmest summer, and second-warmest monthly minimum temperature on record. Those readings stood at 31.9 degrees, 34 degrees, and 22.7 degrees respectively this year so far. The warmest February on record was in 1985, when the average maximum temperature was 35.1 degrees, and the average minimum was 22.7 degrees.
The humidity that has stifled Perth for much of the summer was due largely to the cyclones off the Pilbara coast dragging a monsoonal trough down into inland areas. These conditions meant heat built up and was pushed into the city by north-east winds. That weather pattern had also delayed any strong high-pressure systems from coming into the city and removing the humid air. The warm nights have are expected to lead to health problems. An un-acclimatised body builds up stress when the air temperature does not fall below about 22 degrees. The elderly, young children and babies are more prone to heat stress than most people.